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iov_iter: add iter_iovec() helper

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This returns a pointer to the current iovec entry in the iterator. Only
useful with ITER_IOVEC right now, but it prepares us to treat ITER_UBUF
and ITER_IOVEC identically for the first segment.

Rename struct iov_iter->iov to iov_iter->__iov to find any potentially
troublesome spots, and also to prevent anyone from adding new code that
accesses iter->iov directly.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Jens Axboe 2023-03-29 08:52:15 -06:00
parent 0a2481cde2
commit de4f5fed3f
12 changed files with 73 additions and 53 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

4
block/blk-map.c
View file

@ -31,8 +31,8 @@ static struct bio_map_data *bio_alloc_map_data(struct iov_iter *data,
return NULL;
bmd->iter = *data;
if (iter_is_iovec(data)) {
memcpy(bmd->iov, data->iov, sizeof(struct iovec) * data->nr_segs);
bmd->iter.iov = bmd->iov;
memcpy(bmd->iov, iter_iov(data), sizeof(struct iovec) * data->nr_segs);
bmd->iter.__iov = bmd->iov;
}
return bmd;
}

3
drivers/infiniband/hw/hfi1/file_ops.c
View file

@ -287,11 +287,12 @@ static ssize_t hfi1_write_iter(struct kiocb *kiocb, struct iov_iter *from)
}
while (dim) {
const struct iovec *iov = iter_iov(from);
int ret;
unsigned long count = 0;
ret = hfi1_user_sdma_process_request(
fd, (struct iovec *)(from->iov + done),
fd, (struct iovec *)(iov + done),
dim, &count);
if (ret) {
reqs = ret;

2
drivers/infiniband/hw/qib/qib_file_ops.c
View file

@ -2248,7 +2248,7 @@ static ssize_t qib_write_iter(struct kiocb *iocb, struct iov_iter *from)
if (!iter_is_iovec(from) || !from->nr_segs || !pq)
return -EINVAL;
return qib_user_sdma_writev(rcd, pq, from->iov, from->nr_segs);
return qib_user_sdma_writev(rcd, pq, iter_iov(from), from->nr_segs);
}
static struct class *qib_class;

3
drivers/net/tun.c
View file

@ -1486,7 +1486,8 @@ static struct sk_buff *tun_napi_alloc_frags(struct tun_file *tfile,
skb->truesize += skb->data_len;
for (i = 1; i < it->nr_segs; i++) {
size_t fragsz = it->iov[i].iov_len;
const struct iovec *iov = iter_iov(it);
size_t fragsz = iov->iov_len;
struct page *page;
void *frag;

2
drivers/vhost/scsi.c
View file

@ -671,7 +671,7 @@ vhost_scsi_calc_sgls(struct iov_iter *iter, size_t bytes, int max_sgls)
{
int sgl_count = 0;
if (!iter || !iter->iov) {
if (!iter || !iter_iov(iter)) {
pr_err("%s: iter->iov is NULL, but expected bytes: %zu"
" present\n", __func__, bytes);
return -EINVAL;

11
fs/btrfs/file.c
View file

@ -3730,10 +3730,15 @@ static int check_direct_read(struct btrfs_fs_info *fs_info,
if (!iter_is_iovec(iter))
return 0;
for (seg = 0; seg < iter->nr_segs; seg++)
for (i = seg + 1; i < iter->nr_segs; i++)
if (iter->iov[seg].iov_base == iter->iov[i].iov_base)
for (seg = 0; seg < iter->nr_segs; seg++) {
for (i = seg + 1; i < iter->nr_segs; i++) {
const struct iovec *iov1 = iter_iov(iter) + seg;
const struct iovec *iov2 = iter_iov(iter) + i;
if (iov1->iov_base == iov2->iov_base)
return -EINVAL;
}
}
return 0;
}

2
fs/fuse/file.c
View file

@ -1419,7 +1419,7 @@ static ssize_t fuse_cache_write_iter(struct kiocb *iocb, struct iov_iter *from)
static inline unsigned long fuse_get_user_addr(const struct iov_iter *ii)
{
return (unsigned long)ii->iov->iov_base + ii->iov_offset;
return (unsigned long)iter_iov(ii)->iov_base + ii->iov_offset;
}
static inline size_t fuse_get_frag_size(const struct iov_iter *ii,

9
include/linux/uio.h
View file

@ -51,7 +51,8 @@ struct iov_iter {
};
size_t count;
union {
const struct iovec *iov;
/* use iter_iov() to get the current vec */
const struct iovec *__iov;
const struct kvec *kvec;
const struct bio_vec *bvec;
struct xarray *xarray;
@ -68,6 +69,8 @@ struct iov_iter {
};
};
#define iter_iov(iter) (iter)->__iov
static inline enum iter_type iov_iter_type(const struct iov_iter *i)
{
return i->iter_type;
@ -146,9 +149,9 @@ static inline size_t iov_length(const struct iovec *iov, unsigned long nr_segs)
static inline struct iovec iov_iter_iovec(const struct iov_iter *iter)
{
return (struct iovec) {
.iov_base = iter->iov->iov_base + iter->iov_offset,
.iov_base = iter_iov(iter)->iov_base + iter->iov_offset,
.iov_len = min(iter->count,
iter->iov->iov_len - iter->iov_offset),
iter_iov(iter)->iov_len - iter->iov_offset),
};
}

4
io_uring/net.c
View file

@ -184,8 +184,8 @@ static int io_setup_async_msg(struct io_kiocb *req,
async_msg->msg.msg_name = &async_msg->addr;
/* if were using fast_iov, set it to the new one */
if (iter_is_iovec(&kmsg->msg.msg_iter) && !kmsg->free_iov) {
size_t fast_idx = kmsg->msg.msg_iter.iov - kmsg->fast_iov;
async_msg->msg.msg_iter.iov = &async_msg->fast_iov[fast_idx];
size_t fast_idx = iter_iov(&kmsg->msg.msg_iter) - kmsg->fast_iov;
async_msg->msg.msg_iter.__iov = &async_msg->fast_iov[fast_idx];
}
return -EAGAIN;

8
io_uring/rw.c
View file

@ -503,10 +503,10 @@ static void io_req_map_rw(struct io_kiocb *req, const struct iovec *iovec,
if (!iovec) {
unsigned iov_off = 0;
io->s.iter.iov = io->s.fast_iov;
if (iter->iov != fast_iov) {
iov_off = iter->iov - fast_iov;
io->s.iter.iov += iov_off;
io->s.iter.__iov = io->s.fast_iov;
if (iter->__iov != fast_iov) {
iov_off = iter_iov(iter) - fast_iov;
io->s.iter.__iov += iov_off;
}
if (io->s.fast_iov != fast_iov)
memcpy(io->s.fast_iov + iov_off, fast_iov + iov_off,

56
lib/iov_iter.c
View file

@ -126,13 +126,13 @@ __out: \
iterate_buf(i, n, base, len, off, \
i->ubuf, (I)) \
} else if (likely(iter_is_iovec(i))) { \
const struct iovec *iov = i->iov; \
const struct iovec *iov = iter_iov(i); \
void __user *base; \
size_t len; \
iterate_iovec(i, n, base, len, off, \
iov, (I)) \
i->nr_segs -= iov - i->iov; \
i->iov = iov; \
i->nr_segs -= iov - iter_iov(i); \
i->__iov = iov; \
} else if (iov_iter_is_bvec(i)) { \
const struct bio_vec *bvec = i->bvec; \
void *base; \
@ -355,7 +355,7 @@ size_t fault_in_iov_iter_readable(const struct iov_iter *i, size_t size)
size_t skip;
size -= count;
for (p = i->iov, skip = i->iov_offset; count; p++, skip = 0) {
for (p = iter_iov(i), skip = i->iov_offset; count; p++, skip = 0) {
size_t len = min(count, p->iov_len - skip);
size_t ret;
@ -398,7 +398,7 @@ size_t fault_in_iov_iter_writeable(const struct iov_iter *i, size_t size)
size_t skip;
size -= count;
for (p = i->iov, skip = i->iov_offset; count; p++, skip = 0) {
for (p = iter_iov(i), skip = i->iov_offset; count; p++, skip = 0) {
size_t len = min(count, p->iov_len - skip);
size_t ret;
@ -425,7 +425,7 @@ void iov_iter_init(struct iov_iter *i, unsigned int direction,
.nofault = false,
.user_backed = true,
.data_source = direction,
.iov = iov,
.__iov = iov,
.nr_segs = nr_segs,
.iov_offset = 0,
.count = count
@ -876,14 +876,14 @@ static void iov_iter_iovec_advance(struct iov_iter *i, size_t size)
i->count -= size;
size += i->iov_offset; // from beginning of current segment
for (iov = i->iov, end = iov + i->nr_segs; iov < end; iov++) {
for (iov = iter_iov(i), end = iov + i->nr_segs; iov < end; iov++) {
if (likely(size < iov->iov_len))
break;
size -= iov->iov_len;
}
i->iov_offset = size;
i->nr_segs -= iov - i->iov;
i->iov = iov;
i->nr_segs -= iov - iter_iov(i);
i->__iov = iov;
}
void iov_iter_advance(struct iov_iter *i, size_t size)
@ -958,12 +958,12 @@ void iov_iter_revert(struct iov_iter *i, size_t unroll)
unroll -= n;
}
} else { /* same logics for iovec and kvec */
const struct iovec *iov = i->iov;
const struct iovec *iov = iter_iov(i);
while (1) {
size_t n = (--iov)->iov_len;
i->nr_segs++;
if (unroll <= n) {
i->iov = iov;
i->__iov = iov;
i->iov_offset = n - unroll;
return;
}
@ -980,7 +980,7 @@ size_t iov_iter_single_seg_count(const struct iov_iter *i)
{
if (i->nr_segs > 1) {
if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i)))
return min(i->count, i->iov->iov_len - i->iov_offset);
return min(i->count, iter_iov(i)->iov_len - i->iov_offset);
if (iov_iter_is_bvec(i))
return min(i->count, i->bvec->bv_len - i->iov_offset);
}
@ -1095,13 +1095,14 @@ static bool iov_iter_aligned_iovec(const struct iov_iter *i, unsigned addr_mask,
unsigned k;
for (k = 0; k < i->nr_segs; k++, skip = 0) {
size_t len = i->iov[k].iov_len - skip;
const struct iovec *iov = iter_iov(i) + k;
size_t len = iov->iov_len - skip;
if (len > size)
len = size;
if (len & len_mask)
return false;
if ((unsigned long)(i->iov[k].iov_base + skip) & addr_mask)
if ((unsigned long)(iov->iov_base + skip) & addr_mask)
return false;
size -= len;
@ -1194,9 +1195,10 @@ static unsigned long iov_iter_alignment_iovec(const struct iov_iter *i)
unsigned k;
for (k = 0; k < i->nr_segs; k++, skip = 0) {
size_t len = i->iov[k].iov_len - skip;
const struct iovec *iov = iter_iov(i) + k;
size_t len = iov->iov_len - skip;
if (len) {
res |= (unsigned long)i->iov[k].iov_base + skip;
res |= (unsigned long)iov->iov_base + skip;
if (len > size)
len = size;
res |= len;
@ -1273,14 +1275,15 @@ unsigned long iov_iter_gap_alignment(const struct iov_iter *i)
return ~0U;
for (k = 0; k < i->nr_segs; k++) {
if (i->iov[k].iov_len) {
unsigned long base = (unsigned long)i->iov[k].iov_base;
const struct iovec *iov = iter_iov(i) + k;
if (iov->iov_len) {
unsigned long base = (unsigned long)iov->iov_base;
if (v) // if not the first one
res |= base | v; // this start | previous end
v = base + i->iov[k].iov_len;
if (size <= i->iov[k].iov_len)
v = base + iov->iov_len;
if (size <= iov->iov_len)
break;
size -= i->iov[k].iov_len;
size -= iov->iov_len;
}
}
return res;
@ -1396,13 +1399,14 @@ static unsigned long first_iovec_segment(const struct iov_iter *i, size_t *size)
return (unsigned long)i->ubuf + i->iov_offset;
for (k = 0, skip = i->iov_offset; k < i->nr_segs; k++, skip = 0) {
size_t len = i->iov[k].iov_len - skip;
const struct iovec *iov = iter_iov(i) + k;
size_t len = iov->iov_len - skip;
if (unlikely(!len))
continue;
if (*size > len)
*size = len;
return (unsigned long)i->iov[k].iov_base + skip;
return (unsigned long)iov->iov_base + skip;
}
BUG(); // if it had been empty, we wouldn't get called
}
@ -1614,7 +1618,7 @@ static int iov_npages(const struct iov_iter *i, int maxpages)
const struct iovec *p;
int npages = 0;
for (p = i->iov; size; skip = 0, p++) {
for (p = iter_iov(i); size; skip = 0, p++) {
unsigned offs = offset_in_page(p->iov_base + skip);
size_t len = min(p->iov_len - skip, size);
@ -1691,7 +1695,7 @@ const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags)
flags);
else if (iov_iter_is_kvec(new) || iter_is_iovec(new))
/* iovec and kvec have identical layout */
return new->iov = kmemdup(new->iov,
return new->__iov = kmemdup(new->__iov,
new->nr_segs * sizeof(struct iovec),
flags);
return NULL;
@ -1918,7 +1922,7 @@ void iov_iter_restore(struct iov_iter *i, struct iov_iter_state *state)
if (iov_iter_is_bvec(i))
i->bvec -= state->nr_segs - i->nr_segs;
else
i->iov -= state->nr_segs - i->nr_segs;
i->__iov -= state->nr_segs - i->nr_segs;
i->nr_segs = state->nr_segs;
}

22
sound/core/pcm_native.c
View file

@ -3521,6 +3521,7 @@ static ssize_t snd_pcm_readv(struct kiocb *iocb, struct iov_iter *to)
unsigned long i;
void __user **bufs;
snd_pcm_uframes_t frames;
const struct iovec *iov = iter_iov(to);
pcm_file = iocb->ki_filp->private_data;
substream = pcm_file->substream;
@ -3534,14 +3535,16 @@ static ssize_t snd_pcm_readv(struct kiocb *iocb, struct iov_iter *to)
return -EINVAL;
if (to->nr_segs > 1024 || to->nr_segs != runtime->channels)
return -EINVAL;
if (!frame_aligned(runtime, to->iov->iov_len))
if (!frame_aligned(runtime, iov->iov_len))
return -EINVAL;
frames = bytes_to_samples(runtime, to->iov->iov_len);
frames = bytes_to_samples(runtime, iov->iov_len);
bufs = kmalloc_array(to->nr_segs, sizeof(void *), GFP_KERNEL);
if (bufs == NULL)
return -ENOMEM;
for (i = 0; i < to->nr_segs; ++i)
bufs[i] = to->iov[i].iov_base;
for (i = 0; i < to->nr_segs; ++i) {
bufs[i] = iov->iov_base;
iov++;
}
result = snd_pcm_lib_readv(substream, bufs, frames);
if (result > 0)
result = frames_to_bytes(runtime, result);
@ -3558,6 +3561,7 @@ static ssize_t snd_pcm_writev(struct kiocb *iocb, struct iov_iter *from)
unsigned long i;
void __user **bufs;
snd_pcm_uframes_t frames;
const struct iovec *iov = iter_iov(from);
pcm_file = iocb->ki_filp->private_data;
substream = pcm_file->substream;
@ -3570,14 +3574,16 @@ static ssize_t snd_pcm_writev(struct kiocb *iocb, struct iov_iter *from)
if (!iter_is_iovec(from))
return -EINVAL;
if (from->nr_segs > 128 || from->nr_segs != runtime->channels ||
!frame_aligned(runtime, from->iov->iov_len))
!frame_aligned(runtime, iov->iov_len))
return -EINVAL;
frames = bytes_to_samples(runtime, from->iov->iov_len);
frames = bytes_to_samples(runtime, iov->iov_len);
bufs = kmalloc_array(from->nr_segs, sizeof(void *), GFP_KERNEL);
if (bufs == NULL)
return -ENOMEM;
for (i = 0; i < from->nr_segs; ++i)
bufs[i] = from->iov[i].iov_base;
for (i = 0; i < from->nr_segs; ++i) {
bufs[i] = iov->iov_base;
iov++;
}
result = snd_pcm_lib_writev(substream, bufs, frames);
if (result > 0)
result = frames_to_bytes(runtime, result);