[RFC 4/6] vhost/scsi: Enable T10 PI IOV -> SGL memory mapping

Nicholas A. Bellinger
2014-02-24T05:32:28Z

This patch updates vhost_scsi_handle_vq() to calculate a data_niov +
prot_niov currently based upon virtio_scsi_cmd_req->prio for figuring
out many of seperate data + protection SGLs to expect from data_num.

Also update tcm_vhost_submission_work() to pass the pre-allocated
cmd->tvc_prot_sgl[] memory into target_submit_cmd_map_sgls().

Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Sagi Grimberg <sagig@dev.mellanox.co.il>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
---
drivers/vhost/scsi.c | 45 ++++++++++++++++++++++++++++++---------------
1 file changed, 30 insertions(+), 15 deletions(-)

diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
index 0cf5948..3bdb625 100644
--- a/drivers/vhost/scsi.c
+++ b/drivers/vhost/scsi.c
@@ -908,18 +908,15 @@ static void tcm_vhost_submission_work(struct work_struct *work)
container_of(work, struct tcm_vhost_cmd, work);
struct tcm_vhost_nexus *tv_nexus;
struct se_cmd *se_cmd = &cmd->tvc_se_cmd;
- struct scatterlist *sg_ptr, *sg_bidi_ptr = NULL;
- int rc, sg_no_bidi = 0;
+ struct scatterlist *sg_ptr, *sg_prot_ptr = NULL;
+ int rc;

+ /* FIXME: BIDI operation */
if (cmd->tvc_sgl_count) {
sg_ptr = cmd->tvc_sgl;
-/* FIXME: Fix BIDI operation in tcm_vhost_submission_work() */
-#if 0
- if (se_cmd->se_cmd_flags & SCF_BIDI) {
- sg_bidi_ptr = NULL;
- sg_no_bidi = 0;
- }
-#endif
+
+ if (cmd->tvc_prot_sgl_count)
+ sg_prot_ptr = cmd->tvc_prot_sgl;
} else {
sg_ptr = NULL;
}
@@ -930,7 +927,7 @@ static void tcm_vhost_submission_work(struct work_struct *work)
cmd->tvc_lun, cmd->tvc_exp_data_len,
cmd->tvc_task_attr, cmd->tvc_data_direction,
TARGET_SCF_ACK_KREF, sg_ptr, cmd->tvc_sgl_count,
- sg_bidi_ptr, sg_no_bidi, NULL, 0);
+ NULL, 0, sg_prot_ptr, cmd->tvc_prot_sgl_count);
if (rc < 0) {
transport_send_check_condition_and_sense(se_cmd,
TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE, 0);
@@ -966,7 +963,7 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
struct tcm_vhost_cmd *cmd;
u32 exp_data_len, data_first, data_num, data_direction;
unsigned out, in, i;
- int head, ret;
+ int head, ret, data_niov, prot_niov;
u8 target;

mutex_lock(&vq->mutex);
@@ -998,7 +995,7 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
break;
}

-/* FIXME: BIDI operation */
+ /* FIXME: BIDI operation */
if (out == 1 && in == 1) {
data_direction = DMA_NONE;
data_first = 0;
@@ -1052,8 +1049,17 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)
continue;
}

+ data_niov = data_num;
+ prot_niov = 0;
+
+ if (data_num && v_req.prio != 0) {
+ /* FIXME: Figure out a better way.. */
+ data_niov = data_num - v_req.prio;
+ prot_niov = v_req.prio;
+ }
+
exp_data_len = 0;
- for (i = 0; i < data_num; i++)
+ for (i = 0; i < data_niov; i++)
exp_data_len += vq->iov[data_first + i].iov_len;

cmd = vhost_scsi_get_tag(vq, tpg, &v_req,
@@ -1096,14 +1102,23 @@ vhost_scsi_handle_vq(struct vhost_scsi *vs, struct vhost_virtqueue *vq)

if (data_direction != DMA_NONE) {
ret = vhost_scsi_map_iov_to_sgl(cmd,
- &vq->iov[data_first], data_num,
+ &vq->iov[data_first], data_niov,
data_direction == DMA_FROM_DEVICE);
if (unlikely(ret)) {
vq_err(vq, "Failed to map iov to sgl\n");
goto err_free;
}
}
-
+ if (prot_niov) {
+ ret = vhost_scsi_map_iov_to_prot(cmd,
+ &vq->iov[data_first + data_niov], prot_niov,
+ data_direction == DMA_FROM_DEVICE);
+ if (unlikely(ret)) {
+ vq_err(vq, "Failed to map iov to"
+ " prot_sgl\n");
+ goto err_free;
+ }
+ }
/*
* Save the descriptor from vhost_get_vq_desc() to be used to
* complete the virtio-scsi request in TCM callback context via
--
1.7.10.4