tcm_vhost: Convert I/O path to use target_submit_cmd_map_sgls

This patch converts tcm_vhost to use target_submit_cmd_map_sgls() for
I/O submission and mapping of pre-allocated SGL memory from incoming
virtio-scsi SGL memory -> se_cmd descriptors.

This includes removing the original open-coded fabric uses of target
core callers to support transport_generic_map_mem_to_cmd() between
target_setup_cmd_from_cdb() and transport_handle_cdb_direct() logic.

It also includes adding a handful of new tcm_vhost_cmnd member +
assignments in vhost_scsi_allocate_cmd() used from cmwq process
context I/O submission within tcm_vhost_submission_work()

(v2: Use renamed target_submit_cmd_map_sgls)

Reported-by: Christoph Hellwig <hch@lst.de>
Cc: Christoph Hellwig <hch@lst.de>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Stefan Hajnoczi <stefanha@gmail.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

diff --git a/drivers/vhost/tcm_vhost.c b/drivers/vhost/tcm_vhost.c
index 89dc99b..aa31692 100644 (file)
--- a/drivers/vhost/tcm_vhost.c
+++ b/drivers/vhost/tcm_vhost.c
@@ -415,10 +415,7 @@ static struct tcm_vhost_cmd *vhost_scsi_allocate_cmd(
 {
        struct tcm_vhost_cmd *tv_cmd;
        struct tcm_vhost_nexus *tv_nexus;
-       struct se_portal_group *se_tpg = &tv_tpg->se_tpg;
        struct se_session *se_sess;
-       struct se_cmd *se_cmd;
-       int sam_task_attr;
 
        tv_nexus = tv_tpg->tpg_nexus;
        if (!tv_nexus) {
@@ -434,23 +431,11 @@ static struct tcm_vhost_cmd *vhost_scsi_allocate_cmd(
        }
        INIT_LIST_HEAD(&tv_cmd->tvc_completion_list);
        tv_cmd->tvc_tag = v_req->tag;
+       tv_cmd->tvc_task_attr = v_req->task_attr;
+       tv_cmd->tvc_exp_data_len = exp_data_len;
+       tv_cmd->tvc_data_direction = data_direction;
+       tv_cmd->tvc_nexus = tv_nexus;
 
-       se_cmd = &tv_cmd->tvc_se_cmd;
-       /*
-        * Locate the SAM Task Attr from virtio_scsi_cmd_req
-        */
-       sam_task_attr = v_req->task_attr;
-       /*
-        * Initialize struct se_cmd descriptor from TCM infrastructure
-        */
-       transport_init_se_cmd(se_cmd, se_tpg->se_tpg_tfo, se_sess, exp_data_len,
-                               data_direction, sam_task_attr,
-                               &tv_cmd->tvc_sense_buf[0]);
-
-#if 0  /* FIXME: vhost_scsi_allocate_cmd() BIDI operation */
-       if (bidi)
-               se_cmd->se_cmd_flags |= SCF_BIDI;
-#endif
        return tv_cmd;
 }
 
@@ -549,37 +534,10 @@ static void tcm_vhost_submission_work(struct work_struct *work)
 {
        struct tcm_vhost_cmd *tv_cmd =
                container_of(work, struct tcm_vhost_cmd, work);
+       struct tcm_vhost_nexus *tv_nexus;
        struct se_cmd *se_cmd = &tv_cmd->tvc_se_cmd;
        struct scatterlist *sg_ptr, *sg_bidi_ptr = NULL;
        int rc, sg_no_bidi = 0;
-       /*
-        * Locate the struct se_lun pointer based on v_req->lun, and
-        * attach it to struct se_cmd
-        */
-       rc = transport_lookup_cmd_lun(&tv_cmd->tvc_se_cmd, tv_cmd->tvc_lun);
-       if (rc < 0) {
-               pr_err("Failed to look up lun: %d\n", tv_cmd->tvc_lun);
-               transport_send_check_condition_and_sense(&tv_cmd->tvc_se_cmd,
-                       tv_cmd->tvc_se_cmd.scsi_sense_reason, 0);
-               transport_generic_free_cmd(se_cmd, 0);
-               return;
-       }
-
-       rc = target_setup_cmd_from_cdb(se_cmd, tv_cmd->tvc_cdb);
-       if (rc == -ENOMEM) {
-               transport_send_check_condition_and_sense(se_cmd,
-                               TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE, 0);
-               transport_generic_free_cmd(se_cmd, 0);
-               return;
-       } else if (rc < 0) {
-               if (se_cmd->se_cmd_flags & SCF_SCSI_RESERVATION_CONFLICT)
-                       tcm_vhost_queue_status(se_cmd);
-               else
-                       transport_send_check_condition_and_sense(se_cmd,
-                                       se_cmd->scsi_sense_reason, 0);
-               transport_generic_free_cmd(se_cmd, 0);
-               return;
-       }
 
        if (tv_cmd->tvc_sgl_count) {
                sg_ptr = tv_cmd->tvc_sgl;
@@ -597,17 +555,19 @@ static void tcm_vhost_submission_work(struct work_struct *work)
        } else {
                sg_ptr = NULL;
        }
-
-       rc = transport_generic_map_mem_to_cmd(se_cmd, sg_ptr,
-                               tv_cmd->tvc_sgl_count, sg_bidi_ptr,
-                               sg_no_bidi);
+       tv_nexus = tv_cmd->tvc_nexus;
+
+       rc = target_submit_cmd_map_sgls(se_cmd, tv_nexus->tvn_se_sess,
+                       tv_cmd->tvc_cdb, &tv_cmd->tvc_sense_buf[0],
+                       tv_cmd->tvc_lun, tv_cmd->tvc_exp_data_len,
+                       tv_cmd->tvc_task_attr, tv_cmd->tvc_data_direction,
+                       0, sg_ptr, tv_cmd->tvc_sgl_count,
+                       sg_bidi_ptr, sg_no_bidi);
        if (rc < 0) {
                transport_send_check_condition_and_sense(se_cmd,
-                               se_cmd->scsi_sense_reason, 0);
+                               TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE, 0);
                transport_generic_free_cmd(se_cmd, 0);
-               return;
        }
-       transport_handle_cdb_direct(se_cmd);
 }
 
 static void vhost_scsi_handle_vq(struct vhost_scsi *vs)

diff --git a/drivers/vhost/tcm_vhost.h b/drivers/vhost/tcm_vhost.h
index d9e9355..7e87c63 100644 (file)
--- a/drivers/vhost/tcm_vhost.h
+++ b/drivers/vhost/tcm_vhost.h
@@ -5,6 +5,12 @@
 struct tcm_vhost_cmd {
        /* Descriptor from vhost_get_vq_desc() for virt_queue segment */
        int tvc_vq_desc;
+       /* virtio-scsi initiator task attribute */
+       int tvc_task_attr;
+       /* virtio-scsi initiator data direction */
+       enum dma_data_direction tvc_data_direction;
+       /* Expected data transfer length from virtio-scsi header */
+       u32 tvc_exp_data_len;
        /* The Tag from include/linux/virtio_scsi.h:struct virtio_scsi_cmd_req */
        u64 tvc_tag;
        /* The number of scatterlists associated with this cmd */
@@ -17,6 +23,8 @@ struct tcm_vhost_cmd {
        struct virtio_scsi_cmd_resp __user *tvc_resp;
        /* Pointer to vhost_scsi for our device */
        struct vhost_scsi *tvc_vhost;
+       /* Pointer to vhost nexus memory */
+       struct tcm_vhost_nexus *tvc_nexus;
        /* The TCM I/O descriptor that is accessed via container_of() */
        struct se_cmd tvc_se_cmd;
        /* work item used for cmwq dispatch to tcm_vhost_submission_work() */