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linux/io_uring/io_uring.c
Ranganath V N 915651b7c9 io_uring: Fix code indentation error 
Fix the indentation to ensure consistent code style and improve
readability and to fix the errors:
ERROR: code indent should use tabs where possible
+               return io_net_import_vec(req, kmsg, sr->buf, sr->len, ITER_SOURCE);$

ERROR: code indent should use tabs where possible
+^I^I^I           struct io_big_cqe *big_cqe)$

Tested by running the /scripts/checkpatch.pl

Signed-off-by: Ranganath V N <vnranganath.20@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-10-22 10:56:11 -06:00

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// SPDX-License-Identifier: GPL-2.0
/*
* Shared application/kernel submission and completion ring pairs, for
* supporting fast/efficient IO.
*
* A note on the read/write ordering memory barriers that are matched between
* the application and kernel side.
*
* After the application reads the CQ ring tail, it must use an
* appropriate smp_rmb() to pair with the smp_wmb() the kernel uses
* before writing the tail (using smp_load_acquire to read the tail will
* do). It also needs a smp_mb() before updating CQ head (ordering the
* entry load(s) with the head store), pairing with an implicit barrier
* through a control-dependency in io_get_cqe (smp_store_release to
* store head will do). Failure to do so could lead to reading invalid
* CQ entries.
*
* Likewise, the application must use an appropriate smp_wmb() before
* writing the SQ tail (ordering SQ entry stores with the tail store),
* which pairs with smp_load_acquire in io_get_sqring (smp_store_release
* to store the tail will do). And it needs a barrier ordering the SQ
* head load before writing new SQ entries (smp_load_acquire to read
* head will do).
*
* When using the SQ poll thread (IORING_SETUP_SQPOLL), the application
* needs to check the SQ flags for IORING_SQ_NEED_WAKEUP *after*
* updating the SQ tail; a full memory barrier smp_mb() is needed
* between.
*
* Also see the examples in the liburing library:
*
* git://git.kernel.org/pub/scm/linux/kernel/git/axboe/liburing.git
*
* io_uring also uses READ/WRITE_ONCE() for _any_ store or load that happens
* from data shared between the kernel and application. This is done both
* for ordering purposes, but also to ensure that once a value is loaded from
* data that the application could potentially modify, it remains stable.
*
* Copyright (C) 2018-2019 Jens Axboe
* Copyright (c) 2018-2019 Christoph Hellwig
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/syscalls.h>
#include <net/compat.h>
#include <linux/refcount.h>
#include <linux/uio.h>
#include <linux/bits.h>
#include <linux/sched/signal.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/percpu.h>
#include <linux/slab.h>
#include <linux/bvec.h>
#include <linux/net.h>
#include <net/sock.h>
#include <linux/anon_inodes.h>
#include <linux/sched/mm.h>
#include <linux/uaccess.h>
#include <linux/nospec.h>
#include <linux/fsnotify.h>
#include <linux/fadvise.h>
#include <linux/task_work.h>
#include <linux/io_uring.h>
#include <linux/io_uring/cmd.h>
#include <linux/audit.h>
#include <linux/security.h>
#include <linux/jump_label.h>
#include <asm/shmparam.h>
#define CREATE_TRACE_POINTS
#include <trace/events/io_uring.h>
#include <uapi/linux/io_uring.h>
#include "io-wq.h"
#include "filetable.h"
#include "io_uring.h"
#include "opdef.h"
#include "refs.h"
#include "tctx.h"
#include "register.h"
#include "sqpoll.h"
#include "fdinfo.h"
#include "kbuf.h"
#include "rsrc.h"
#include "cancel.h"
#include "net.h"
#include "notif.h"
#include "waitid.h"
#include "futex.h"
#include "napi.h"
#include "uring_cmd.h"
#include "msg_ring.h"
#include "memmap.h"
#include "zcrx.h"
#include "timeout.h"
#include "poll.h"
#include "rw.h"
#include "alloc_cache.h"
#include "eventfd.h"
#define SQE_COMMON_FLAGS (IOSQE_FIXED_FILE | IOSQE_IO_LINK | \
IOSQE_IO_HARDLINK | IOSQE_ASYNC)
#define IO_REQ_LINK_FLAGS (REQ_F_LINK | REQ_F_HARDLINK)
#define IO_REQ_CLEAN_FLAGS (REQ_F_BUFFER_SELECTED | REQ_F_NEED_CLEANUP | \
REQ_F_INFLIGHT | REQ_F_CREDS | REQ_F_ASYNC_DATA)
#define IO_REQ_CLEAN_SLOW_FLAGS (REQ_F_REFCOUNT | IO_REQ_LINK_FLAGS | \
REQ_F_REISSUE | REQ_F_POLLED | \
IO_REQ_CLEAN_FLAGS)
#define IO_TCTX_REFS_CACHE_NR (1U << 10)
#define IO_COMPL_BATCH 32
#define IO_REQ_ALLOC_BATCH 8
#define IO_LOCAL_TW_DEFAULT_MAX 20
struct io_defer_entry {
struct list_head list;
struct io_kiocb *req;
};
/* requests with any of those set should undergo io_disarm_next() */
#define IO_DISARM_MASK (REQ_F_ARM_LTIMEOUT | REQ_F_LINK_TIMEOUT | REQ_F_FAIL)
/*
* No waiters. It's larger than any valid value of the tw counter
* so that tests against ->cq_wait_nr would fail and skip wake_up().
*/
#define IO_CQ_WAKE_INIT (-1U)
/* Forced wake up if there is a waiter regardless of ->cq_wait_nr */
#define IO_CQ_WAKE_FORCE (IO_CQ_WAKE_INIT >> 1)
static bool io_uring_try_cancel_requests(struct io_ring_ctx *ctx,
struct io_uring_task *tctx,
bool cancel_all,
bool is_sqpoll_thread);
static void io_queue_sqe(struct io_kiocb *req, unsigned int extra_flags);
static void __io_req_caches_free(struct io_ring_ctx *ctx);
static __read_mostly DEFINE_STATIC_KEY_FALSE(io_key_has_sqarray);
struct kmem_cache *req_cachep;
static struct workqueue_struct *iou_wq __ro_after_init;
static int __read_mostly sysctl_io_uring_disabled;
static int __read_mostly sysctl_io_uring_group = -1;
#ifdef CONFIG_SYSCTL
static const struct ctl_table kernel_io_uring_disabled_table[] = {
{
.procname = "io_uring_disabled",
.data = &sysctl_io_uring_disabled,
.maxlen = sizeof(sysctl_io_uring_disabled),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_TWO,
},
{
.procname = "io_uring_group",
.data = &sysctl_io_uring_group,
.maxlen = sizeof(gid_t),
.mode = 0644,
.proc_handler = proc_dointvec,
},
};
#endif
static void io_poison_cached_req(struct io_kiocb *req)
{
req->ctx = IO_URING_PTR_POISON;
req->tctx = IO_URING_PTR_POISON;
req->file = IO_URING_PTR_POISON;
req->creds = IO_URING_PTR_POISON;
req->io_task_work.func = IO_URING_PTR_POISON;
req->apoll = IO_URING_PTR_POISON;
}
static void io_poison_req(struct io_kiocb *req)
{
io_poison_cached_req(req);
req->async_data = IO_URING_PTR_POISON;
req->kbuf = IO_URING_PTR_POISON;
req->comp_list.next = IO_URING_PTR_POISON;
req->file_node = IO_URING_PTR_POISON;
req->link = IO_URING_PTR_POISON;
}
static inline unsigned int __io_cqring_events(struct io_ring_ctx *ctx)
{
return ctx->cached_cq_tail - READ_ONCE(ctx->rings->cq.head);
}
static inline unsigned int __io_cqring_events_user(struct io_ring_ctx *ctx)
{
return READ_ONCE(ctx->rings->cq.tail) - READ_ONCE(ctx->rings->cq.head);
}
static bool io_match_linked(struct io_kiocb *head)
{
struct io_kiocb *req;
io_for_each_link(req, head) {
if (req->flags & REQ_F_INFLIGHT)
return true;
}
return false;
}
/*
* As io_match_task() but protected against racing with linked timeouts.
* User must not hold timeout_lock.
*/
bool io_match_task_safe(struct io_kiocb *head, struct io_uring_task *tctx,
bool cancel_all)
{
bool matched;
if (tctx && head->tctx != tctx)
return false;
if (cancel_all)
return true;
if (head->flags & REQ_F_LINK_TIMEOUT) {
struct io_ring_ctx *ctx = head->ctx;
/* protect against races with linked timeouts */
raw_spin_lock_irq(&ctx->timeout_lock);
matched = io_match_linked(head);
raw_spin_unlock_irq(&ctx->timeout_lock);
} else {
matched = io_match_linked(head);
}
return matched;
}
static inline void req_fail_link_node(struct io_kiocb *req, int res)
{
req_set_fail(req);
io_req_set_res(req, res, 0);
}
static inline void io_req_add_to_cache(struct io_kiocb *req, struct io_ring_ctx *ctx)
{
if (IS_ENABLED(CONFIG_KASAN))
io_poison_cached_req(req);
wq_stack_add_head(&req->comp_list, &ctx->submit_state.free_list);
}
static __cold void io_ring_ctx_ref_free(struct percpu_ref *ref)
{
struct io_ring_ctx *ctx = container_of(ref, struct io_ring_ctx, refs);
complete(&ctx->ref_comp);
}
static __cold void io_fallback_req_func(struct work_struct *work)
{
struct io_ring_ctx *ctx = container_of(work, struct io_ring_ctx,
fallback_work.work);
struct llist_node *node = llist_del_all(&ctx->fallback_llist);
struct io_kiocb *req, *tmp;
struct io_tw_state ts = {};
percpu_ref_get(&ctx->refs);
mutex_lock(&ctx->uring_lock);
llist_for_each_entry_safe(req, tmp, node, io_task_work.node)
req->io_task_work.func(req, ts);
io_submit_flush_completions(ctx);
mutex_unlock(&ctx->uring_lock);
percpu_ref_put(&ctx->refs);
}
static int io_alloc_hash_table(struct io_hash_table *table, unsigned bits)
{
unsigned int hash_buckets;
int i;
do {
hash_buckets = 1U << bits;
table->hbs = kvmalloc_array(hash_buckets, sizeof(table->hbs[0]),
GFP_KERNEL_ACCOUNT);
if (table->hbs)
break;
if (bits == 1)
return -ENOMEM;
bits--;
} while (1);
table->hash_bits = bits;
for (i = 0; i < hash_buckets; i++)
INIT_HLIST_HEAD(&table->hbs[i].list);
return 0;
}
static void io_free_alloc_caches(struct io_ring_ctx *ctx)
{
io_alloc_cache_free(&ctx->apoll_cache, kfree);
io_alloc_cache_free(&ctx->netmsg_cache, io_netmsg_cache_free);
io_alloc_cache_free(&ctx->rw_cache, io_rw_cache_free);
io_alloc_cache_free(&ctx->cmd_cache, io_cmd_cache_free);
io_futex_cache_free(ctx);
io_rsrc_cache_free(ctx);
}
static __cold struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p)
{
struct io_ring_ctx *ctx;
int hash_bits;
bool ret;
ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
if (!ctx)
return NULL;
xa_init(&ctx->io_bl_xa);
/*
* Use 5 bits less than the max cq entries, that should give us around
* 32 entries per hash list if totally full and uniformly spread, but
* don't keep too many buckets to not overconsume memory.
*/
hash_bits = ilog2(p->cq_entries) - 5;
hash_bits = clamp(hash_bits, 1, 8);
if (io_alloc_hash_table(&ctx->cancel_table, hash_bits))
goto err;
if (percpu_ref_init(&ctx->refs, io_ring_ctx_ref_free,
0, GFP_KERNEL))
goto err;
ctx->flags = p->flags;
ctx->hybrid_poll_time = LLONG_MAX;
atomic_set(&ctx->cq_wait_nr, IO_CQ_WAKE_INIT);
init_waitqueue_head(&ctx->sqo_sq_wait);
INIT_LIST_HEAD(&ctx->sqd_list);
INIT_LIST_HEAD(&ctx->cq_overflow_list);
ret = io_alloc_cache_init(&ctx->apoll_cache, IO_POLL_ALLOC_CACHE_MAX,
sizeof(struct async_poll), 0);
ret |= io_alloc_cache_init(&ctx->netmsg_cache, IO_ALLOC_CACHE_MAX,
sizeof(struct io_async_msghdr),
offsetof(struct io_async_msghdr, clear));
ret |= io_alloc_cache_init(&ctx->rw_cache, IO_ALLOC_CACHE_MAX,
sizeof(struct io_async_rw),
offsetof(struct io_async_rw, clear));
ret |= io_alloc_cache_init(&ctx->cmd_cache, IO_ALLOC_CACHE_MAX,
sizeof(struct io_async_cmd),
sizeof(struct io_async_cmd));
ret |= io_futex_cache_init(ctx);
ret |= io_rsrc_cache_init(ctx);
if (ret)
goto free_ref;
init_completion(&ctx->ref_comp);
xa_init_flags(&ctx->personalities, XA_FLAGS_ALLOC1);
mutex_init(&ctx->uring_lock);
init_waitqueue_head(&ctx->cq_wait);
init_waitqueue_head(&ctx->poll_wq);
spin_lock_init(&ctx->completion_lock);
raw_spin_lock_init(&ctx->timeout_lock);
INIT_WQ_LIST(&ctx->iopoll_list);
INIT_LIST_HEAD(&ctx->defer_list);
INIT_LIST_HEAD(&ctx->timeout_list);
INIT_LIST_HEAD(&ctx->ltimeout_list);
init_llist_head(&ctx->work_llist);
INIT_LIST_HEAD(&ctx->tctx_list);
ctx->submit_state.free_list.next = NULL;
INIT_HLIST_HEAD(&ctx->waitid_list);
xa_init_flags(&ctx->zcrx_ctxs, XA_FLAGS_ALLOC);
#ifdef CONFIG_FUTEX
INIT_HLIST_HEAD(&ctx->futex_list);
#endif
INIT_DELAYED_WORK(&ctx->fallback_work, io_fallback_req_func);
INIT_WQ_LIST(&ctx->submit_state.compl_reqs);
INIT_HLIST_HEAD(&ctx->cancelable_uring_cmd);
io_napi_init(ctx);
mutex_init(&ctx->mmap_lock);
return ctx;
free_ref:
percpu_ref_exit(&ctx->refs);
err:
io_free_alloc_caches(ctx);
kvfree(ctx->cancel_table.hbs);
xa_destroy(&ctx->io_bl_xa);
kfree(ctx);
return NULL;
}
static void io_clean_op(struct io_kiocb *req)
{
if (unlikely(req->flags & REQ_F_BUFFER_SELECTED))
io_kbuf_drop_legacy(req);
if (req->flags & REQ_F_NEED_CLEANUP) {
const struct io_cold_def *def = &io_cold_defs[req->opcode];
if (def->cleanup)
def->cleanup(req);
}
if (req->flags & REQ_F_INFLIGHT)
atomic_dec(&req->tctx->inflight_tracked);
if (req->flags & REQ_F_CREDS)
put_cred(req->creds);
if (req->flags & REQ_F_ASYNC_DATA) {
kfree(req->async_data);
req->async_data = NULL;
}
req->flags &= ~IO_REQ_CLEAN_FLAGS;
}
/*
* Mark the request as inflight, so that file cancelation will find it.
* Can be used if the file is an io_uring instance, or if the request itself
* relies on ->mm being alive for the duration of the request.
*/
inline void io_req_track_inflight(struct io_kiocb *req)
{
if (!(req->flags & REQ_F_INFLIGHT)) {
req->flags |= REQ_F_INFLIGHT;
atomic_inc(&req->tctx->inflight_tracked);
}
}
static struct io_kiocb *__io_prep_linked_timeout(struct io_kiocb *req)
{
if (WARN_ON_ONCE(!req->link))
return NULL;
req->flags &= ~REQ_F_ARM_LTIMEOUT;
req->flags |= REQ_F_LINK_TIMEOUT;
/* linked timeouts should have two refs once prep'ed */
io_req_set_refcount(req);
__io_req_set_refcount(req->link, 2);
return req->link;
}
static void io_prep_async_work(struct io_kiocb *req)
{
const struct io_issue_def *def = &io_issue_defs[req->opcode];
struct io_ring_ctx *ctx = req->ctx;
if (!(req->flags & REQ_F_CREDS)) {
req->flags |= REQ_F_CREDS;
req->creds = get_current_cred();
}
req->work.list.next = NULL;
atomic_set(&req->work.flags, 0);
if (req->flags & REQ_F_FORCE_ASYNC)
atomic_or(IO_WQ_WORK_CONCURRENT, &req->work.flags);
if (req->file && !(req->flags & REQ_F_FIXED_FILE))
req->flags |= io_file_get_flags(req->file);
if (req->file && (req->flags & REQ_F_ISREG)) {
bool should_hash = def->hash_reg_file;
/* don't serialize this request if the fs doesn't need it */
if (should_hash && (req->file->f_flags & O_DIRECT) &&
(req->file->f_op->fop_flags & FOP_DIO_PARALLEL_WRITE))
should_hash = false;
if (should_hash || (ctx->flags & IORING_SETUP_IOPOLL))
io_wq_hash_work(&req->work, file_inode(req->file));
} else if (!req->file || !S_ISBLK(file_inode(req->file)->i_mode)) {
if (def->unbound_nonreg_file)
atomic_or(IO_WQ_WORK_UNBOUND, &req->work.flags);
}
}
static void io_prep_async_link(struct io_kiocb *req)
{
struct io_kiocb *cur;
if (req->flags & REQ_F_LINK_TIMEOUT) {
struct io_ring_ctx *ctx = req->ctx;
raw_spin_lock_irq(&ctx->timeout_lock);
io_for_each_link(cur, req)
io_prep_async_work(cur);
raw_spin_unlock_irq(&ctx->timeout_lock);
} else {
io_for_each_link(cur, req)
io_prep_async_work(cur);
}
}
static void io_queue_iowq(struct io_kiocb *req)
{
struct io_uring_task *tctx = req->tctx;
BUG_ON(!tctx);
if ((current->flags & PF_KTHREAD) || !tctx->io_wq) {
io_req_task_queue_fail(req, -ECANCELED);
return;
}
/* init ->work of the whole link before punting */
io_prep_async_link(req);
/*
* Not expected to happen, but if we do have a bug where this _can_
* happen, catch it here and ensure the request is marked as
* canceled. That will make io-wq go through the usual work cancel
* procedure rather than attempt to run this request (or create a new
* worker for it).
*/
if (WARN_ON_ONCE(!same_thread_group(tctx->task, current)))
atomic_or(IO_WQ_WORK_CANCEL, &req->work.flags);
trace_io_uring_queue_async_work(req, io_wq_is_hashed(&req->work));
io_wq_enqueue(tctx->io_wq, &req->work);
}
static void io_req_queue_iowq_tw(struct io_kiocb *req, io_tw_token_t tw)
{
io_queue_iowq(req);
}
void io_req_queue_iowq(struct io_kiocb *req)
{
req->io_task_work.func = io_req_queue_iowq_tw;
io_req_task_work_add(req);
}
static unsigned io_linked_nr(struct io_kiocb *req)
{
struct io_kiocb *tmp;
unsigned nr = 0;
io_for_each_link(tmp, req)
nr++;
return nr;
}
static __cold noinline void io_queue_deferred(struct io_ring_ctx *ctx)
{
bool drain_seen = false, first = true;
lockdep_assert_held(&ctx->uring_lock);
__io_req_caches_free(ctx);
while (!list_empty(&ctx->defer_list)) {
struct io_defer_entry *de = list_first_entry(&ctx->defer_list,
struct io_defer_entry, list);
drain_seen |= de->req->flags & REQ_F_IO_DRAIN;
if ((drain_seen || first) && ctx->nr_req_allocated != ctx->nr_drained)
return;
list_del_init(&de->list);
ctx->nr_drained -= io_linked_nr(de->req);
io_req_task_queue(de->req);
kfree(de);
first = false;
}
}
void __io_commit_cqring_flush(struct io_ring_ctx *ctx)
{
if (ctx->poll_activated)
io_poll_wq_wake(ctx);
if (ctx->off_timeout_used)
io_flush_timeouts(ctx);
if (ctx->has_evfd)
io_eventfd_signal(ctx, true);
}
static inline void __io_cq_lock(struct io_ring_ctx *ctx)
{
if (!ctx->lockless_cq)
spin_lock(&ctx->completion_lock);
}
static inline void io_cq_lock(struct io_ring_ctx *ctx)
__acquires(ctx->completion_lock)
{
spin_lock(&ctx->completion_lock);
}
static inline void __io_cq_unlock_post(struct io_ring_ctx *ctx)
{
io_commit_cqring(ctx);
if (!ctx->task_complete) {
if (!ctx->lockless_cq)
spin_unlock(&ctx->completion_lock);
/* IOPOLL rings only need to wake up if it's also SQPOLL */
if (!ctx->syscall_iopoll)
io_cqring_wake(ctx);
}
io_commit_cqring_flush(ctx);
}
static void io_cq_unlock_post(struct io_ring_ctx *ctx)
__releases(ctx->completion_lock)
{
io_commit_cqring(ctx);
spin_unlock(&ctx->completion_lock);
io_cqring_wake(ctx);
io_commit_cqring_flush(ctx);
}
static void __io_cqring_overflow_flush(struct io_ring_ctx *ctx, bool dying)
{
lockdep_assert_held(&ctx->uring_lock);
/* don't abort if we're dying, entries must get freed */
if (!dying && __io_cqring_events(ctx) == ctx->cq_entries)
return;
io_cq_lock(ctx);
while (!list_empty(&ctx->cq_overflow_list)) {
size_t cqe_size = sizeof(struct io_uring_cqe);
struct io_uring_cqe *cqe;
struct io_overflow_cqe *ocqe;
bool is_cqe32 = false;
ocqe = list_first_entry(&ctx->cq_overflow_list,
struct io_overflow_cqe, list);
if (ocqe->cqe.flags & IORING_CQE_F_32 ||
ctx->flags & IORING_SETUP_CQE32) {
is_cqe32 = true;
cqe_size <<= 1;
}
if (!dying) {
if (!io_get_cqe_overflow(ctx, &cqe, true, is_cqe32))
break;
memcpy(cqe, &ocqe->cqe, cqe_size);
}
list_del(&ocqe->list);
kfree(ocqe);
/*
* For silly syzbot cases that deliberately overflow by huge
* amounts, check if we need to resched and drop and
* reacquire the locks if so. Nothing real would ever hit this.
* Ideally we'd have a non-posting unlock for this, but hard
* to care for a non-real case.
*/
if (need_resched()) {
ctx->cqe_sentinel = ctx->cqe_cached;
io_cq_unlock_post(ctx);
mutex_unlock(&ctx->uring_lock);
cond_resched();
mutex_lock(&ctx->uring_lock);
io_cq_lock(ctx);
}
}
if (list_empty(&ctx->cq_overflow_list)) {
clear_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq);
atomic_andnot(IORING_SQ_CQ_OVERFLOW, &ctx->rings->sq_flags);
}
io_cq_unlock_post(ctx);
}
static void io_cqring_overflow_kill(struct io_ring_ctx *ctx)
{
if (ctx->rings)
__io_cqring_overflow_flush(ctx, true);
}
static void io_cqring_do_overflow_flush(struct io_ring_ctx *ctx)
{
mutex_lock(&ctx->uring_lock);
__io_cqring_overflow_flush(ctx, false);
mutex_unlock(&ctx->uring_lock);
}
/* must to be called somewhat shortly after putting a request */
static inline void io_put_task(struct io_kiocb *req)
{
struct io_uring_task *tctx = req->tctx;
if (likely(tctx->task == current)) {
tctx->cached_refs++;
} else {
percpu_counter_sub(&tctx->inflight, 1);
if (unlikely(atomic_read(&tctx->in_cancel)))
wake_up(&tctx->wait);
put_task_struct(tctx->task);
}
}
void io_task_refs_refill(struct io_uring_task *tctx)
{
unsigned int refill = -tctx->cached_refs + IO_TCTX_REFS_CACHE_NR;
percpu_counter_add(&tctx->inflight, refill);
refcount_add(refill, &current->usage);
tctx->cached_refs += refill;
}
static __cold void io_uring_drop_tctx_refs(struct task_struct *task)
{
struct io_uring_task *tctx = task->io_uring;
unsigned int refs = tctx->cached_refs;
if (refs) {
tctx->cached_refs = 0;
percpu_counter_sub(&tctx->inflight, refs);
put_task_struct_many(task, refs);
}
}
static __cold bool io_cqring_add_overflow(struct io_ring_ctx *ctx,
struct io_overflow_cqe *ocqe)
{
lockdep_assert_held(&ctx->completion_lock);
if (!ocqe) {
struct io_rings *r = ctx->rings;
/*
* If we're in ring overflow flush mode, or in task cancel mode,
* or cannot allocate an overflow entry, then we need to drop it
* on the floor.
*/
WRITE_ONCE(r->cq_overflow, READ_ONCE(r->cq_overflow) + 1);
set_bit(IO_CHECK_CQ_DROPPED_BIT, &ctx->check_cq);
return false;
}
if (list_empty(&ctx->cq_overflow_list)) {
set_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq);
atomic_or(IORING_SQ_CQ_OVERFLOW, &ctx->rings->sq_flags);
}
list_add_tail(&ocqe->list, &ctx->cq_overflow_list);
return true;
}
static struct io_overflow_cqe *io_alloc_ocqe(struct io_ring_ctx *ctx,
struct io_cqe *cqe,
struct io_big_cqe *big_cqe, gfp_t gfp)
{
struct io_overflow_cqe *ocqe;
size_t ocq_size = sizeof(struct io_overflow_cqe);
bool is_cqe32 = false;
if (cqe->flags & IORING_CQE_F_32 || ctx->flags & IORING_SETUP_CQE32) {
is_cqe32 = true;
ocq_size += sizeof(struct io_uring_cqe);
}
ocqe = kzalloc(ocq_size, gfp | __GFP_ACCOUNT);
trace_io_uring_cqe_overflow(ctx, cqe->user_data, cqe->res, cqe->flags, ocqe);
if (ocqe) {
ocqe->cqe.user_data = cqe->user_data;
ocqe->cqe.res = cqe->res;
ocqe->cqe.flags = cqe->flags;
if (is_cqe32 && big_cqe) {
ocqe->cqe.big_cqe[0] = big_cqe->extra1;
ocqe->cqe.big_cqe[1] = big_cqe->extra2;
}
}
if (big_cqe)
big_cqe->extra1 = big_cqe->extra2 = 0;
return ocqe;
}
/*
* Fill an empty dummy CQE, in case alignment is off for posting a 32b CQE
* because the ring is a single 16b entry away from wrapping.
*/
static bool io_fill_nop_cqe(struct io_ring_ctx *ctx, unsigned int off)
{
if (__io_cqring_events(ctx) < ctx->cq_entries) {
struct io_uring_cqe *cqe = &ctx->rings->cqes[off];
cqe->user_data = 0;
cqe->res = 0;
cqe->flags = IORING_CQE_F_SKIP;
ctx->cached_cq_tail++;
return true;
}
return false;
}
/*
* writes to the cq entry need to come after reading head; the
* control dependency is enough as we're using WRITE_ONCE to
* fill the cq entry
*/
bool io_cqe_cache_refill(struct io_ring_ctx *ctx, bool overflow, bool cqe32)
{
struct io_rings *rings = ctx->rings;
unsigned int off = ctx->cached_cq_tail & (ctx->cq_entries - 1);
unsigned int free, queued, len;
/*
* Posting into the CQ when there are pending overflowed CQEs may break
* ordering guarantees, which will affect links, F_MORE users and more.
* Force overflow the completion.
*/
if (!overflow && (ctx->check_cq & BIT(IO_CHECK_CQ_OVERFLOW_BIT)))
return false;
/*
* Post dummy CQE if a 32b CQE is needed and there's only room for a
* 16b CQE before the ring wraps.
*/
if (cqe32 && off + 1 == ctx->cq_entries) {
if (!io_fill_nop_cqe(ctx, off))
return false;
off = 0;
}
/* userspace may cheat modifying the tail, be safe and do min */
queued = min(__io_cqring_events(ctx), ctx->cq_entries);
free = ctx->cq_entries - queued;
/* we need a contiguous range, limit based on the current array offset */
len = min(free, ctx->cq_entries - off);
if (len < (cqe32 + 1))
return false;
if (ctx->flags & IORING_SETUP_CQE32) {
off <<= 1;
len <<= 1;
}
ctx->cqe_cached = &rings->cqes[off];
ctx->cqe_sentinel = ctx->cqe_cached + len;
return true;
}
static bool io_fill_cqe_aux32(struct io_ring_ctx *ctx,
struct io_uring_cqe src_cqe[2])
{
struct io_uring_cqe *cqe;
if (WARN_ON_ONCE(!(ctx->flags & (IORING_SETUP_CQE32|IORING_SETUP_CQE_MIXED))))
return false;
if (unlikely(!io_get_cqe(ctx, &cqe, true)))
return false;
memcpy(cqe, src_cqe, 2 * sizeof(*cqe));
trace_io_uring_complete(ctx, NULL, cqe);
return true;
}
static bool io_fill_cqe_aux(struct io_ring_ctx *ctx, u64 user_data, s32 res,
u32 cflags)
{
bool cqe32 = cflags & IORING_CQE_F_32;
struct io_uring_cqe *cqe;
if (likely(io_get_cqe(ctx, &cqe, cqe32))) {
WRITE_ONCE(cqe->user_data, user_data);
WRITE_ONCE(cqe->res, res);
WRITE_ONCE(cqe->flags, cflags);
if (cqe32) {
WRITE_ONCE(cqe->big_cqe[0], 0);
WRITE_ONCE(cqe->big_cqe[1], 0);
}
trace_io_uring_complete(ctx, NULL, cqe);
return true;
}
return false;
}
static inline struct io_cqe io_init_cqe(u64 user_data, s32 res, u32 cflags)
{
return (struct io_cqe) { .user_data = user_data, .res = res, .flags = cflags };
}
static __cold void io_cqe_overflow(struct io_ring_ctx *ctx, struct io_cqe *cqe,
struct io_big_cqe *big_cqe)
{
struct io_overflow_cqe *ocqe;
ocqe = io_alloc_ocqe(ctx, cqe, big_cqe, GFP_KERNEL);
spin_lock(&ctx->completion_lock);
io_cqring_add_overflow(ctx, ocqe);
spin_unlock(&ctx->completion_lock);
}
static __cold bool io_cqe_overflow_locked(struct io_ring_ctx *ctx,
struct io_cqe *cqe,
struct io_big_cqe *big_cqe)
{
struct io_overflow_cqe *ocqe;
ocqe = io_alloc_ocqe(ctx, cqe, big_cqe, GFP_ATOMIC);
return io_cqring_add_overflow(ctx, ocqe);
}
bool io_post_aux_cqe(struct io_ring_ctx *ctx, u64 user_data, s32 res, u32 cflags)
{
bool filled;
io_cq_lock(ctx);
filled = io_fill_cqe_aux(ctx, user_data, res, cflags);
if (unlikely(!filled)) {
struct io_cqe cqe = io_init_cqe(user_data, res, cflags);
filled = io_cqe_overflow_locked(ctx, &cqe, NULL);
}
io_cq_unlock_post(ctx);
return filled;
}
/*
* Must be called from inline task_work so we now a flush will happen later,
* and obviously with ctx->uring_lock held (tw always has that).
*/
void io_add_aux_cqe(struct io_ring_ctx *ctx, u64 user_data, s32 res, u32 cflags)
{
lockdep_assert_held(&ctx->uring_lock);
lockdep_assert(ctx->lockless_cq);
if (!io_fill_cqe_aux(ctx, user_data, res, cflags)) {
struct io_cqe cqe = io_init_cqe(user_data, res, cflags);
io_cqe_overflow(ctx, &cqe, NULL);
}
ctx->submit_state.cq_flush = true;
}
/*
* A helper for multishot requests posting additional CQEs.
* Should only be used from a task_work including IO_URING_F_MULTISHOT.
*/
bool io_req_post_cqe(struct io_kiocb *req, s32 res, u32 cflags)
{
struct io_ring_ctx *ctx = req->ctx;
bool posted;
/*
* If multishot has already posted deferred completions, ensure that
* those are flushed first before posting this one. If not, CQEs
* could get reordered.
*/
if (!wq_list_empty(&ctx->submit_state.compl_reqs))
__io_submit_flush_completions(ctx);
lockdep_assert(!io_wq_current_is_worker());
lockdep_assert_held(&ctx->uring_lock);
if (!ctx->lockless_cq) {
spin_lock(&ctx->completion_lock);
posted = io_fill_cqe_aux(ctx, req->cqe.user_data, res, cflags);
spin_unlock(&ctx->completion_lock);
} else {
posted = io_fill_cqe_aux(ctx, req->cqe.user_data, res, cflags);
}
ctx->submit_state.cq_flush = true;
return posted;
}
/*
* A helper for multishot requests posting additional CQEs.
* Should only be used from a task_work including IO_URING_F_MULTISHOT.
*/
bool io_req_post_cqe32(struct io_kiocb *req, struct io_uring_cqe cqe[2])
{
struct io_ring_ctx *ctx = req->ctx;
bool posted;
lockdep_assert(!io_wq_current_is_worker());
lockdep_assert_held(&ctx->uring_lock);
cqe[0].user_data = req->cqe.user_data;
if (!ctx->lockless_cq) {
spin_lock(&ctx->completion_lock);
posted = io_fill_cqe_aux32(ctx, cqe);
spin_unlock(&ctx->completion_lock);
} else {
posted = io_fill_cqe_aux32(ctx, cqe);
}
ctx->submit_state.cq_flush = true;
return posted;
}
static void io_req_complete_post(struct io_kiocb *req, unsigned issue_flags)
{
struct io_ring_ctx *ctx = req->ctx;
bool completed = true;
/*
* All execution paths but io-wq use the deferred completions by
* passing IO_URING_F_COMPLETE_DEFER and thus should not end up here.
*/
if (WARN_ON_ONCE(!(issue_flags & IO_URING_F_IOWQ)))
return;
/*
* Handle special CQ sync cases via task_work. DEFER_TASKRUN requires
* the submitter task context, IOPOLL protects with uring_lock.
*/
if (ctx->lockless_cq || (req->flags & REQ_F_REISSUE)) {
defer_complete:
req->io_task_work.func = io_req_task_complete;
io_req_task_work_add(req);
return;
}
io_cq_lock(ctx);
if (!(req->flags & REQ_F_CQE_SKIP))
completed = io_fill_cqe_req(ctx, req);
io_cq_unlock_post(ctx);
if (!completed)
goto defer_complete;
/*
* We don't free the request here because we know it's called from
* io-wq only, which holds a reference, so it cannot be the last put.
*/
req_ref_put(req);
}
void io_req_defer_failed(struct io_kiocb *req, s32 res)
__must_hold(&ctx->uring_lock)
{
const struct io_cold_def *def = &io_cold_defs[req->opcode];
lockdep_assert_held(&req->ctx->uring_lock);
req_set_fail(req);
io_req_set_res(req, res, io_put_kbuf(req, res, NULL));
if (def->fail)
def->fail(req);
io_req_complete_defer(req);
}
/*
* A request might get retired back into the request caches even before opcode
* handlers and io_issue_sqe() are done with it, e.g. inline completion path.
* Because of that, io_alloc_req() should be called only under ->uring_lock
* and with extra caution to not get a request that is still worked on.
*/
__cold bool __io_alloc_req_refill(struct io_ring_ctx *ctx)
__must_hold(&ctx->uring_lock)
{
gfp_t gfp = GFP_KERNEL | __GFP_NOWARN | __GFP_ZERO;
void *reqs[IO_REQ_ALLOC_BATCH];
int ret;
ret = kmem_cache_alloc_bulk(req_cachep, gfp, ARRAY_SIZE(reqs), reqs);
/*
* Bulk alloc is all-or-nothing. If we fail to get a batch,
* retry single alloc to be on the safe side.
*/
if (unlikely(ret <= 0)) {
reqs[0] = kmem_cache_alloc(req_cachep, gfp);
if (!reqs[0])
return false;
ret = 1;
}
percpu_ref_get_many(&ctx->refs, ret);
ctx->nr_req_allocated += ret;
while (ret--) {
struct io_kiocb *req = reqs[ret];
io_req_add_to_cache(req, ctx);
}
return true;
}
__cold void io_free_req(struct io_kiocb *req)
{
/* refs were already put, restore them for io_req_task_complete() */
req->flags &= ~REQ_F_REFCOUNT;
/* we only want to free it, don't post CQEs */
req->flags |= REQ_F_CQE_SKIP;
req->io_task_work.func = io_req_task_complete;
io_req_task_work_add(req);
}
static void __io_req_find_next_prep(struct io_kiocb *req)
{
struct io_ring_ctx *ctx = req->ctx;
spin_lock(&ctx->completion_lock);
io_disarm_next(req);
spin_unlock(&ctx->completion_lock);
}
static inline struct io_kiocb *io_req_find_next(struct io_kiocb *req)
{
struct io_kiocb *nxt;
/*
* If LINK is set, we have dependent requests in this chain. If we
* didn't fail this request, queue the first one up, moving any other
* dependencies to the next request. In case of failure, fail the rest
* of the chain.
*/
if (unlikely(req->flags & IO_DISARM_MASK))
__io_req_find_next_prep(req);
nxt = req->link;
req->link = NULL;
return nxt;
}
static void ctx_flush_and_put(struct io_ring_ctx *ctx, io_tw_token_t tw)
{
if (!ctx)
return;
if (ctx->flags & IORING_SETUP_TASKRUN_FLAG)
atomic_andnot(IORING_SQ_TASKRUN, &ctx->rings->sq_flags);
io_submit_flush_completions(ctx);
mutex_unlock(&ctx->uring_lock);
percpu_ref_put(&ctx->refs);
}
/*
* Run queued task_work, returning the number of entries processed in *count.
* If more entries than max_entries are available, stop processing once this
* is reached and return the rest of the list.
*/
struct llist_node *io_handle_tw_list(struct llist_node *node,
unsigned int *count,
unsigned int max_entries)
{
struct io_ring_ctx *ctx = NULL;
struct io_tw_state ts = { };
do {
struct llist_node *next = node->next;
struct io_kiocb *req = container_of(node, struct io_kiocb,
io_task_work.node);
if (req->ctx != ctx) {
ctx_flush_and_put(ctx, ts);
ctx = req->ctx;
mutex_lock(&ctx->uring_lock);
percpu_ref_get(&ctx->refs);
}
INDIRECT_CALL_2(req->io_task_work.func,
io_poll_task_func, io_req_rw_complete,
req, ts);
node = next;
(*count)++;
if (unlikely(need_resched())) {
ctx_flush_and_put(ctx, ts);
ctx = NULL;
cond_resched();
}
} while (node && *count < max_entries);
ctx_flush_and_put(ctx, ts);
return node;
}
static __cold void __io_fallback_tw(struct llist_node *node, bool sync)
{
struct io_ring_ctx *last_ctx = NULL;
struct io_kiocb *req;
while (node) {
req = container_of(node, struct io_kiocb, io_task_work.node);
node = node->next;
if (last_ctx != req->ctx) {
if (last_ctx) {
if (sync)
flush_delayed_work(&last_ctx->fallback_work);
percpu_ref_put(&last_ctx->refs);
}
last_ctx = req->ctx;
percpu_ref_get(&last_ctx->refs);
}
if (llist_add(&req->io_task_work.node, &last_ctx->fallback_llist))
schedule_delayed_work(&last_ctx->fallback_work, 1);
}
if (last_ctx) {
if (sync)
flush_delayed_work(&last_ctx->fallback_work);
percpu_ref_put(&last_ctx->refs);
}
}
static void io_fallback_tw(struct io_uring_task *tctx, bool sync)
{
struct llist_node *node = llist_del_all(&tctx->task_list);
__io_fallback_tw(node, sync);
}
struct llist_node *tctx_task_work_run(struct io_uring_task *tctx,
unsigned int max_entries,
unsigned int *count)
{
struct llist_node *node;
if (unlikely(current->flags & PF_EXITING)) {
io_fallback_tw(tctx, true);
return NULL;
}
node = llist_del_all(&tctx->task_list);
if (node) {
node = llist_reverse_order(node);
node = io_handle_tw_list(node, count, max_entries);
}
/* relaxed read is enough as only the task itself sets ->in_cancel */
if (unlikely(atomic_read(&tctx->in_cancel)))
io_uring_drop_tctx_refs(current);
trace_io_uring_task_work_run(tctx, *count);
return node;
}
void tctx_task_work(struct callback_head *cb)
{
struct io_uring_task *tctx;
struct llist_node *ret;
unsigned int count = 0;
tctx = container_of(cb, struct io_uring_task, task_work);
ret = tctx_task_work_run(tctx, UINT_MAX, &count);
/* can't happen */
WARN_ON_ONCE(ret);
}
static void io_req_local_work_add(struct io_kiocb *req, unsigned flags)
{
struct io_ring_ctx *ctx = req->ctx;
unsigned nr_wait, nr_tw, nr_tw_prev;
struct llist_node *head;
/* See comment above IO_CQ_WAKE_INIT */
BUILD_BUG_ON(IO_CQ_WAKE_FORCE <= IORING_MAX_CQ_ENTRIES);
/*
* We don't know how many reuqests is there in the link and whether
* they can even be queued lazily, fall back to non-lazy.
*/
if (req->flags & IO_REQ_LINK_FLAGS)
flags &= ~IOU_F_TWQ_LAZY_WAKE;
guard(rcu)();
head = READ_ONCE(ctx->work_llist.first);
do {
nr_tw_prev = 0;
if (head) {
struct io_kiocb *first_req = container_of(head,
struct io_kiocb,
io_task_work.node);
/*
* Might be executed at any moment, rely on
* SLAB_TYPESAFE_BY_RCU to keep it alive.
*/
nr_tw_prev = READ_ONCE(first_req->nr_tw);
}
/*
* Theoretically, it can overflow, but that's fine as one of
* previous adds should've tried to wake the task.
*/
nr_tw = nr_tw_prev + 1;
if (!(flags & IOU_F_TWQ_LAZY_WAKE))
nr_tw = IO_CQ_WAKE_FORCE;
req->nr_tw = nr_tw;
req->io_task_work.node.next = head;
} while (!try_cmpxchg(&ctx->work_llist.first, &head,
&req->io_task_work.node));
/*
* cmpxchg implies a full barrier, which pairs with the barrier
* in set_current_state() on the io_cqring_wait() side. It's used
* to ensure that either we see updated ->cq_wait_nr, or waiters
* going to sleep will observe the work added to the list, which
* is similar to the wait/wawke task state sync.
*/
if (!head) {
if (ctx->flags & IORING_SETUP_TASKRUN_FLAG)
atomic_or(IORING_SQ_TASKRUN, &ctx->rings->sq_flags);
if (ctx->has_evfd)
io_eventfd_signal(ctx, false);
}
nr_wait = atomic_read(&ctx->cq_wait_nr);
/* not enough or no one is waiting */
if (nr_tw < nr_wait)
return;
/* the previous add has already woken it up */
if (nr_tw_prev >= nr_wait)
return;
wake_up_state(ctx->submitter_task, TASK_INTERRUPTIBLE);
}
static void io_req_normal_work_add(struct io_kiocb *req)
{
struct io_uring_task *tctx = req->tctx;
struct io_ring_ctx *ctx = req->ctx;
/* task_work already pending, we're done */
if (!llist_add(&req->io_task_work.node, &tctx->task_list))
return;
if (ctx->flags & IORING_SETUP_TASKRUN_FLAG)
atomic_or(IORING_SQ_TASKRUN, &ctx->rings->sq_flags);
/* SQPOLL doesn't need the task_work added, it'll run it itself */
if (ctx->flags & IORING_SETUP_SQPOLL) {
__set_notify_signal(tctx->task);
return;
}
if (likely(!task_work_add(tctx->task, &tctx->task_work, ctx->notify_method)))
return;
io_fallback_tw(tctx, false);
}
void __io_req_task_work_add(struct io_kiocb *req, unsigned flags)
{
if (req->ctx->flags & IORING_SETUP_DEFER_TASKRUN)
io_req_local_work_add(req, flags);
else
io_req_normal_work_add(req);
}
void io_req_task_work_add_remote(struct io_kiocb *req, unsigned flags)
{
if (WARN_ON_ONCE(!(req->ctx->flags & IORING_SETUP_DEFER_TASKRUN)))
return;
__io_req_task_work_add(req, flags);
}
static void __cold io_move_task_work_from_local(struct io_ring_ctx *ctx)
{
struct llist_node *node = llist_del_all(&ctx->work_llist);
__io_fallback_tw(node, false);
node = llist_del_all(&ctx->retry_llist);
__io_fallback_tw(node, false);
}
static bool io_run_local_work_continue(struct io_ring_ctx *ctx, int events,
int min_events)
{
if (!io_local_work_pending(ctx))
return false;
if (events < min_events)
return true;
if (ctx->flags & IORING_SETUP_TASKRUN_FLAG)
atomic_or(IORING_SQ_TASKRUN, &ctx->rings->sq_flags);
return false;
}
static int __io_run_local_work_loop(struct llist_node **node,
io_tw_token_t tw,
int events)
{
int ret = 0;
while (*node) {
struct llist_node *next = (*node)->next;
struct io_kiocb *req = container_of(*node, struct io_kiocb,
io_task_work.node);
INDIRECT_CALL_2(req->io_task_work.func,
io_poll_task_func, io_req_rw_complete,
req, tw);
*node = next;
if (++ret >= events)
break;
}
return ret;
}
static int __io_run_local_work(struct io_ring_ctx *ctx, io_tw_token_t tw,
int min_events, int max_events)
{
struct llist_node *node;
unsigned int loops = 0;
int ret = 0;
if (WARN_ON_ONCE(ctx->submitter_task != current))
return -EEXIST;
if (ctx->flags & IORING_SETUP_TASKRUN_FLAG)
atomic_andnot(IORING_SQ_TASKRUN, &ctx->rings->sq_flags);
again:
min_events -= ret;
ret = __io_run_local_work_loop(&ctx->retry_llist.first, tw, max_events);
if (ctx->retry_llist.first)
goto retry_done;
/*
* llists are in reverse order, flip it back the right way before
* running the pending items.
*/
node = llist_reverse_order(llist_del_all(&ctx->work_llist));
ret += __io_run_local_work_loop(&node, tw, max_events - ret);
ctx->retry_llist.first = node;
loops++;
if (io_run_local_work_continue(ctx, ret, min_events))
goto again;
retry_done:
io_submit_flush_completions(ctx);
if (io_run_local_work_continue(ctx, ret, min_events))
goto again;
trace_io_uring_local_work_run(ctx, ret, loops);
return ret;
}
static inline int io_run_local_work_locked(struct io_ring_ctx *ctx,
int min_events)
{
struct io_tw_state ts = {};
if (!io_local_work_pending(ctx))
return 0;
return __io_run_local_work(ctx, ts, min_events,
max(IO_LOCAL_TW_DEFAULT_MAX, min_events));
}
static int io_run_local_work(struct io_ring_ctx *ctx, int min_events,
int max_events)
{
struct io_tw_state ts = {};
int ret;
mutex_lock(&ctx->uring_lock);
ret = __io_run_local_work(ctx, ts, min_events, max_events);
mutex_unlock(&ctx->uring_lock);
return ret;
}
static void io_req_task_cancel(struct io_kiocb *req, io_tw_token_t tw)
{
io_tw_lock(req->ctx, tw);
io_req_defer_failed(req, req->cqe.res);
}
void io_req_task_submit(struct io_kiocb *req, io_tw_token_t tw)
{
struct io_ring_ctx *ctx = req->ctx;
io_tw_lock(ctx, tw);
if (unlikely(io_should_terminate_tw(ctx)))
io_req_defer_failed(req, -EFAULT);
else if (req->flags & REQ_F_FORCE_ASYNC)
io_queue_iowq(req);
else
io_queue_sqe(req, 0);
}
void io_req_task_queue_fail(struct io_kiocb *req, int ret)
{
io_req_set_res(req, ret, 0);
req->io_task_work.func = io_req_task_cancel;
io_req_task_work_add(req);
}
void io_req_task_queue(struct io_kiocb *req)
{
req->io_task_work.func = io_req_task_submit;
io_req_task_work_add(req);
}
void io_queue_next(struct io_kiocb *req)
{
struct io_kiocb *nxt = io_req_find_next(req);
if (nxt)
io_req_task_queue(nxt);
}
static inline void io_req_put_rsrc_nodes(struct io_kiocb *req)
{
if (req->file_node) {
io_put_rsrc_node(req->ctx, req->file_node);
req->file_node = NULL;
}
if (req->flags & REQ_F_BUF_NODE)
io_put_rsrc_node(req->ctx, req->buf_node);
}
static void io_free_batch_list(struct io_ring_ctx *ctx,
struct io_wq_work_node *node)
__must_hold(&ctx->uring_lock)
{
do {
struct io_kiocb *req = container_of(node, struct io_kiocb,
comp_list);
if (unlikely(req->flags & IO_REQ_CLEAN_SLOW_FLAGS)) {
if (req->flags & REQ_F_REISSUE) {
node = req->comp_list.next;
req->flags &= ~REQ_F_REISSUE;
io_queue_iowq(req);
continue;
}
if (req->flags & REQ_F_REFCOUNT) {
node = req->comp_list.next;
if (!req_ref_put_and_test(req))
continue;
}
if ((req->flags & REQ_F_POLLED) && req->apoll) {
struct async_poll *apoll = req->apoll;
if (apoll->double_poll)
kfree(apoll->double_poll);
io_cache_free(&ctx->apoll_cache, apoll);
req->flags &= ~REQ_F_POLLED;
}
if (req->flags & IO_REQ_LINK_FLAGS)
io_queue_next(req);
if (unlikely(req->flags & IO_REQ_CLEAN_FLAGS))
io_clean_op(req);
}
io_put_file(req);
io_req_put_rsrc_nodes(req);
io_put_task(req);
node = req->comp_list.next;
io_req_add_to_cache(req, ctx);
} while (node);
}
void __io_submit_flush_completions(struct io_ring_ctx *ctx)
__must_hold(&ctx->uring_lock)
{
struct io_submit_state *state = &ctx->submit_state;
struct io_wq_work_node *node;
__io_cq_lock(ctx);
__wq_list_for_each(node, &state->compl_reqs) {
struct io_kiocb *req = container_of(node, struct io_kiocb,
comp_list);
/*
* Requests marked with REQUEUE should not post a CQE, they
* will go through the io-wq retry machinery and post one
* later.
*/
if (!(req->flags & (REQ_F_CQE_SKIP | REQ_F_REISSUE)) &&
unlikely(!io_fill_cqe_req(ctx, req))) {
if (ctx->lockless_cq)
io_cqe_overflow(ctx, &req->cqe, &req->big_cqe);
else
io_cqe_overflow_locked(ctx, &req->cqe, &req->big_cqe);
}
}
__io_cq_unlock_post(ctx);
if (!wq_list_empty(&state->compl_reqs)) {
io_free_batch_list(ctx, state->compl_reqs.first);
INIT_WQ_LIST(&state->compl_reqs);
}
if (unlikely(ctx->drain_active))
io_queue_deferred(ctx);
ctx->submit_state.cq_flush = false;
}
static unsigned io_cqring_events(struct io_ring_ctx *ctx)
{
/* See comment at the top of this file */
smp_rmb();
return __io_cqring_events(ctx);
}
/*
* We can't just wait for polled events to come to us, we have to actively
* find and complete them.
*/
static __cold void io_iopoll_try_reap_events(struct io_ring_ctx *ctx)
{
if (!(ctx->flags & IORING_SETUP_IOPOLL))
return;
mutex_lock(&ctx->uring_lock);
while (!wq_list_empty(&ctx->iopoll_list)) {
/* let it sleep and repeat later if can't complete a request */
if (io_do_iopoll(ctx, true) == 0)
break;
/*
* Ensure we allow local-to-the-cpu processing to take place,
* in this case we need to ensure that we reap all events.
* Also let task_work, etc. to progress by releasing the mutex
*/
if (need_resched()) {
mutex_unlock(&ctx->uring_lock);
cond_resched();
mutex_lock(&ctx->uring_lock);
}
}
mutex_unlock(&ctx->uring_lock);
if (ctx->flags & IORING_SETUP_DEFER_TASKRUN)
io_move_task_work_from_local(ctx);
}
static int io_iopoll_check(struct io_ring_ctx *ctx, unsigned int min_events)
{
unsigned int nr_events = 0;
unsigned long check_cq;
min_events = min(min_events, ctx->cq_entries);
lockdep_assert_held(&ctx->uring_lock);
if (!io_allowed_run_tw(ctx))
return -EEXIST;
check_cq = READ_ONCE(ctx->check_cq);
if (unlikely(check_cq)) {
if (check_cq & BIT(IO_CHECK_CQ_OVERFLOW_BIT))
__io_cqring_overflow_flush(ctx, false);
/*
* Similarly do not spin if we have not informed the user of any
* dropped CQE.
*/
if (check_cq & BIT(IO_CHECK_CQ_DROPPED_BIT))
return -EBADR;
}
/*
* Don't enter poll loop if we already have events pending.
* If we do, we can potentially be spinning for commands that
* already triggered a CQE (eg in error).
*/
if (io_cqring_events(ctx))
return 0;
do {
int ret = 0;
/*
* If a submit got punted to a workqueue, we can have the
* application entering polling for a command before it gets
* issued. That app will hold the uring_lock for the duration
* of the poll right here, so we need to take a breather every
* now and then to ensure that the issue has a chance to add
* the poll to the issued list. Otherwise we can spin here
* forever, while the workqueue is stuck trying to acquire the
* very same mutex.
*/
if (wq_list_empty(&ctx->iopoll_list) ||
io_task_work_pending(ctx)) {
u32 tail = ctx->cached_cq_tail;
(void) io_run_local_work_locked(ctx, min_events);
if (task_work_pending(current) ||
wq_list_empty(&ctx->iopoll_list)) {
mutex_unlock(&ctx->uring_lock);
io_run_task_work();
mutex_lock(&ctx->uring_lock);
}
/* some requests don't go through iopoll_list */
if (tail != ctx->cached_cq_tail ||
wq_list_empty(&ctx->iopoll_list))
break;
}
ret = io_do_iopoll(ctx, !min_events);
if (unlikely(ret < 0))
return ret;
if (task_sigpending(current))
return -EINTR;
if (need_resched())
break;
nr_events += ret;
} while (nr_events < min_events);
return 0;
}
void io_req_task_complete(struct io_kiocb *req, io_tw_token_t tw)
{
io_req_complete_defer(req);
}
/*
* After the iocb has been issued, it's safe to be found on the poll list.
* Adding the kiocb to the list AFTER submission ensures that we don't
* find it from a io_do_iopoll() thread before the issuer is done
* accessing the kiocb cookie.
*/
static void io_iopoll_req_issued(struct io_kiocb *req, unsigned int issue_flags)
{
struct io_ring_ctx *ctx = req->ctx;
const bool needs_lock = issue_flags & IO_URING_F_UNLOCKED;
/* workqueue context doesn't hold uring_lock, grab it now */
if (unlikely(needs_lock))
mutex_lock(&ctx->uring_lock);
/*
* Track whether we have multiple files in our lists. This will impact
* how we do polling eventually, not spinning if we're on potentially
* different devices.
*/
if (wq_list_empty(&ctx->iopoll_list)) {
ctx->poll_multi_queue = false;
} else if (!ctx->poll_multi_queue) {
struct io_kiocb *list_req;
list_req = container_of(ctx->iopoll_list.first, struct io_kiocb,
comp_list);
if (list_req->file != req->file)
ctx->poll_multi_queue = true;
}
/*
* For fast devices, IO may have already completed. If it has, add
* it to the front so we find it first.
*/
if (READ_ONCE(req->iopoll_completed))
wq_list_add_head(&req->comp_list, &ctx->iopoll_list);
else
wq_list_add_tail(&req->comp_list, &ctx->iopoll_list);
if (unlikely(needs_lock)) {
/*
* If IORING_SETUP_SQPOLL is enabled, sqes are either handle
* in sq thread task context or in io worker task context. If
* current task context is sq thread, we don't need to check
* whether should wake up sq thread.
*/
if ((ctx->flags & IORING_SETUP_SQPOLL) &&
wq_has_sleeper(&ctx->sq_data->wait))
wake_up(&ctx->sq_data->wait);
mutex_unlock(&ctx->uring_lock);
}
}
io_req_flags_t io_file_get_flags(struct file *file)
{
io_req_flags_t res = 0;
BUILD_BUG_ON(REQ_F_ISREG_BIT != REQ_F_SUPPORT_NOWAIT_BIT + 1);
if (S_ISREG(file_inode(file)->i_mode))
res |= REQ_F_ISREG;
if ((file->f_flags & O_NONBLOCK) || (file->f_mode & FMODE_NOWAIT))
res |= REQ_F_SUPPORT_NOWAIT;
return res;
}
static __cold void io_drain_req(struct io_kiocb *req)
__must_hold(&ctx->uring_lock)
{
struct io_ring_ctx *ctx = req->ctx;
bool drain = req->flags & IOSQE_IO_DRAIN;
struct io_defer_entry *de;
de = kmalloc(sizeof(*de), GFP_KERNEL_ACCOUNT);
if (!de) {
io_req_defer_failed(req, -ENOMEM);
return;
}
io_prep_async_link(req);
trace_io_uring_defer(req);
de->req = req;
ctx->nr_drained += io_linked_nr(req);
list_add_tail(&de->list, &ctx->defer_list);
io_queue_deferred(ctx);
if (!drain && list_empty(&ctx->defer_list))
ctx->drain_active = false;
}
static bool io_assign_file(struct io_kiocb *req, const struct io_issue_def *def,
unsigned int issue_flags)
{
if (req->file || !def->needs_file)
return true;
if (req->flags & REQ_F_FIXED_FILE)
req->file = io_file_get_fixed(req, req->cqe.fd, issue_flags);
else
req->file = io_file_get_normal(req, req->cqe.fd);
return !!req->file;
}
#define REQ_ISSUE_SLOW_FLAGS (REQ_F_CREDS | REQ_F_ARM_LTIMEOUT)
static inline int __io_issue_sqe(struct io_kiocb *req,
unsigned int issue_flags,
const struct io_issue_def *def)
{
const struct cred *creds = NULL;
struct io_kiocb *link = NULL;
int ret;
if (unlikely(req->flags & REQ_ISSUE_SLOW_FLAGS)) {
if ((req->flags & REQ_F_CREDS) && req->creds != current_cred())
creds = override_creds(req->creds);
if (req->flags & REQ_F_ARM_LTIMEOUT)
link = __io_prep_linked_timeout(req);
}
if (!def->audit_skip)
audit_uring_entry(req->opcode);
ret = def->issue(req, issue_flags);
if (!def->audit_skip)
audit_uring_exit(!ret, ret);
if (unlikely(creds || link)) {
if (creds)
revert_creds(creds);
if (link)
io_queue_linked_timeout(link);
}
return ret;
}
static int io_issue_sqe(struct io_kiocb *req, unsigned int issue_flags)
{
const struct io_issue_def *def = &io_issue_defs[req->opcode];
int ret;
if (unlikely(!io_assign_file(req, def, issue_flags)))
return -EBADF;
ret = __io_issue_sqe(req, issue_flags, def);
if (ret == IOU_COMPLETE) {
if (issue_flags & IO_URING_F_COMPLETE_DEFER)
io_req_complete_defer(req);
else
io_req_complete_post(req, issue_flags);
return 0;
}
if (ret == IOU_ISSUE_SKIP_COMPLETE) {
ret = 0;
/* If the op doesn't have a file, we're not polling for it */
if ((req->ctx->flags & IORING_SETUP_IOPOLL) && def->iopoll_queue)
io_iopoll_req_issued(req, issue_flags);
}
return ret;
}
int io_poll_issue(struct io_kiocb *req, io_tw_token_t tw)
{
const unsigned int issue_flags = IO_URING_F_NONBLOCK |
IO_URING_F_MULTISHOT |
IO_URING_F_COMPLETE_DEFER;
int ret;
io_tw_lock(req->ctx, tw);
WARN_ON_ONCE(!req->file);
if (WARN_ON_ONCE(req->ctx->flags & IORING_SETUP_IOPOLL))
return -EFAULT;
ret = __io_issue_sqe(req, issue_flags, &io_issue_defs[req->opcode]);
WARN_ON_ONCE(ret == IOU_ISSUE_SKIP_COMPLETE);
return ret;
}
struct io_wq_work *io_wq_free_work(struct io_wq_work *work)
{
struct io_kiocb *req = container_of(work, struct io_kiocb, work);
struct io_kiocb *nxt = NULL;
if (req_ref_put_and_test_atomic(req)) {
if (req->flags & IO_REQ_LINK_FLAGS)
nxt = io_req_find_next(req);
io_free_req(req);
}
return nxt ? &nxt->work : NULL;
}
void io_wq_submit_work(struct io_wq_work *work)
{
struct io_kiocb *req = container_of(work, struct io_kiocb, work);
const struct io_issue_def *def = &io_issue_defs[req->opcode];
unsigned int issue_flags = IO_URING_F_UNLOCKED | IO_URING_F_IOWQ;
bool needs_poll = false;
int ret = 0, err = -ECANCELED;
/* one will be dropped by io_wq_free_work() after returning to io-wq */
if (!(req->flags & REQ_F_REFCOUNT))
__io_req_set_refcount(req, 2);
else
req_ref_get(req);
/* either cancelled or io-wq is dying, so don't touch tctx->iowq */
if (atomic_read(&work->flags) & IO_WQ_WORK_CANCEL) {
fail:
io_req_task_queue_fail(req, err);
return;
}
if (!io_assign_file(req, def, issue_flags)) {
err = -EBADF;
atomic_or(IO_WQ_WORK_CANCEL, &work->flags);
goto fail;
}
/*
* If DEFER_TASKRUN is set, it's only allowed to post CQEs from the
* submitter task context. Final request completions are handed to the
* right context, however this is not the case of auxiliary CQEs,
* which is the main mean of operation for multishot requests.
* Don't allow any multishot execution from io-wq. It's more restrictive
* than necessary and also cleaner.
*/
if (req->flags & (REQ_F_MULTISHOT|REQ_F_APOLL_MULTISHOT)) {
err = -EBADFD;
if (!io_file_can_poll(req))
goto fail;
if (req->file->f_flags & O_NONBLOCK ||
req->file->f_mode & FMODE_NOWAIT) {
err = -ECANCELED;
if (io_arm_poll_handler(req, issue_flags) != IO_APOLL_OK)
goto fail;
return;
} else {
req->flags &= ~(REQ_F_APOLL_MULTISHOT|REQ_F_MULTISHOT);
}
}
if (req->flags & REQ_F_FORCE_ASYNC) {
bool opcode_poll = def->pollin || def->pollout;
if (opcode_poll && io_file_can_poll(req)) {
needs_poll = true;
issue_flags |= IO_URING_F_NONBLOCK;
}
}
do {
ret = io_issue_sqe(req, issue_flags);
if (ret != -EAGAIN)
break;
/*
* If REQ_F_NOWAIT is set, then don't wait or retry with
* poll. -EAGAIN is final for that case.
*/
if (req->flags & REQ_F_NOWAIT)
break;
/*
* We can get EAGAIN for iopolled IO even though we're
* forcing a sync submission from here, since we can't
* wait for request slots on the block side.
*/
if (!needs_poll) {
if (!(req->ctx->flags & IORING_SETUP_IOPOLL))
break;
if (io_wq_worker_stopped())
break;
cond_resched();
continue;
}
if (io_arm_poll_handler(req, issue_flags) == IO_APOLL_OK)
return;
/* aborted or ready, in either case retry blocking */
needs_poll = false;
issue_flags &= ~IO_URING_F_NONBLOCK;
} while (1);
/* avoid locking problems by failing it from a clean context */
if (ret)
io_req_task_queue_fail(req, ret);
}
inline struct file *io_file_get_fixed(struct io_kiocb *req, int fd,
unsigned int issue_flags)
{
struct io_ring_ctx *ctx = req->ctx;
struct io_rsrc_node *node;
struct file *file = NULL;
io_ring_submit_lock(ctx, issue_flags);
node = io_rsrc_node_lookup(&ctx->file_table.data, fd);
if (node) {
node->refs++;
req->file_node = node;
req->flags |= io_slot_flags(node);
file = io_slot_file(node);
}
io_ring_submit_unlock(ctx, issue_flags);
return file;
}
struct file *io_file_get_normal(struct io_kiocb *req, int fd)
{
struct file *file = fget(fd);
trace_io_uring_file_get(req, fd);
/* we don't allow fixed io_uring files */
if (file && io_is_uring_fops(file))
io_req_track_inflight(req);
return file;
}
static int io_req_sqe_copy(struct io_kiocb *req, unsigned int issue_flags)
{
const struct io_cold_def *def = &io_cold_defs[req->opcode];
if (req->flags & REQ_F_SQE_COPIED)
return 0;
req->flags |= REQ_F_SQE_COPIED;
if (!def->sqe_copy)
return 0;
if (WARN_ON_ONCE(!(issue_flags & IO_URING_F_INLINE)))
return -EFAULT;
def->sqe_copy(req);
return 0;
}
static void io_queue_async(struct io_kiocb *req, unsigned int issue_flags, int ret)
__must_hold(&req->ctx->uring_lock)
{
if (ret != -EAGAIN || (req->flags & REQ_F_NOWAIT)) {
fail:
io_req_defer_failed(req, ret);
return;
}
ret = io_req_sqe_copy(req, issue_flags);
if (unlikely(ret))
goto fail;
switch (io_arm_poll_handler(req, 0)) {
case IO_APOLL_READY:
io_req_task_queue(req);
break;
case IO_APOLL_ABORTED:
io_queue_iowq(req);
break;
case IO_APOLL_OK:
break;
}
}
static inline void io_queue_sqe(struct io_kiocb *req, unsigned int extra_flags)
__must_hold(&req->ctx->uring_lock)
{
unsigned int issue_flags = IO_URING_F_NONBLOCK |
IO_URING_F_COMPLETE_DEFER | extra_flags;
int ret;
ret = io_issue_sqe(req, issue_flags);
/*
* We async punt it if the file wasn't marked NOWAIT, or if the file
* doesn't support non-blocking read/write attempts
*/
if (unlikely(ret))
io_queue_async(req, issue_flags, ret);
}
static void io_queue_sqe_fallback(struct io_kiocb *req)
__must_hold(&req->ctx->uring_lock)
{
if (unlikely(req->flags & REQ_F_FAIL)) {
/*
* We don't submit, fail them all, for that replace hardlinks
* with normal links. Extra REQ_F_LINK is tolerated.
*/
req->flags &= ~REQ_F_HARDLINK;
req->flags |= REQ_F_LINK;
io_req_defer_failed(req, req->cqe.res);
} else {
/* can't fail with IO_URING_F_INLINE */
io_req_sqe_copy(req, IO_URING_F_INLINE);
if (unlikely(req->ctx->drain_active))
io_drain_req(req);
else
io_queue_iowq(req);
}
}
/*
* Check SQE restrictions (opcode and flags).
*
* Returns 'true' if SQE is allowed, 'false' otherwise.
*/
static inline bool io_check_restriction(struct io_ring_ctx *ctx,
struct io_kiocb *req,
unsigned int sqe_flags)
{
if (!test_bit(req->opcode, ctx->restrictions.sqe_op))
return false;
if ((sqe_flags & ctx->restrictions.sqe_flags_required) !=
ctx->restrictions.sqe_flags_required)
return false;
if (sqe_flags & ~(ctx->restrictions.sqe_flags_allowed |
ctx->restrictions.sqe_flags_required))
return false;
return true;
}
static void io_init_drain(struct io_ring_ctx *ctx)
{
struct io_kiocb *head = ctx->submit_state.link.head;
ctx->drain_active = true;
if (head) {
/*
* If we need to drain a request in the middle of a link, drain
* the head request and the next request/link after the current
* link. Considering sequential execution of links,
* REQ_F_IO_DRAIN will be maintained for every request of our
* link.
*/
head->flags |= REQ_F_IO_DRAIN | REQ_F_FORCE_ASYNC;
ctx->drain_next = true;
}
}
static __cold int io_init_fail_req(struct io_kiocb *req, int err)
{
/* ensure per-opcode data is cleared if we fail before prep */
memset(&req->cmd.data, 0, sizeof(req->cmd.data));
return err;
}
static int io_init_req(struct io_ring_ctx *ctx, struct io_kiocb *req,
const struct io_uring_sqe *sqe)
__must_hold(&ctx->uring_lock)
{
const struct io_issue_def *def;
unsigned int sqe_flags;
int personality;
u8 opcode;
req->ctx = ctx;
req->opcode = opcode = READ_ONCE(sqe->opcode);
/* same numerical values with corresponding REQ_F_*, safe to copy */
sqe_flags = READ_ONCE(sqe->flags);
req->flags = (__force io_req_flags_t) sqe_flags;
req->cqe.user_data = READ_ONCE(sqe->user_data);
req->file = NULL;
req->tctx = current->io_uring;
req->cancel_seq_set = false;
req->async_data = NULL;
if (unlikely(opcode >= IORING_OP_LAST)) {
req->opcode = 0;
return io_init_fail_req(req, -EINVAL);
}
opcode = array_index_nospec(opcode, IORING_OP_LAST);
def = &io_issue_defs[opcode];
if (unlikely(sqe_flags & ~SQE_COMMON_FLAGS)) {
/* enforce forwards compatibility on users */
if (sqe_flags & ~SQE_VALID_FLAGS)
return io_init_fail_req(req, -EINVAL);
if (sqe_flags & IOSQE_BUFFER_SELECT) {
if (!def->buffer_select)
return io_init_fail_req(req, -EOPNOTSUPP);
req->buf_index = READ_ONCE(sqe->buf_group);
}
if (sqe_flags & IOSQE_CQE_SKIP_SUCCESS)
ctx->drain_disabled = true;
if (sqe_flags & IOSQE_IO_DRAIN) {
if (ctx->drain_disabled)
return io_init_fail_req(req, -EOPNOTSUPP);
io_init_drain(ctx);
}
}
if (unlikely(ctx->restricted || ctx->drain_active || ctx->drain_next)) {
if (ctx->restricted && !io_check_restriction(ctx, req, sqe_flags))
return io_init_fail_req(req, -EACCES);
/* knock it to the slow queue path, will be drained there */
if (ctx->drain_active)
req->flags |= REQ_F_FORCE_ASYNC;
/* if there is no link, we're at "next" request and need to drain */
if (unlikely(ctx->drain_next) && !ctx->submit_state.link.head) {
ctx->drain_next = false;
ctx->drain_active = true;
req->flags |= REQ_F_IO_DRAIN | REQ_F_FORCE_ASYNC;
}
}
if (!def->ioprio && sqe->ioprio)
return io_init_fail_req(req, -EINVAL);
if (!def->iopoll && (ctx->flags & IORING_SETUP_IOPOLL))
return io_init_fail_req(req, -EINVAL);
if (def->needs_file) {
struct io_submit_state *state = &ctx->submit_state;
req->cqe.fd = READ_ONCE(sqe->fd);
/*
* Plug now if we have more than 2 IO left after this, and the
* target is potentially a read/write to block based storage.
*/
if (state->need_plug && def->plug) {
state->plug_started = true;
state->need_plug = false;
blk_start_plug_nr_ios(&state->plug, state->submit_nr);
}
}
personality = READ_ONCE(sqe->personality);
if (personality) {
int ret;
req->creds = xa_load(&ctx->personalities, personality);
if (!req->creds)
return io_init_fail_req(req, -EINVAL);
get_cred(req->creds);
ret = security_uring_override_creds(req->creds);
if (ret) {
put_cred(req->creds);
return io_init_fail_req(req, ret);
}
req->flags |= REQ_F_CREDS;
}
return def->prep(req, sqe);
}
static __cold int io_submit_fail_init(const struct io_uring_sqe *sqe,
struct io_kiocb *req, int ret)
{
struct io_ring_ctx *ctx = req->ctx;
struct io_submit_link *link = &ctx->submit_state.link;
struct io_kiocb *head = link->head;
trace_io_uring_req_failed(sqe, req, ret);
/*
* Avoid breaking links in the middle as it renders links with SQPOLL
* unusable. Instead of failing eagerly, continue assembling the link if
* applicable and mark the head with REQ_F_FAIL. The link flushing code
* should find the flag and handle the rest.
*/
req_fail_link_node(req, ret);
if (head && !(head->flags & REQ_F_FAIL))
req_fail_link_node(head, -ECANCELED);
if (!(req->flags & IO_REQ_LINK_FLAGS)) {
if (head) {
link->last->link = req;
link->head = NULL;
req = head;
}
io_queue_sqe_fallback(req);
return ret;
}
if (head)
link->last->link = req;
else
link->head = req;
link->last = req;
return 0;
}
static inline int io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req,
const struct io_uring_sqe *sqe)
__must_hold(&ctx->uring_lock)
{
struct io_submit_link *link = &ctx->submit_state.link;
int ret;
ret = io_init_req(ctx, req, sqe);
if (unlikely(ret))
return io_submit_fail_init(sqe, req, ret);
trace_io_uring_submit_req(req);
/*
* If we already have a head request, queue this one for async
* submittal once the head completes. If we don't have a head but
* IOSQE_IO_LINK is set in the sqe, start a new head. This one will be
* submitted sync once the chain is complete. If none of those
* conditions are true (normal request), then just queue it.
*/
if (unlikely(link->head)) {
trace_io_uring_link(req, link->last);
io_req_sqe_copy(req, IO_URING_F_INLINE);
link->last->link = req;
link->last = req;
if (req->flags & IO_REQ_LINK_FLAGS)
return 0;
/* last request of the link, flush it */
req = link->head;
link->head = NULL;
if (req->flags & (REQ_F_FORCE_ASYNC | REQ_F_FAIL))
goto fallback;
} else if (unlikely(req->flags & (IO_REQ_LINK_FLAGS |
REQ_F_FORCE_ASYNC | REQ_F_FAIL))) {
if (req->flags & IO_REQ_LINK_FLAGS) {
link->head = req;
link->last = req;
} else {
fallback:
io_queue_sqe_fallback(req);
}
return 0;
}
io_queue_sqe(req, IO_URING_F_INLINE);
return 0;
}
/*
* Batched submission is done, ensure local IO is flushed out.
*/
static void io_submit_state_end(struct io_ring_ctx *ctx)
{
struct io_submit_state *state = &ctx->submit_state;
if (unlikely(state->link.head))
io_queue_sqe_fallback(state->link.head);
/* flush only after queuing links as they can generate completions */
io_submit_flush_completions(ctx);
if (state->plug_started)
blk_finish_plug(&state->plug);
}
/*
* Start submission side cache.
*/
static void io_submit_state_start(struct io_submit_state *state,
unsigned int max_ios)
{
state->plug_started = false;
state->need_plug = max_ios > 2;
state->submit_nr = max_ios;
/* set only head, no need to init link_last in advance */
state->link.head = NULL;
}
static void io_commit_sqring(struct io_ring_ctx *ctx)
{
struct io_rings *rings = ctx->rings;
/*
* Ensure any loads from the SQEs are done at this point,
* since once we write the new head, the application could
* write new data to them.
*/
smp_store_release(&rings->sq.head, ctx->cached_sq_head);
}
/*
* Fetch an sqe, if one is available. Note this returns a pointer to memory
* that is mapped by userspace. This means that care needs to be taken to
* ensure that reads are stable, as we cannot rely on userspace always
* being a good citizen. If members of the sqe are validated and then later
* used, it's important that those reads are done through READ_ONCE() to
* prevent a re-load down the line.
*/
static bool io_get_sqe(struct io_ring_ctx *ctx, const struct io_uring_sqe **sqe)
{
unsigned mask = ctx->sq_entries - 1;
unsigned head = ctx->cached_sq_head++ & mask;
if (static_branch_unlikely(&io_key_has_sqarray) &&
(!(ctx->flags & IORING_SETUP_NO_SQARRAY))) {
head = READ_ONCE(ctx->sq_array[head]);
if (unlikely(head >= ctx->sq_entries)) {
WRITE_ONCE(ctx->rings->sq_dropped,
READ_ONCE(ctx->rings->sq_dropped) + 1);
return false;
}
head = array_index_nospec(head, ctx->sq_entries);
}
/*
* The cached sq head (or cq tail) serves two purposes:
*
* 1) allows us to batch the cost of updating the user visible
* head updates.
* 2) allows the kernel side to track the head on its own, even
* though the application is the one updating it.
*/
/* double index for 128-byte SQEs, twice as long */
if (ctx->flags & IORING_SETUP_SQE128)
head <<= 1;
*sqe = &ctx->sq_sqes[head];
return true;
}
int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr)
__must_hold(&ctx->uring_lock)
{
unsigned int entries = io_sqring_entries(ctx);
unsigned int left;
int ret;
if (unlikely(!entries))
return 0;
/* make sure SQ entry isn't read before tail */
ret = left = min(nr, entries);
io_get_task_refs(left);
io_submit_state_start(&ctx->submit_state, left);
do {
const struct io_uring_sqe *sqe;
struct io_kiocb *req;
if (unlikely(!io_alloc_req(ctx, &req)))
break;
if (unlikely(!io_get_sqe(ctx, &sqe))) {
io_req_add_to_cache(req, ctx);
break;
}
/*
* Continue submitting even for sqe failure if the
* ring was setup with IORING_SETUP_SUBMIT_ALL
*/
if (unlikely(io_submit_sqe(ctx, req, sqe)) &&
!(ctx->flags & IORING_SETUP_SUBMIT_ALL)) {
left--;
break;
}
} while (--left);
if (unlikely(left)) {
ret -= left;
/* try again if it submitted nothing and can't allocate a req */
if (!ret && io_req_cache_empty(ctx))
ret = -EAGAIN;
current->io_uring->cached_refs += left;
}
io_submit_state_end(ctx);
/* Commit SQ ring head once we've consumed and submitted all SQEs */
io_commit_sqring(ctx);
return ret;
}
static int io_wake_function(struct wait_queue_entry *curr, unsigned int mode,
int wake_flags, void *key)
{
struct io_wait_queue *iowq = container_of(curr, struct io_wait_queue, wq);
/*
* Cannot safely flush overflowed CQEs from here, ensure we wake up
* the task, and the next invocation will do it.
*/
if (io_should_wake(iowq) || io_has_work(iowq->ctx))
return autoremove_wake_function(curr, mode, wake_flags, key);
return -1;
}
int io_run_task_work_sig(struct io_ring_ctx *ctx)
{
if (io_local_work_pending(ctx)) {
__set_current_state(TASK_RUNNING);
if (io_run_local_work(ctx, INT_MAX, IO_LOCAL_TW_DEFAULT_MAX) > 0)
return 0;
}
if (io_run_task_work() > 0)
return 0;
if (task_sigpending(current))
return -EINTR;
return 0;
}
static bool current_pending_io(void)
{
struct io_uring_task *tctx = current->io_uring;
if (!tctx)
return false;
return percpu_counter_read_positive(&tctx->inflight);
}
static enum hrtimer_restart io_cqring_timer_wakeup(struct hrtimer *timer)
{
struct io_wait_queue *iowq = container_of(timer, struct io_wait_queue, t);
WRITE_ONCE(iowq->hit_timeout, 1);
iowq->min_timeout = 0;
wake_up_process(iowq->wq.private);
return HRTIMER_NORESTART;
}
/*
* Doing min_timeout portion. If we saw any timeouts, events, or have work,
* wake up. If not, and we have a normal timeout, switch to that and keep
* sleeping.
*/
static enum hrtimer_restart io_cqring_min_timer_wakeup(struct hrtimer *timer)
{
struct io_wait_queue *iowq = container_of(timer, struct io_wait_queue, t);
struct io_ring_ctx *ctx = iowq->ctx;
/* no general timeout, or shorter (or equal), we are done */
if (iowq->timeout == KTIME_MAX ||
ktime_compare(iowq->min_timeout, iowq->timeout) >= 0)
goto out_wake;
/* work we may need to run, wake function will see if we need to wake */
if (io_has_work(ctx))
goto out_wake;
/* got events since we started waiting, min timeout is done */
if (iowq->cq_min_tail != READ_ONCE(ctx->rings->cq.tail))
goto out_wake;
/* if we have any events and min timeout expired, we're done */
if (io_cqring_events(ctx))
goto out_wake;
/*
* If using deferred task_work running and application is waiting on
* more than one request, ensure we reset it now where we are switching
* to normal sleeps. Any request completion post min_wait should wake
* the task and return.
*/
if (ctx->flags & IORING_SETUP_DEFER_TASKRUN) {
atomic_set(&ctx->cq_wait_nr, 1);
smp_mb();
if (!llist_empty(&ctx->work_llist))
goto out_wake;
}
hrtimer_update_function(&iowq->t, io_cqring_timer_wakeup);
hrtimer_set_expires(timer, iowq->timeout);
return HRTIMER_RESTART;
out_wake:
return io_cqring_timer_wakeup(timer);
}
static int io_cqring_schedule_timeout(struct io_wait_queue *iowq,
clockid_t clock_id, ktime_t start_time)
{
ktime_t timeout;
if (iowq->min_timeout) {
timeout = ktime_add_ns(iowq->min_timeout, start_time);
hrtimer_setup_on_stack(&iowq->t, io_cqring_min_timer_wakeup, clock_id,
HRTIMER_MODE_ABS);
} else {
timeout = iowq->timeout;
hrtimer_setup_on_stack(&iowq->t, io_cqring_timer_wakeup, clock_id,
HRTIMER_MODE_ABS);
}
hrtimer_set_expires_range_ns(&iowq->t, timeout, 0);
hrtimer_start_expires(&iowq->t, HRTIMER_MODE_ABS);
if (!READ_ONCE(iowq->hit_timeout))
schedule();
hrtimer_cancel(&iowq->t);
destroy_hrtimer_on_stack(&iowq->t);
__set_current_state(TASK_RUNNING);
return READ_ONCE(iowq->hit_timeout) ? -ETIME : 0;
}
struct ext_arg {
size_t argsz;
struct timespec64 ts;
const sigset_t __user *sig;
ktime_t min_time;
bool ts_set;
bool iowait;
};
static int __io_cqring_wait_schedule(struct io_ring_ctx *ctx,
struct io_wait_queue *iowq,
struct ext_arg *ext_arg,
ktime_t start_time)
{
int ret = 0;
/*
* Mark us as being in io_wait if we have pending requests, so cpufreq
* can take into account that the task is waiting for IO - turns out
* to be important for low QD IO.
*/
if (ext_arg->iowait && current_pending_io())
current->in_iowait = 1;
if (iowq->timeout != KTIME_MAX || iowq->min_timeout)
ret = io_cqring_schedule_timeout(iowq, ctx->clockid, start_time);
else
schedule();
current->in_iowait = 0;
return ret;
}
/* If this returns > 0, the caller should retry */
static inline int io_cqring_wait_schedule(struct io_ring_ctx *ctx,
struct io_wait_queue *iowq,
struct ext_arg *ext_arg,
ktime_t start_time)
{
if (unlikely(READ_ONCE(ctx->check_cq)))
return 1;
if (unlikely(io_local_work_pending(ctx)))
return 1;
if (unlikely(task_work_pending(current)))
return 1;
if (unlikely(task_sigpending(current)))
return -EINTR;
if (unlikely(io_should_wake(iowq)))
return 0;
return __io_cqring_wait_schedule(ctx, iowq, ext_arg, start_time);
}
/*
* Wait until events become available, if we don't already have some. The
* application must reap them itself, as they reside on the shared cq ring.
*/
static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events, u32 flags,
struct ext_arg *ext_arg)
{
struct io_wait_queue iowq;
struct io_rings *rings = ctx->rings;
ktime_t start_time;
int ret;
min_events = min_t(int, min_events, ctx->cq_entries);
if (!io_allowed_run_tw(ctx))
return -EEXIST;
if (io_local_work_pending(ctx))
io_run_local_work(ctx, min_events,
max(IO_LOCAL_TW_DEFAULT_MAX, min_events));
io_run_task_work();
if (unlikely(test_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq)))
io_cqring_do_overflow_flush(ctx);
if (__io_cqring_events_user(ctx) >= min_events)
return 0;
init_waitqueue_func_entry(&iowq.wq, io_wake_function);
iowq.wq.private = current;
INIT_LIST_HEAD(&iowq.wq.entry);
iowq.ctx = ctx;
iowq.cq_tail = READ_ONCE(ctx->rings->cq.head) + min_events;
iowq.cq_min_tail = READ_ONCE(ctx->rings->cq.tail);
iowq.nr_timeouts = atomic_read(&ctx->cq_timeouts);
iowq.hit_timeout = 0;
iowq.min_timeout = ext_arg->min_time;
iowq.timeout = KTIME_MAX;
start_time = io_get_time(ctx);
if (ext_arg->ts_set) {
iowq.timeout = timespec64_to_ktime(ext_arg->ts);
if (!(flags & IORING_ENTER_ABS_TIMER))
iowq.timeout = ktime_add(iowq.timeout, start_time);
}
if (ext_arg->sig) {
#ifdef CONFIG_COMPAT
if (in_compat_syscall())
ret = set_compat_user_sigmask((const compat_sigset_t __user *)ext_arg->sig,
ext_arg->argsz);
else
#endif
ret = set_user_sigmask(ext_arg->sig, ext_arg->argsz);
if (ret)
return ret;
}
io_napi_busy_loop(ctx, &iowq);
trace_io_uring_cqring_wait(ctx, min_events);
do {
unsigned long check_cq;
int nr_wait;
/* if min timeout has been hit, don't reset wait count */
if (!iowq.hit_timeout)
nr_wait = (int) iowq.cq_tail -
READ_ONCE(ctx->rings->cq.tail);
else
nr_wait = 1;
if (ctx->flags & IORING_SETUP_DEFER_TASKRUN) {
atomic_set(&ctx->cq_wait_nr, nr_wait);
set_current_state(TASK_INTERRUPTIBLE);
} else {
prepare_to_wait_exclusive(&ctx->cq_wait, &iowq.wq,
TASK_INTERRUPTIBLE);
}
ret = io_cqring_wait_schedule(ctx, &iowq, ext_arg, start_time);
__set_current_state(TASK_RUNNING);
atomic_set(&ctx->cq_wait_nr, IO_CQ_WAKE_INIT);
/*
* Run task_work after scheduling and before io_should_wake().
* If we got woken because of task_work being processed, run it
* now rather than let the caller do another wait loop.
*/
if (io_local_work_pending(ctx))
io_run_local_work(ctx, nr_wait, nr_wait);
io_run_task_work();
/*
* Non-local task_work will be run on exit to userspace, but
* if we're using DEFER_TASKRUN, then we could have waited
* with a timeout for a number of requests. If the timeout
* hits, we could have some requests ready to process. Ensure
* this break is _after_ we have run task_work, to avoid
* deferring running potentially pending requests until the
* next time we wait for events.
*/
if (ret < 0)
break;
check_cq = READ_ONCE(ctx->check_cq);
if (unlikely(check_cq)) {
/* let the caller flush overflows, retry */
if (check_cq & BIT(IO_CHECK_CQ_OVERFLOW_BIT))
io_cqring_do_overflow_flush(ctx);
if (check_cq & BIT(IO_CHECK_CQ_DROPPED_BIT)) {
ret = -EBADR;
break;
}
}
if (io_should_wake(&iowq)) {
ret = 0;
break;
}
cond_resched();
} while (1);
if (!(ctx->flags & IORING_SETUP_DEFER_TASKRUN))
finish_wait(&ctx->cq_wait, &iowq.wq);
restore_saved_sigmask_unless(ret == -EINTR);
return READ_ONCE(rings->cq.head) == READ_ONCE(rings->cq.tail) ? ret : 0;
}
static void io_rings_free(struct io_ring_ctx *ctx)
{
io_free_region(ctx, &ctx->sq_region);
io_free_region(ctx, &ctx->ring_region);
ctx->rings = NULL;
ctx->sq_sqes = NULL;
}
unsigned long rings_size(unsigned int flags, unsigned int sq_entries,
unsigned int cq_entries, size_t *sq_offset)
{
struct io_rings *rings;
size_t off, sq_array_size;
off = struct_size(rings, cqes, cq_entries);
if (off == SIZE_MAX)
return SIZE_MAX;
if (flags & IORING_SETUP_CQE32) {
if (check_shl_overflow(off, 1, &off))
return SIZE_MAX;
}
if (flags & IORING_SETUP_CQE_MIXED) {
if (cq_entries < 2)
return SIZE_MAX;
}
#ifdef CONFIG_SMP
off = ALIGN(off, SMP_CACHE_BYTES);
if (off == 0)
return SIZE_MAX;
#endif
if (flags & IORING_SETUP_NO_SQARRAY) {
*sq_offset = SIZE_MAX;
return off;
}
*sq_offset = off;
sq_array_size = array_size(sizeof(u32), sq_entries);
if (sq_array_size == SIZE_MAX)
return SIZE_MAX;
if (check_add_overflow(off, sq_array_size, &off))
return SIZE_MAX;
return off;
}
static __cold void __io_req_caches_free(struct io_ring_ctx *ctx)
{
struct io_kiocb *req;
int nr = 0;
while (!io_req_cache_empty(ctx)) {
req = io_extract_req(ctx);
io_poison_req(req);
kmem_cache_free(req_cachep, req);
nr++;
}
if (nr) {
ctx->nr_req_allocated -= nr;
percpu_ref_put_many(&ctx->refs, nr);
}
}
static __cold void io_req_caches_free(struct io_ring_ctx *ctx)
{
guard(mutex)(&ctx->uring_lock);
__io_req_caches_free(ctx);
}
static __cold void io_ring_ctx_free(struct io_ring_ctx *ctx)
{
io_sq_thread_finish(ctx);
mutex_lock(&ctx->uring_lock);
io_sqe_buffers_unregister(ctx);
io_sqe_files_unregister(ctx);
io_unregister_zcrx_ifqs(ctx);
io_cqring_overflow_kill(ctx);
io_eventfd_unregister(ctx);
io_free_alloc_caches(ctx);
io_destroy_buffers(ctx);
io_free_region(ctx, &ctx->param_region);
mutex_unlock(&ctx->uring_lock);
if (ctx->sq_creds)
put_cred(ctx->sq_creds);
if (ctx->submitter_task)
put_task_struct(ctx->submitter_task);
WARN_ON_ONCE(!list_empty(&ctx->ltimeout_list));
if (ctx->mm_account) {
mmdrop(ctx->mm_account);
ctx->mm_account = NULL;
}
io_rings_free(ctx);
if (!(ctx->flags & IORING_SETUP_NO_SQARRAY))
static_branch_dec(&io_key_has_sqarray);
percpu_ref_exit(&ctx->refs);
free_uid(ctx->user);
io_req_caches_free(ctx);
WARN_ON_ONCE(ctx->nr_req_allocated);
if (ctx->hash_map)
io_wq_put_hash(ctx->hash_map);
io_napi_free(ctx);
kvfree(ctx->cancel_table.hbs);
xa_destroy(&ctx->io_bl_xa);
kfree(ctx);
}
static __cold void io_activate_pollwq_cb(struct callback_head *cb)
{
struct io_ring_ctx *ctx = container_of(cb, struct io_ring_ctx,
poll_wq_task_work);
mutex_lock(&ctx->uring_lock);
ctx->poll_activated = true;
mutex_unlock(&ctx->uring_lock);
/*
* Wake ups for some events between start of polling and activation
* might've been lost due to loose synchronisation.
*/
wake_up_all(&ctx->poll_wq);
percpu_ref_put(&ctx->refs);
}
__cold void io_activate_pollwq(struct io_ring_ctx *ctx)
{
spin_lock(&ctx->completion_lock);
/* already activated or in progress */
if (ctx->poll_activated || ctx->poll_wq_task_work.func)
goto out;
if (WARN_ON_ONCE(!ctx->task_complete))
goto out;
if (!ctx->submitter_task)
goto out;
/*
* with ->submitter_task only the submitter task completes requests, we
* only need to sync with it, which is done by injecting a tw
*/
init_task_work(&ctx->poll_wq_task_work, io_activate_pollwq_cb);
percpu_ref_get(&ctx->refs);
if (task_work_add(ctx->submitter_task, &ctx->poll_wq_task_work, TWA_SIGNAL))
percpu_ref_put(&ctx->refs);
out:
spin_unlock(&ctx->completion_lock);
}
static __poll_t io_uring_poll(struct file *file, poll_table *wait)
{
struct io_ring_ctx *ctx = file->private_data;
__poll_t mask = 0;
if (unlikely(!ctx->poll_activated))
io_activate_pollwq(ctx);
/*
* provides mb() which pairs with barrier from wq_has_sleeper
* call in io_commit_cqring
*/
poll_wait(file, &ctx->poll_wq, wait);
if (!io_sqring_full(ctx))
mask |= EPOLLOUT | EPOLLWRNORM;
/*
* Don't flush cqring overflow list here, just do a simple check.
* Otherwise there could possible be ABBA deadlock:
* CPU0 CPU1
* ---- ----
* lock(&ctx->uring_lock);
* lock(&ep->mtx);
* lock(&ctx->uring_lock);
* lock(&ep->mtx);
*
* Users may get EPOLLIN meanwhile seeing nothing in cqring, this
* pushes them to do the flush.
*/
if (__io_cqring_events_user(ctx) || io_has_work(ctx))
mask |= EPOLLIN | EPOLLRDNORM;
return mask;
}
struct io_tctx_exit {
struct callback_head task_work;
struct completion completion;
struct io_ring_ctx *ctx;
};
static __cold void io_tctx_exit_cb(struct callback_head *cb)
{
struct io_uring_task *tctx = current->io_uring;
struct io_tctx_exit *work;
work = container_of(cb, struct io_tctx_exit, task_work);
/*
* When @in_cancel, we're in cancellation and it's racy to remove the
* node. It'll be removed by the end of cancellation, just ignore it.
* tctx can be NULL if the queueing of this task_work raced with
* work cancelation off the exec path.
*/
if (tctx && !atomic_read(&tctx->in_cancel))
io_uring_del_tctx_node((unsigned long)work->ctx);
complete(&work->completion);
}
static __cold bool io_cancel_ctx_cb(struct io_wq_work *work, void *data)
{
struct io_kiocb *req = container_of(work, struct io_kiocb, work);
return req->ctx == data;
}
static __cold void io_ring_exit_work(struct work_struct *work)
{
struct io_ring_ctx *ctx = container_of(work, struct io_ring_ctx, exit_work);
unsigned long timeout = jiffies + HZ * 60 * 5;
unsigned long interval = HZ / 20;
struct io_tctx_exit exit;
struct io_tctx_node *node;
int ret;
/*
* If we're doing polled IO and end up having requests being
* submitted async (out-of-line), then completions can come in while
* we're waiting for refs to drop. We need to reap these manually,
* as nobody else will be looking for them.
*/
do {
if (test_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq)) {
mutex_lock(&ctx->uring_lock);
io_cqring_overflow_kill(ctx);
mutex_unlock(&ctx->uring_lock);
}
if (!xa_empty(&ctx->zcrx_ctxs)) {
mutex_lock(&ctx->uring_lock);
io_shutdown_zcrx_ifqs(ctx);
mutex_unlock(&ctx->uring_lock);
}
if (ctx->flags & IORING_SETUP_DEFER_TASKRUN)
io_move_task_work_from_local(ctx);
/* The SQPOLL thread never reaches this path */
while (io_uring_try_cancel_requests(ctx, NULL, true, false))
cond_resched();
if (ctx->sq_data) {
struct io_sq_data *sqd = ctx->sq_data;
struct task_struct *tsk;
io_sq_thread_park(sqd);
tsk = sqpoll_task_locked(sqd);
if (tsk && tsk->io_uring && tsk->io_uring->io_wq)
io_wq_cancel_cb(tsk->io_uring->io_wq,
io_cancel_ctx_cb, ctx, true);
io_sq_thread_unpark(sqd);
}
io_req_caches_free(ctx);
if (WARN_ON_ONCE(time_after(jiffies, timeout))) {
/* there is little hope left, don't run it too often */
interval = HZ * 60;
}
/*
* This is really an uninterruptible wait, as it has to be
* complete. But it's also run from a kworker, which doesn't
* take signals, so it's fine to make it interruptible. This
* avoids scenarios where we knowingly can wait much longer
* on completions, for example if someone does a SIGSTOP on
* a task that needs to finish task_work to make this loop
* complete. That's a synthetic situation that should not
* cause a stuck task backtrace, and hence a potential panic
* on stuck tasks if that is enabled.
*/
} while (!wait_for_completion_interruptible_timeout(&ctx->ref_comp, interval));
init_completion(&exit.completion);
init_task_work(&exit.task_work, io_tctx_exit_cb);
exit.ctx = ctx;
mutex_lock(&ctx->uring_lock);
while (!list_empty(&ctx->tctx_list)) {
WARN_ON_ONCE(time_after(jiffies, timeout));
node = list_first_entry(&ctx->tctx_list, struct io_tctx_node,
ctx_node);
/* don't spin on a single task if cancellation failed */
list_rotate_left(&ctx->tctx_list);
ret = task_work_add(node->task, &exit.task_work, TWA_SIGNAL);
if (WARN_ON_ONCE(ret))
continue;
mutex_unlock(&ctx->uring_lock);
/*
* See comment above for
* wait_for_completion_interruptible_timeout() on why this
* wait is marked as interruptible.
*/
wait_for_completion_interruptible(&exit.completion);
mutex_lock(&ctx->uring_lock);
}
mutex_unlock(&ctx->uring_lock);
spin_lock(&ctx->completion_lock);
spin_unlock(&ctx->completion_lock);
/* pairs with RCU read section in io_req_local_work_add() */
if (ctx->flags & IORING_SETUP_DEFER_TASKRUN)
synchronize_rcu();
io_ring_ctx_free(ctx);
}
static __cold void io_ring_ctx_wait_and_kill(struct io_ring_ctx *ctx)
{
unsigned long index;
struct creds *creds;
mutex_lock(&ctx->uring_lock);
percpu_ref_kill(&ctx->refs);
xa_for_each(&ctx->personalities, index, creds)
io_unregister_personality(ctx, index);
mutex_unlock(&ctx->uring_lock);
flush_delayed_work(&ctx->fallback_work);
INIT_WORK(&ctx->exit_work, io_ring_exit_work);
/*
* Use system_dfl_wq to avoid spawning tons of event kworkers
* if we're exiting a ton of rings at the same time. It just adds
* noise and overhead, there's no discernable change in runtime
* over using system_percpu_wq.
*/
queue_work(iou_wq, &ctx->exit_work);
}
static int io_uring_release(struct inode *inode, struct file *file)
{
struct io_ring_ctx *ctx = file->private_data;
file->private_data = NULL;
io_ring_ctx_wait_and_kill(ctx);
return 0;
}
struct io_task_cancel {
struct io_uring_task *tctx;
bool all;
};
static bool io_cancel_task_cb(struct io_wq_work *work, void *data)
{
struct io_kiocb *req = container_of(work, struct io_kiocb, work);
struct io_task_cancel *cancel = data;
return io_match_task_safe(req, cancel->tctx, cancel->all);
}
static __cold bool io_cancel_defer_files(struct io_ring_ctx *ctx,
struct io_uring_task *tctx,
bool cancel_all)
{
struct io_defer_entry *de;
LIST_HEAD(list);
list_for_each_entry_reverse(de, &ctx->defer_list, list) {
if (io_match_task_safe(de->req, tctx, cancel_all)) {
list_cut_position(&list, &ctx->defer_list, &de->list);
break;
}
}
if (list_empty(&list))
return false;
while (!list_empty(&list)) {
de = list_first_entry(&list, struct io_defer_entry, list);
list_del_init(&de->list);
ctx->nr_drained -= io_linked_nr(de->req);
io_req_task_queue_fail(de->req, -ECANCELED);
kfree(de);
}
return true;
}
static __cold bool io_uring_try_cancel_iowq(struct io_ring_ctx *ctx)
{
struct io_tctx_node *node;
enum io_wq_cancel cret;
bool ret = false;
mutex_lock(&ctx->uring_lock);
list_for_each_entry(node, &ctx->tctx_list, ctx_node) {
struct io_uring_task *tctx = node->task->io_uring;
/*
* io_wq will stay alive while we hold uring_lock, because it's
* killed after ctx nodes, which requires to take the lock.
*/
if (!tctx || !tctx->io_wq)
continue;
cret = io_wq_cancel_cb(tctx->io_wq, io_cancel_ctx_cb, ctx, true);
ret |= (cret != IO_WQ_CANCEL_NOTFOUND);
}
mutex_unlock(&ctx->uring_lock);
return ret;
}
static __cold bool io_uring_try_cancel_requests(struct io_ring_ctx *ctx,
struct io_uring_task *tctx,
bool cancel_all,
bool is_sqpoll_thread)
{
struct io_task_cancel cancel = { .tctx = tctx, .all = cancel_all, };
enum io_wq_cancel cret;
bool ret = false;
/* set it so io_req_local_work_add() would wake us up */
if (ctx->flags & IORING_SETUP_DEFER_TASKRUN) {
atomic_set(&ctx->cq_wait_nr, 1);
smp_mb();
}
/* failed during ring init, it couldn't have issued any requests */
if (!ctx->rings)
return false;
if (!tctx) {
ret |= io_uring_try_cancel_iowq(ctx);
} else if (tctx->io_wq) {
/*
* Cancels requests of all rings, not only @ctx, but
* it's fine as the task is in exit/exec.
*/
cret = io_wq_cancel_cb(tctx->io_wq, io_cancel_task_cb,
&cancel, true);
ret |= (cret != IO_WQ_CANCEL_NOTFOUND);
}
/* SQPOLL thread does its own polling */
if ((!(ctx->flags & IORING_SETUP_SQPOLL) && cancel_all) ||
is_sqpoll_thread) {
while (!wq_list_empty(&ctx->iopoll_list)) {
io_iopoll_try_reap_events(ctx);
ret = true;
cond_resched();
}
}
if ((ctx->flags & IORING_SETUP_DEFER_TASKRUN) &&
io_allowed_defer_tw_run(ctx))
ret |= io_run_local_work(ctx, INT_MAX, INT_MAX) > 0;
mutex_lock(&ctx->uring_lock);
ret |= io_cancel_defer_files(ctx, tctx, cancel_all);
ret |= io_poll_remove_all(ctx, tctx, cancel_all);
ret |= io_waitid_remove_all(ctx, tctx, cancel_all);
ret |= io_futex_remove_all(ctx, tctx, cancel_all);
ret |= io_uring_try_cancel_uring_cmd(ctx, tctx, cancel_all);
mutex_unlock(&ctx->uring_lock);
ret |= io_kill_timeouts(ctx, tctx, cancel_all);
if (tctx)
ret |= io_run_task_work() > 0;
else
ret |= flush_delayed_work(&ctx->fallback_work);
return ret;
}
static s64 tctx_inflight(struct io_uring_task *tctx, bool tracked)
{
if (tracked)
return atomic_read(&tctx->inflight_tracked);
return percpu_counter_sum(&tctx->inflight);
}
/*
* Find any io_uring ctx that this task has registered or done IO on, and cancel
* requests. @sqd should be not-null IFF it's an SQPOLL thread cancellation.
*/
__cold void io_uring_cancel_generic(bool cancel_all, struct io_sq_data *sqd)
{
struct io_uring_task *tctx = current->io_uring;
struct io_ring_ctx *ctx;
struct io_tctx_node *node;
unsigned long index;
s64 inflight;
DEFINE_WAIT(wait);
WARN_ON_ONCE(sqd && sqpoll_task_locked(sqd) != current);
if (!current->io_uring)
return;
if (tctx->io_wq)
io_wq_exit_start(tctx->io_wq);
atomic_inc(&tctx->in_cancel);
do {
bool loop = false;
io_uring_drop_tctx_refs(current);
if (!tctx_inflight(tctx, !cancel_all))
break;
/* read completions before cancelations */
inflight = tctx_inflight(tctx, false);
if (!inflight)
break;
if (!sqd) {
xa_for_each(&tctx->xa, index, node) {
/* sqpoll task will cancel all its requests */
if (node->ctx->sq_data)
continue;
loop |= io_uring_try_cancel_requests(node->ctx,
current->io_uring,
cancel_all,
false);
}
} else {
list_for_each_entry(ctx, &sqd->ctx_list, sqd_list)
loop |= io_uring_try_cancel_requests(ctx,
current->io_uring,
cancel_all,
true);
}
if (loop) {
cond_resched();
continue;
}
prepare_to_wait(&tctx->wait, &wait, TASK_INTERRUPTIBLE);
io_run_task_work();
io_uring_drop_tctx_refs(current);
xa_for_each(&tctx->xa, index, node) {
if (io_local_work_pending(node->ctx)) {
WARN_ON_ONCE(node->ctx->submitter_task &&
node->ctx->submitter_task != current);
goto end_wait;
}
}
/*
* If we've seen completions, retry without waiting. This
* avoids a race where a completion comes in before we did
* prepare_to_wait().
*/
if (inflight == tctx_inflight(tctx, !cancel_all))
schedule();
end_wait:
finish_wait(&tctx->wait, &wait);
} while (1);
io_uring_clean_tctx(tctx);
if (cancel_all) {
/*
* We shouldn't run task_works after cancel, so just leave
* ->in_cancel set for normal exit.
*/
atomic_dec(&tctx->in_cancel);
/* for exec all current's requests should be gone, kill tctx */
__io_uring_free(current);
}
}
void __io_uring_cancel(bool cancel_all)
{
io_uring_unreg_ringfd();
io_uring_cancel_generic(cancel_all, NULL);
}
static struct io_uring_reg_wait *io_get_ext_arg_reg(struct io_ring_ctx *ctx,
const struct io_uring_getevents_arg __user *uarg)
{
unsigned long size = sizeof(struct io_uring_reg_wait);
unsigned long offset = (uintptr_t)uarg;
unsigned long end;
if (unlikely(offset % sizeof(long)))
return ERR_PTR(-EFAULT);
/* also protects from NULL ->cq_wait_arg as the size would be 0 */
if (unlikely(check_add_overflow(offset, size, &end) ||
end > ctx->cq_wait_size))
return ERR_PTR(-EFAULT);
offset = array_index_nospec(offset, ctx->cq_wait_size - size);
return ctx->cq_wait_arg + offset;
}
static int io_validate_ext_arg(struct io_ring_ctx *ctx, unsigned flags,
const void __user *argp, size_t argsz)
{
struct io_uring_getevents_arg arg;
if (!(flags & IORING_ENTER_EXT_ARG))
return 0;
if (flags & IORING_ENTER_EXT_ARG_REG)
return -EINVAL;
if (argsz != sizeof(arg))
return -EINVAL;
if (copy_from_user(&arg, argp, sizeof(arg)))
return -EFAULT;
return 0;
}
static int io_get_ext_arg(struct io_ring_ctx *ctx, unsigned flags,
const void __user *argp, struct ext_arg *ext_arg)
{
const struct io_uring_getevents_arg __user *uarg = argp;
struct io_uring_getevents_arg arg;
ext_arg->iowait = !(flags & IORING_ENTER_NO_IOWAIT);
/*
* If EXT_ARG isn't set, then we have no timespec and the argp pointer
* is just a pointer to the sigset_t.
*/
if (!(flags & IORING_ENTER_EXT_ARG)) {
ext_arg->sig = (const sigset_t __user *) argp;
return 0;
}
if (flags & IORING_ENTER_EXT_ARG_REG) {
struct io_uring_reg_wait *w;
if (ext_arg->argsz != sizeof(struct io_uring_reg_wait))
return -EINVAL;
w = io_get_ext_arg_reg(ctx, argp);
if (IS_ERR(w))
return PTR_ERR(w);
if (w->flags & ~IORING_REG_WAIT_TS)
return -EINVAL;
ext_arg->min_time = READ_ONCE(w->min_wait_usec) * NSEC_PER_USEC;
ext_arg->sig = u64_to_user_ptr(READ_ONCE(w->sigmask));
ext_arg->argsz = READ_ONCE(w->sigmask_sz);
if (w->flags & IORING_REG_WAIT_TS) {
ext_arg->ts.tv_sec = READ_ONCE(w->ts.tv_sec);
ext_arg->ts.tv_nsec = READ_ONCE(w->ts.tv_nsec);
ext_arg->ts_set = true;
}
return 0;
}
/*
* EXT_ARG is set - ensure we agree on the size of it and copy in our
* timespec and sigset_t pointers if good.
*/
if (ext_arg->argsz != sizeof(arg))
return -EINVAL;
#ifdef CONFIG_64BIT
if (!user_access_begin(uarg, sizeof(*uarg)))
return -EFAULT;
unsafe_get_user(arg.sigmask, &uarg->sigmask, uaccess_end);
unsafe_get_user(arg.sigmask_sz, &uarg->sigmask_sz, uaccess_end);
unsafe_get_user(arg.min_wait_usec, &uarg->min_wait_usec, uaccess_end);
unsafe_get_user(arg.ts, &uarg->ts, uaccess_end);
user_access_end();
#else
if (copy_from_user(&arg, uarg, sizeof(arg)))
return -EFAULT;
#endif
ext_arg->min_time = arg.min_wait_usec * NSEC_PER_USEC;
ext_arg->sig = u64_to_user_ptr(arg.sigmask);
ext_arg->argsz = arg.sigmask_sz;
if (arg.ts) {
if (get_timespec64(&ext_arg->ts, u64_to_user_ptr(arg.ts)))
return -EFAULT;
ext_arg->ts_set = true;
}
return 0;
#ifdef CONFIG_64BIT
uaccess_end:
user_access_end();
return -EFAULT;
#endif
}
SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit,
u32, min_complete, u32, flags, const void __user *, argp,
size_t, argsz)
{
struct io_ring_ctx *ctx;
struct file *file;
long ret;
if (unlikely(flags & ~IORING_ENTER_FLAGS))
return -EINVAL;
/*
* Ring fd has been registered via IORING_REGISTER_RING_FDS, we
* need only dereference our task private array to find it.
*/
if (flags & IORING_ENTER_REGISTERED_RING) {
struct io_uring_task *tctx = current->io_uring;
if (unlikely(!tctx || fd >= IO_RINGFD_REG_MAX))
return -EINVAL;
fd = array_index_nospec(fd, IO_RINGFD_REG_MAX);
file = tctx->registered_rings[fd];
if (unlikely(!file))
return -EBADF;
} else {
file = fget(fd);
if (unlikely(!file))
return -EBADF;
ret = -EOPNOTSUPP;
if (unlikely(!io_is_uring_fops(file)))
goto out;
}
ctx = file->private_data;
ret = -EBADFD;
if (unlikely(ctx->flags & IORING_SETUP_R_DISABLED))
goto out;
/*
* For SQ polling, the thread will do all submissions and completions.
* Just return the requested submit count, and wake the thread if
* we were asked to.
*/
ret = 0;
if (ctx->flags & IORING_SETUP_SQPOLL) {
if (unlikely(ctx->sq_data->thread == NULL)) {
ret = -EOWNERDEAD;
goto out;
}
if (flags & IORING_ENTER_SQ_WAKEUP)
wake_up(&ctx->sq_data->wait);
if (flags & IORING_ENTER_SQ_WAIT)
io_sqpoll_wait_sq(ctx);
ret = to_submit;
} else if (to_submit) {
ret = io_uring_add_tctx_node(ctx);
if (unlikely(ret))
goto out;
mutex_lock(&ctx->uring_lock);
ret = io_submit_sqes(ctx, to_submit);
if (ret != to_submit) {
mutex_unlock(&ctx->uring_lock);
goto out;
}
if (flags & IORING_ENTER_GETEVENTS) {
if (ctx->syscall_iopoll)
goto iopoll_locked;
/*
* Ignore errors, we'll soon call io_cqring_wait() and
* it should handle ownership problems if any.
*/
if (ctx->flags & IORING_SETUP_DEFER_TASKRUN)
(void)io_run_local_work_locked(ctx, min_complete);
}
mutex_unlock(&ctx->uring_lock);
}
if (flags & IORING_ENTER_GETEVENTS) {
int ret2;
if (ctx->syscall_iopoll) {
/*
* We disallow the app entering submit/complete with
* polling, but we still need to lock the ring to
* prevent racing with polled issue that got punted to
* a workqueue.
*/
mutex_lock(&ctx->uring_lock);
iopoll_locked:
ret2 = io_validate_ext_arg(ctx, flags, argp, argsz);
if (likely(!ret2))
ret2 = io_iopoll_check(ctx, min_complete);
mutex_unlock(&ctx->uring_lock);
} else {
struct ext_arg ext_arg = { .argsz = argsz };
ret2 = io_get_ext_arg(ctx, flags, argp, &ext_arg);
if (likely(!ret2))
ret2 = io_cqring_wait(ctx, min_complete, flags,
&ext_arg);
}
if (!ret) {
ret = ret2;
/*
* EBADR indicates that one or more CQE were dropped.
* Once the user has been informed we can clear the bit
* as they are obviously ok with those drops.
*/
if (unlikely(ret2 == -EBADR))
clear_bit(IO_CHECK_CQ_DROPPED_BIT,
&ctx->check_cq);
}
}
out:
if (!(flags & IORING_ENTER_REGISTERED_RING))
fput(file);
return ret;
}
static const struct file_operations io_uring_fops = {
.release = io_uring_release,
.mmap = io_uring_mmap,
.get_unmapped_area = io_uring_get_unmapped_area,
#ifndef CONFIG_MMU
.mmap_capabilities = io_uring_nommu_mmap_capabilities,
#endif
.poll = io_uring_poll,
#ifdef CONFIG_PROC_FS
.show_fdinfo = io_uring_show_fdinfo,
#endif
};
bool io_is_uring_fops(struct file *file)
{
return file->f_op == &io_uring_fops;
}
static __cold int io_allocate_scq_urings(struct io_ring_ctx *ctx,
struct io_uring_params *p)
{
struct io_uring_region_desc rd;
struct io_rings *rings;
size_t size, sq_array_offset;
int ret;
/* make sure these are sane, as we already accounted them */
ctx->sq_entries = p->sq_entries;
ctx->cq_entries = p->cq_entries;
size = rings_size(ctx->flags, p->sq_entries, p->cq_entries,
&sq_array_offset);
if (size == SIZE_MAX)
return -EOVERFLOW;
memset(&rd, 0, sizeof(rd));
rd.size = PAGE_ALIGN(size);
if (ctx->flags & IORING_SETUP_NO_MMAP) {
rd.user_addr = p->cq_off.user_addr;
rd.flags |= IORING_MEM_REGION_TYPE_USER;
}
ret = io_create_region(ctx, &ctx->ring_region, &rd, IORING_OFF_CQ_RING);
if (ret)
return ret;
ctx->rings = rings = io_region_get_ptr(&ctx->ring_region);
if (!(ctx->flags & IORING_SETUP_NO_SQARRAY))
ctx->sq_array = (u32 *)((char *)rings + sq_array_offset);
rings->sq_ring_mask = p->sq_entries - 1;
rings->cq_ring_mask = p->cq_entries - 1;
rings->sq_ring_entries = p->sq_entries;
rings->cq_ring_entries = p->cq_entries;
if (p->flags & IORING_SETUP_SQE128)
size = array_size(2 * sizeof(struct io_uring_sqe), p->sq_entries);
else
size = array_size(sizeof(struct io_uring_sqe), p->sq_entries);
if (size == SIZE_MAX) {
io_rings_free(ctx);
return -EOVERFLOW;
}
memset(&rd, 0, sizeof(rd));
rd.size = PAGE_ALIGN(size);
if (ctx->flags & IORING_SETUP_NO_MMAP) {
rd.user_addr = p->sq_off.user_addr;
rd.flags |= IORING_MEM_REGION_TYPE_USER;
}
ret = io_create_region(ctx, &ctx->sq_region, &rd, IORING_OFF_SQES);
if (ret) {
io_rings_free(ctx);
return ret;
}
ctx->sq_sqes = io_region_get_ptr(&ctx->sq_region);
return 0;
}
static int io_uring_install_fd(struct file *file)
{
int fd;
fd = get_unused_fd_flags(O_RDWR | O_CLOEXEC);
if (fd < 0)
return fd;
fd_install(fd, file);
return fd;
}
/*
* Allocate an anonymous fd, this is what constitutes the application
* visible backing of an io_uring instance. The application mmaps this
* fd to gain access to the SQ/CQ ring details.
*/
static struct file *io_uring_get_file(struct io_ring_ctx *ctx)
{
/* Create a new inode so that the LSM can block the creation. */
return anon_inode_create_getfile("[io_uring]", &io_uring_fops, ctx,
O_RDWR | O_CLOEXEC, NULL);
}
static int io_uring_sanitise_params(struct io_uring_params *p)
{
unsigned flags = p->flags;
/* There is no way to mmap rings without a real fd */
if ((flags & IORING_SETUP_REGISTERED_FD_ONLY) &&
!(flags & IORING_SETUP_NO_MMAP))
return -EINVAL;
if (flags & IORING_SETUP_SQPOLL) {
/* IPI related flags don't make sense with SQPOLL */
if (flags & (IORING_SETUP_COOP_TASKRUN |
IORING_SETUP_TASKRUN_FLAG |
IORING_SETUP_DEFER_TASKRUN))
return -EINVAL;
}
if (flags & IORING_SETUP_TASKRUN_FLAG) {
if (!(flags & (IORING_SETUP_COOP_TASKRUN |
IORING_SETUP_DEFER_TASKRUN)))
return -EINVAL;
}
/* HYBRID_IOPOLL only valid with IOPOLL */
if ((flags & IORING_SETUP_HYBRID_IOPOLL) && !(flags & IORING_SETUP_IOPOLL))
return -EINVAL;
/*
* For DEFER_TASKRUN we require the completion task to be the same as
* the submission task. This implies that there is only one submitter.
*/
if ((flags & IORING_SETUP_DEFER_TASKRUN) &&
!(flags & IORING_SETUP_SINGLE_ISSUER))
return -EINVAL;
/*
* Nonsensical to ask for CQE32 and mixed CQE support, it's not
* supported to post 16b CQEs on a ring setup with CQE32.
*/
if ((flags & (IORING_SETUP_CQE32|IORING_SETUP_CQE_MIXED)) ==
(IORING_SETUP_CQE32|IORING_SETUP_CQE_MIXED))
return -EINVAL;
return 0;
}
int io_uring_fill_params(unsigned entries, struct io_uring_params *p)
{
if (!entries)
return -EINVAL;
if (entries > IORING_MAX_ENTRIES) {
if (!(p->flags & IORING_SETUP_CLAMP))
return -EINVAL;
entries = IORING_MAX_ENTRIES;
}
/*
* Use twice as many entries for the CQ ring. It's possible for the
* application to drive a higher depth than the size of the SQ ring,
* since the sqes are only used at submission time. This allows for
* some flexibility in overcommitting a bit. If the application has
* set IORING_SETUP_CQSIZE, it will have passed in the desired number
* of CQ ring entries manually.
*/
p->sq_entries = roundup_pow_of_two(entries);
if (p->flags & IORING_SETUP_CQSIZE) {
/*
* If IORING_SETUP_CQSIZE is set, we do the same roundup
* to a power-of-two, if it isn't already. We do NOT impose
* any cq vs sq ring sizing.
*/
if (!p->cq_entries)
return -EINVAL;
if (p->cq_entries > IORING_MAX_CQ_ENTRIES) {
if (!(p->flags & IORING_SETUP_CLAMP))
return -EINVAL;
p->cq_entries = IORING_MAX_CQ_ENTRIES;
}
p->cq_entries = roundup_pow_of_two(p->cq_entries);
if (p->cq_entries < p->sq_entries)
return -EINVAL;
} else {
p->cq_entries = 2 * p->sq_entries;
}
p->sq_off.head = offsetof(struct io_rings, sq.head);
p->sq_off.tail = offsetof(struct io_rings, sq.tail);
p->sq_off.ring_mask = offsetof(struct io_rings, sq_ring_mask);
p->sq_off.ring_entries = offsetof(struct io_rings, sq_ring_entries);
p->sq_off.flags = offsetof(struct io_rings, sq_flags);
p->sq_off.dropped = offsetof(struct io_rings, sq_dropped);
p->sq_off.resv1 = 0;
if (!(p->flags & IORING_SETUP_NO_MMAP))
p->sq_off.user_addr = 0;
p->cq_off.head = offsetof(struct io_rings, cq.head);
p->cq_off.tail = offsetof(struct io_rings, cq.tail);
p->cq_off.ring_mask = offsetof(struct io_rings, cq_ring_mask);
p->cq_off.ring_entries = offsetof(struct io_rings, cq_ring_entries);
p->cq_off.overflow = offsetof(struct io_rings, cq_overflow);
p->cq_off.cqes = offsetof(struct io_rings, cqes);
p->cq_off.flags = offsetof(struct io_rings, cq_flags);
p->cq_off.resv1 = 0;
if (!(p->flags & IORING_SETUP_NO_MMAP))
p->cq_off.user_addr = 0;
return 0;
}
static __cold int io_uring_create(unsigned entries, struct io_uring_params *p,
struct io_uring_params __user *params)
{
struct io_ring_ctx *ctx;
struct io_uring_task *tctx;
struct file *file;
int ret;
ret = io_uring_sanitise_params(p);
if (ret)
return ret;
ret = io_uring_fill_params(entries, p);
if (unlikely(ret))
return ret;
ctx = io_ring_ctx_alloc(p);
if (!ctx)
return -ENOMEM;
ctx->clockid = CLOCK_MONOTONIC;
ctx->clock_offset = 0;
if (!(ctx->flags & IORING_SETUP_NO_SQARRAY))
static_branch_inc(&io_key_has_sqarray);
if ((ctx->flags & IORING_SETUP_DEFER_TASKRUN) &&
!(ctx->flags & IORING_SETUP_IOPOLL) &&
!(ctx->flags & IORING_SETUP_SQPOLL))
ctx->task_complete = true;
if (ctx->task_complete || (ctx->flags & IORING_SETUP_IOPOLL))
ctx->lockless_cq = true;
/*
* lazy poll_wq activation relies on ->task_complete for synchronisation
* purposes, see io_activate_pollwq()
*/
if (!ctx->task_complete)
ctx->poll_activated = true;
/*
* When SETUP_IOPOLL and SETUP_SQPOLL are both enabled, user
* space applications don't need to do io completion events
* polling again, they can rely on io_sq_thread to do polling
* work, which can reduce cpu usage and uring_lock contention.
*/
if (ctx->flags & IORING_SETUP_IOPOLL &&
!(ctx->flags & IORING_SETUP_SQPOLL))
ctx->syscall_iopoll = 1;
ctx->compat = in_compat_syscall();
if (!ns_capable_noaudit(&init_user_ns, CAP_IPC_LOCK))
ctx->user = get_uid(current_user());
/*
* For SQPOLL, we just need a wakeup, always. For !SQPOLL, if
* COOP_TASKRUN is set, then IPIs are never needed by the app.
*/
if (ctx->flags & (IORING_SETUP_SQPOLL|IORING_SETUP_COOP_TASKRUN))
ctx->notify_method = TWA_SIGNAL_NO_IPI;
else
ctx->notify_method = TWA_SIGNAL;
/*
* This is just grabbed for accounting purposes. When a process exits,
* the mm is exited and dropped before the files, hence we need to hang
* on to this mm purely for the purposes of being able to unaccount
* memory (locked/pinned vm). It's not used for anything else.
*/
mmgrab(current->mm);
ctx->mm_account = current->mm;
ret = io_allocate_scq_urings(ctx, p);
if (ret)
goto err;
if (!(p->flags & IORING_SETUP_NO_SQARRAY))
p->sq_off.array = (char *)ctx->sq_array - (char *)ctx->rings;
ret = io_sq_offload_create(ctx, p);
if (ret)
goto err;
p->features = IORING_FEAT_FLAGS;
if (copy_to_user(params, p, sizeof(*p))) {
ret = -EFAULT;
goto err;
}
if (ctx->flags & IORING_SETUP_SINGLE_ISSUER
&& !(ctx->flags & IORING_SETUP_R_DISABLED)) {
/*
* Unlike io_register_enable_rings(), don't need WRITE_ONCE()
* since ctx isn't yet accessible from other tasks
*/
ctx->submitter_task = get_task_struct(current);
}
file = io_uring_get_file(ctx);
if (IS_ERR(file)) {
ret = PTR_ERR(file);
goto err;
}
ret = __io_uring_add_tctx_node(ctx);
if (ret)
goto err_fput;
tctx = current->io_uring;
/*
* Install ring fd as the very last thing, so we don't risk someone
* having closed it before we finish setup
*/
if (p->flags & IORING_SETUP_REGISTERED_FD_ONLY)
ret = io_ring_add_registered_file(tctx, file, 0, IO_RINGFD_REG_MAX);
else
ret = io_uring_install_fd(file);
if (ret < 0)
goto err_fput;
trace_io_uring_create(ret, ctx, p->sq_entries, p->cq_entries, p->flags);
return ret;
err:
io_ring_ctx_wait_and_kill(ctx);
return ret;
err_fput:
fput(file);
return ret;
}
/*
* Sets up an aio uring context, and returns the fd. Applications asks for a
* ring size, we return the actual sq/cq ring sizes (among other things) in the
* params structure passed in.
*/
static long io_uring_setup(u32 entries, struct io_uring_params __user *params)
{
struct io_uring_params p;
int i;
if (copy_from_user(&p, params, sizeof(p)))
return -EFAULT;
for (i = 0; i < ARRAY_SIZE(p.resv); i++) {
if (p.resv[i])
return -EINVAL;
}
if (p.flags & ~IORING_SETUP_FLAGS)
return -EINVAL;
return io_uring_create(entries, &p, params);
}
static inline int io_uring_allowed(void)
{
int disabled = READ_ONCE(sysctl_io_uring_disabled);
kgid_t io_uring_group;
if (disabled == 2)
return -EPERM;
if (disabled == 0 || capable(CAP_SYS_ADMIN))
goto allowed_lsm;
io_uring_group = make_kgid(&init_user_ns, sysctl_io_uring_group);
if (!gid_valid(io_uring_group))
return -EPERM;
if (!in_group_p(io_uring_group))
return -EPERM;
allowed_lsm:
return security_uring_allowed();
}
SYSCALL_DEFINE2(io_uring_setup, u32, entries,
struct io_uring_params __user *, params)
{
int ret;
ret = io_uring_allowed();
if (ret)
return ret;
return io_uring_setup(entries, params);
}
static int __init io_uring_init(void)
{
struct kmem_cache_args kmem_args = {
.useroffset = offsetof(struct io_kiocb, cmd.data),
.usersize = sizeof_field(struct io_kiocb, cmd.data),
.freeptr_offset = offsetof(struct io_kiocb, work),
.use_freeptr_offset = true,
};
#define __BUILD_BUG_VERIFY_OFFSET_SIZE(stype, eoffset, esize, ename) do { \
BUILD_BUG_ON(offsetof(stype, ename) != eoffset); \
BUILD_BUG_ON(sizeof_field(stype, ename) != esize); \
} while (0)
#define BUILD_BUG_SQE_ELEM(eoffset, etype, ename) \
__BUILD_BUG_VERIFY_OFFSET_SIZE(struct io_uring_sqe, eoffset, sizeof(etype), ename)
#define BUILD_BUG_SQE_ELEM_SIZE(eoffset, esize, ename) \
__BUILD_BUG_VERIFY_OFFSET_SIZE(struct io_uring_sqe, eoffset, esize, ename)
BUILD_BUG_ON(sizeof(struct io_uring_sqe) != 64);
BUILD_BUG_SQE_ELEM(0, __u8, opcode);
BUILD_BUG_SQE_ELEM(1, __u8, flags);
BUILD_BUG_SQE_ELEM(2, __u16, ioprio);
BUILD_BUG_SQE_ELEM(4, __s32, fd);
BUILD_BUG_SQE_ELEM(8, __u64, off);
BUILD_BUG_SQE_ELEM(8, __u64, addr2);
BUILD_BUG_SQE_ELEM(8, __u32, cmd_op);
BUILD_BUG_SQE_ELEM(12, __u32, __pad1);
BUILD_BUG_SQE_ELEM(16, __u64, addr);
BUILD_BUG_SQE_ELEM(16, __u64, splice_off_in);
BUILD_BUG_SQE_ELEM(24, __u32, len);
BUILD_BUG_SQE_ELEM(28, __kernel_rwf_t, rw_flags);
BUILD_BUG_SQE_ELEM(28, /* compat */ int, rw_flags);
BUILD_BUG_SQE_ELEM(28, /* compat */ __u32, rw_flags);
BUILD_BUG_SQE_ELEM(28, __u32, fsync_flags);
BUILD_BUG_SQE_ELEM(28, /* compat */ __u16, poll_events);
BUILD_BUG_SQE_ELEM(28, __u32, poll32_events);
BUILD_BUG_SQE_ELEM(28, __u32, sync_range_flags);
BUILD_BUG_SQE_ELEM(28, __u32, msg_flags);
BUILD_BUG_SQE_ELEM(28, __u32, timeout_flags);
BUILD_BUG_SQE_ELEM(28, __u32, accept_flags);
BUILD_BUG_SQE_ELEM(28, __u32, cancel_flags);
BUILD_BUG_SQE_ELEM(28, __u32, open_flags);
BUILD_BUG_SQE_ELEM(28, __u32, statx_flags);
BUILD_BUG_SQE_ELEM(28, __u32, fadvise_advice);
BUILD_BUG_SQE_ELEM(28, __u32, splice_flags);
BUILD_BUG_SQE_ELEM(28, __u32, rename_flags);
BUILD_BUG_SQE_ELEM(28, __u32, unlink_flags);
BUILD_BUG_SQE_ELEM(28, __u32, hardlink_flags);
BUILD_BUG_SQE_ELEM(28, __u32, xattr_flags);
BUILD_BUG_SQE_ELEM(28, __u32, msg_ring_flags);
BUILD_BUG_SQE_ELEM(32, __u64, user_data);
BUILD_BUG_SQE_ELEM(40, __u16, buf_index);
BUILD_BUG_SQE_ELEM(40, __u16, buf_group);
BUILD_BUG_SQE_ELEM(42, __u16, personality);
BUILD_BUG_SQE_ELEM(44, __s32, splice_fd_in);
BUILD_BUG_SQE_ELEM(44, __u32, file_index);
BUILD_BUG_SQE_ELEM(44, __u16, addr_len);
BUILD_BUG_SQE_ELEM(44, __u8, write_stream);
BUILD_BUG_SQE_ELEM(45, __u8, __pad4[0]);
BUILD_BUG_SQE_ELEM(46, __u16, __pad3[0]);
BUILD_BUG_SQE_ELEM(48, __u64, addr3);
BUILD_BUG_SQE_ELEM_SIZE(48, 0, cmd);
BUILD_BUG_SQE_ELEM(48, __u64, attr_ptr);
BUILD_BUG_SQE_ELEM(56, __u64, attr_type_mask);
BUILD_BUG_SQE_ELEM(56, __u64, __pad2);
BUILD_BUG_ON(sizeof(struct io_uring_files_update) !=
sizeof(struct io_uring_rsrc_update));
BUILD_BUG_ON(sizeof(struct io_uring_rsrc_update) >
sizeof(struct io_uring_rsrc_update2));
/* ->buf_index is u16 */
BUILD_BUG_ON(offsetof(struct io_uring_buf_ring, bufs) != 0);
BUILD_BUG_ON(offsetof(struct io_uring_buf, resv) !=
offsetof(struct io_uring_buf_ring, tail));
/* should fit into one byte */
BUILD_BUG_ON(SQE_VALID_FLAGS >= (1 << 8));
BUILD_BUG_ON(SQE_COMMON_FLAGS >= (1 << 8));
BUILD_BUG_ON((SQE_VALID_FLAGS | SQE_COMMON_FLAGS) != SQE_VALID_FLAGS);
BUILD_BUG_ON(__REQ_F_LAST_BIT > 8 * sizeof_field(struct io_kiocb, flags));
BUILD_BUG_ON(sizeof(atomic_t) != sizeof(u32));
/* top 8bits are for internal use */
BUILD_BUG_ON((IORING_URING_CMD_MASK & 0xff000000) != 0);
io_uring_optable_init();
/* imu->dir is u8 */
BUILD_BUG_ON((IO_IMU_DEST | IO_IMU_SOURCE) > U8_MAX);
/*
* Allow user copy in the per-command field, which starts after the
* file in io_kiocb and until the opcode field. The openat2 handling
* requires copying in user memory into the io_kiocb object in that
* range, and HARDENED_USERCOPY will complain if we haven't
* correctly annotated this range.
*/
req_cachep = kmem_cache_create("io_kiocb", sizeof(struct io_kiocb), &kmem_args,
SLAB_HWCACHE_ALIGN | SLAB_PANIC | SLAB_ACCOUNT |
SLAB_TYPESAFE_BY_RCU);
iou_wq = alloc_workqueue("iou_exit", WQ_UNBOUND, 64);
BUG_ON(!iou_wq);
#ifdef CONFIG_SYSCTL
register_sysctl_init("kernel", kernel_io_uring_disabled_table);
#endif
return 0;
};
__initcall(io_uring_init);
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