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vhost/scsi: Add ANY_LAYOUT support in vhost_scsi_handle_vq

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This patch adds ANY_LAYOUT compatible support within the existing
vhost_scsi_handle_vq() ->handle_kick() callback.

It calculates data_direction + exp_data_len for the new tcm_vhost_cmd
descriptor by walking both outgoing + incoming iovecs using iov_iter,
assuming the layout of outgoing request header + T10_PI + Data payload
comes first.

It also uses copy_from_iter() to copy leading virtio-scsi request header
that may or may not include SCSI CDB, that returns a re-calculated iovec
to start of T10_PI or Data SGL memory.

Also, go ahead and drop the legacy pre virtio v1.0 !ANY_LAYOUT logic.

Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
This commit is contained in:
Nicholas Bellinger 2015-01-25 21:14:58 -08:00
parent e8de56b5e7
commit 09b13fa8c1
1 changed files with 110 additions and 196 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

296
drivers/vhost/scsi.c
View file

@ -827,93 +827,6 @@ vhost_scsi_map_to_sgl(struct tcm_vhost_cmd *cmd,
return ret;
}
static int
vhost_scsi_map_iov_to_sgl(struct tcm_vhost_cmd *cmd,
struct iovec *iov,
int niov,
bool write)
{
struct scatterlist *sg = cmd->tvc_sgl;
unsigned int sgl_count = 0;
int ret, i;
for (i = 0; i < niov; i++)
sgl_count += iov_num_pages(iov[i].iov_base, iov[i].iov_len);
if (sgl_count > TCM_VHOST_PREALLOC_SGLS) {
pr_err("vhost_scsi_map_iov_to_sgl() sgl_count: %u greater than"
" preallocated TCM_VHOST_PREALLOC_SGLS: %u\n",
sgl_count, TCM_VHOST_PREALLOC_SGLS);
return -ENOBUFS;
}
pr_debug("%s sg %p sgl_count %u\n", __func__, sg, sgl_count);
sg_init_table(sg, sgl_count);
cmd->tvc_sgl_count = sgl_count;
pr_debug("Mapping iovec %p for %u pages\n", &iov[0], sgl_count);
for (i = 0; i < niov; i++) {
ret = vhost_scsi_map_to_sgl(cmd, iov[i].iov_base, iov[i].iov_len,
sg, write);
if (ret < 0) {
for (i = 0; i < cmd->tvc_sgl_count; i++) {
struct page *page = sg_page(&cmd->tvc_sgl[i]);
if (page)
put_page(page);
}
cmd->tvc_sgl_count = 0;
return ret;
}
sg += ret;
sgl_count -= ret;
}
return 0;
}
static int
vhost_scsi_map_iov_to_prot(struct tcm_vhost_cmd *cmd,
struct iovec *iov,
int niov,
bool write)
{
struct scatterlist *prot_sg = cmd->tvc_prot_sgl;
unsigned int prot_sgl_count = 0;
int ret, i;
for (i = 0; i < niov; i++)
prot_sgl_count += iov_num_pages(iov[i].iov_base, iov[i].iov_len);
if (prot_sgl_count > TCM_VHOST_PREALLOC_PROT_SGLS) {
pr_err("vhost_scsi_map_iov_to_prot() sgl_count: %u greater than"
" preallocated TCM_VHOST_PREALLOC_PROT_SGLS: %u\n",
prot_sgl_count, TCM_VHOST_PREALLOC_PROT_SGLS);
return -ENOBUFS;
}
pr_debug("%s prot_sg %p prot_sgl_count %u\n", __func__,
prot_sg, prot_sgl_count);
sg_init_table(prot_sg, prot_sgl_count);
cmd->tvc_prot_sgl_count = prot_sgl_count;
for (i = 0; i < niov; i++) {
ret = vhost_scsi_map_to_sgl(cmd, iov[i].iov_base, iov[i].iov_len,
prot_sg, write);
if (ret < 0) {
for (i = 0; i < cmd->tvc_prot_sgl_count; i++) {
struct page *page = sg_page(&cmd->tvc_prot_sgl[i]);
if (page)
put_page(page);
}
cmd->tvc_prot_sgl_count = 0;
return ret;
}
prot_sg += ret;
prot_sgl_count -= ret;
}
return 0;
}
static int
vhost_scsi_calc_sgls(struct iov_iter *iter, size_t bytes, int max_sgls)
{
@ -1064,19 +977,20 @@ vhost_scsi_send_bad_target(struct vhost_scsi *vs,
static void
vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
{
struct tcm_vhost_tpg **vs_tpg;
struct tcm_vhost_tpg **vs_tpg, *tpg;
struct virtio_scsi_cmd_req v_req;
struct virtio_scsi_cmd_req_pi v_req_pi;
struct tcm_vhost_tpg *tpg;
struct tcm_vhost_cmd *cmd;
struct iov_iter out_iter, in_iter, prot_iter, data_iter;
u64 tag;
u32 exp_data_len, data_first, data_num, data_direction, prot_first;
unsigned out, in, i;
int head, ret, data_niov, prot_niov, prot_bytes;
size_t req_size;
u32 exp_data_len, data_direction;
unsigned out, in;
int head, ret, prot_bytes;
size_t req_size, rsp_size = sizeof(struct virtio_scsi_cmd_resp);
size_t out_size, in_size;
u16 lun;
u8 *target, *lunp, task_attr;
bool hdr_pi;
bool t10_pi = vhost_has_feature(vq, VIRTIO_SCSI_F_T10_PI);
void *req, *cdb;
mutex_lock(&vq->mutex);
@ -1107,117 +1021,134 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
}
break;
}
/* FIXME: BIDI operation */
if (out == 1 && in == 1) {
data_direction = DMA_NONE;
data_first = 0;
data_num = 0;
} else if (out == 1 && in > 1) {
data_direction = DMA_FROM_DEVICE;
data_first = out + 1;
data_num = in - 1;
} else if (out > 1 && in == 1) {
data_direction = DMA_TO_DEVICE;
data_first = 1;
data_num = out - 1;
} else {
vq_err(vq, "Invalid buffer layout out: %u in: %u\n",
out, in);
break;
}
/*
* Check for a sane resp buffer so we can report errors to
* the guest.
* Check for a sane response buffer so we can report early
* errors back to the guest.
*/
if (unlikely(vq->iov[out].iov_len !=
sizeof(struct virtio_scsi_cmd_resp))) {
vq_err(vq, "Expecting virtio_scsi_cmd_resp, got %zu"
" bytes\n", vq->iov[out].iov_len);
if (unlikely(vq->iov[out].iov_len < rsp_size)) {
vq_err(vq, "Expecting at least virtio_scsi_cmd_resp"
" size, got %zu bytes\n", vq->iov[out].iov_len);
break;
}
if (vhost_has_feature(vq, VIRTIO_SCSI_F_T10_PI)) {
/*
* Setup pointers and values based upon different virtio-scsi
* request header if T10_PI is enabled in KVM guest.
*/
if (t10_pi) {
req = &v_req_pi;
req_size = sizeof(v_req_pi);
lunp = &v_req_pi.lun[0];
target = &v_req_pi.lun[1];
req_size = sizeof(v_req_pi);
hdr_pi = true;
} else {
req = &v_req;
req_size = sizeof(v_req);
lunp = &v_req.lun[0];
target = &v_req.lun[1];
req_size = sizeof(v_req);
hdr_pi = false;
}
/*
* FIXME: Not correct for BIDI operation
*/
out_size = iov_length(vq->iov, out);
in_size = iov_length(&vq->iov[out], in);
if (unlikely(vq->iov[0].iov_len < req_size)) {
pr_err("Expecting virtio-scsi header: %zu, got %zu\n",
req_size, vq->iov[0].iov_len);
/*
* Copy over the virtio-scsi request header, which for a
* ANY_LAYOUT enabled guest may span multiple iovecs, or a
* single iovec may contain both the header + outgoing
* WRITE payloads.
*
* copy_from_iter() will advance out_iter, so that it will
* point at the start of the outgoing WRITE payload, if
* DMA_TO_DEVICE is set.
*/
iov_iter_init(&out_iter, WRITE, vq->iov, out, out_size);
ret = copy_from_iter(req, req_size, &out_iter);
if (unlikely(ret != req_size)) {
vq_err(vq, "Faulted on copy_from_iter\n");
vhost_scsi_send_bad_target(vs, vq, head, out);
continue;
}
ret = memcpy_fromiovecend(req, &vq->iov[0], 0, req_size);
if (unlikely(ret)) {
vq_err(vq, "Faulted on virtio_scsi_cmd_req\n");
vhost_scsi_send_bad_target(vs, vq, head, out);
continue;
}
/* virtio-scsi spec requires byte 0 of the lun to be 1 */
if (unlikely(*lunp != 1)) {
vq_err(vq, "Illegal virtio-scsi lun: %u\n", *lunp);
vhost_scsi_send_bad_target(vs, vq, head, out);
continue;
}
tpg = ACCESS_ONCE(vs_tpg[*target]);
/* Target does not exist, fail the request */
if (unlikely(!tpg)) {
/* Target does not exist, fail the request */
vhost_scsi_send_bad_target(vs, vq, head, out);
continue;
}
data_niov = data_num;
prot_niov = prot_first = prot_bytes = 0;
/*
* Determine if any protection information iovecs are preceeding
* the actual data payload, and adjust data_first + data_niov
* values accordingly for vhost_scsi_map_iov_to_sgl() below.
* Determine data_direction by calculating the total outgoing
* iovec sizes + incoming iovec sizes vs. virtio-scsi request +
* response headers respectively.
*
* Also extract virtio_scsi header bits for vhost_scsi_get_tag()
* For DMA_TO_DEVICE this is out_iter, which is already pointing
* to the right place.
*
* For DMA_FROM_DEVICE, the iovec will be just past the end
* of the virtio-scsi response header in either the same
* or immediately following iovec.
*
* Any associated T10_PI bytes for the outgoing / incoming
* payloads are included in calculation of exp_data_len here.
*/
if (hdr_pi) {
prot_bytes = 0;
if (out_size > req_size) {
data_direction = DMA_TO_DEVICE;
exp_data_len = out_size - req_size;
data_iter = out_iter;
} else if (in_size > rsp_size) {
data_direction = DMA_FROM_DEVICE;
exp_data_len = in_size - rsp_size;
iov_iter_init(&in_iter, READ, &vq->iov[out], in,
rsp_size + exp_data_len);
iov_iter_advance(&in_iter, rsp_size);
data_iter = in_iter;
} else {
data_direction = DMA_NONE;
exp_data_len = 0;
}
/*
* If T10_PI header + payload is present, setup prot_iter values
* and recalculate data_iter for vhost_scsi_mapal() mapping to
* host scatterlists via get_user_pages_fast().
*/
if (t10_pi) {
if (v_req_pi.pi_bytesout) {
if (data_direction != DMA_TO_DEVICE) {
vq_err(vq, "Received non zero do_pi_niov"
", but wrong data_direction\n");
vq_err(vq, "Received non zero pi_bytesout,"
" but wrong data_direction\n");
vhost_scsi_send_bad_target(vs, vq, head, out);
continue;
}
prot_bytes = vhost32_to_cpu(vq, v_req_pi.pi_bytesout);
} else if (v_req_pi.pi_bytesin) {
if (data_direction != DMA_FROM_DEVICE) {
vq_err(vq, "Received non zero di_pi_niov"
", but wrong data_direction\n");
vq_err(vq, "Received non zero pi_bytesin,"
" but wrong data_direction\n");
vhost_scsi_send_bad_target(vs, vq, head, out);
continue;
}
prot_bytes = vhost32_to_cpu(vq, v_req_pi.pi_bytesin);
}
/*
* Set prot_iter to data_iter, and advance past any
* preceeding prot_bytes that may be present.
*
* Also fix up the exp_data_len to reflect only the
* actual data payload length.
*/
if (prot_bytes) {
int tmp = 0;
for (i = 0; i < data_num; i++) {
tmp += vq->iov[data_first + i].iov_len;
prot_niov++;
if (tmp >= prot_bytes)
break;
}
prot_first = data_first;
data_first += prot_niov;
data_niov = data_num - prot_niov;
exp_data_len -= prot_bytes;
prot_iter = data_iter;
iov_iter_advance(&data_iter, prot_bytes);
}
tag = vhost64_to_cpu(vq, v_req_pi.tag);
task_attr = v_req_pi.task_attr;
@ -1229,12 +1160,10 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
cdb = &v_req.cdb[0];
lun = ((v_req.lun[2] << 8) | v_req.lun[3]) & 0x3FFF;
}
exp_data_len = 0;
for (i = 0; i < data_niov; i++)
exp_data_len += vq->iov[data_first + i].iov_len;
/*
* Check that the recieved CDB size does not exceeded our
* hardcoded max for vhost-scsi
* Check that the received CDB size does not exceeded our
* hardcoded max for vhost-scsi, then get a pre-allocated
* cmd descriptor for the new virtio-scsi tag.
*
* TODO what if cdb was too small for varlen cdb header?
*/
@ -1245,7 +1174,6 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
vhost_scsi_send_bad_target(vs, vq, head, out);
continue;
}
cmd = vhost_scsi_get_tag(vq, tpg, cdb, tag, lun, task_attr,
exp_data_len + prot_bytes,
data_direction);
@ -1255,10 +1183,6 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
vhost_scsi_send_bad_target(vs, vq, head, out);
continue;
}
pr_debug("Allocated tv_cmd: %p exp_data_len: %d, data_direction"
": %d\n", cmd, exp_data_len, data_direction);
cmd->tvc_vhost = vs;
cmd->tvc_vq = vq;
cmd->tvc_resp_iov = &vq->iov[out];
@ -1266,23 +1190,13 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
pr_debug("vhost_scsi got command opcode: %#02x, lun: %d\n",
cmd->tvc_cdb[0], cmd->tvc_lun);
pr_debug("cmd: %p exp_data_len: %d, prot_bytes: %d data_direction:"
" %d\n", cmd, exp_data_len, prot_bytes, data_direction);
if (prot_niov) {
ret = vhost_scsi_map_iov_to_prot(cmd,
&vq->iov[prot_first], prot_niov,
data_direction == DMA_FROM_DEVICE);
if (unlikely(ret)) {
vq_err(vq, "Failed to map iov to"
" prot_sgl\n");
tcm_vhost_release_cmd(&cmd->tvc_se_cmd);
vhost_scsi_send_bad_target(vs, vq, head, out);
continue;
}
}
if (data_direction != DMA_NONE) {
ret = vhost_scsi_map_iov_to_sgl(cmd,
&vq->iov[data_first], data_niov,
data_direction == DMA_FROM_DEVICE);
ret = vhost_scsi_mapal(cmd,
prot_bytes, &prot_iter,
exp_data_len, &data_iter);
if (unlikely(ret)) {
vq_err(vq, "Failed to map iov to sgl\n");
tcm_vhost_release_cmd(&cmd->tvc_se_cmd);
@ -1293,14 +1207,14 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
/*
* Save the descriptor from vhost_get_vq_desc() to be used to
* complete the virtio-scsi request in TCM callback context via
* tcm_vhost_queue_data_in() and tcm_vhost_queue_status()
* vhost_scsi_queue_data_in() and vhost_scsi_queue_status()
*/
cmd->tvc_vq_desc = head;
/*
* Dispatch tv_cmd descriptor for cmwq execution in process
* context provided by tcm_vhost_workqueue. This also ensures
* tv_cmd is executed on the same kworker CPU as this vhost
* thread to gain positive L2 cache locality effects..
* Dispatch cmd descriptor for cmwq execution in process
* context provided by vhost_scsi_workqueue. This also ensures
* cmd is executed on the same kworker CPU as this vhost
* thread to gain positive L2 cache locality effects.
*/
INIT_WORK(&cmd->work, tcm_vhost_submission_work);
queue_work(tcm_vhost_workqueue, &cmd->work);