vhost/scsi: Convert to se_cmd->cmd_kref TARGET_SCF_ACK_KREF usage

This patch coverts vhost/scsi to se_cmd->cmd_kref TARGET_SCF_ACK_KREF
usage, instead of assuming that vhost_scsi_free_cmd() is always called
before TCM processing is completed in the response fast path.

This includes adding vhost_scsi_check_stop_free() -> target_put_sess_cmd()
to perform the second se_cmd->cmd_kref put, and moving vhost_scsi_free_cmd()
resource release into tcm_vhost_release_cmd() that is invoked once the last
se_cmd->cmd_kref put occurs.

Cc: Christoph Hellwig <hch@lst.de>
Cc: Roland Dreier <roland@kernel.org>
Cc: Kent Overstreet <koverstreet@google.com>
Cc: Asias He <asias@redhat.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Or Gerlitz <ogerlitz@mellanox.com>
Cc: Moussa Ba <moussaba@micron.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

1 files changed, 19 insertions, 12 deletions

diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
index aacf71ea001e..1e5e82042f84 100644
--- a/drivers/vhost/scsi.c
+++ b/drivers/vhost/scsi.c
@@ -446,7 +446,19 @@ static u32 tcm_vhost_tpg_get_inst_index(struct se_portal_group *se_tpg)
 
 static void tcm_vhost_release_cmd(struct se_cmd *se_cmd)
 {
-        return;
+        struct tcm_vhost_cmd *tv_cmd = container_of(se_cmd,
+                                struct tcm_vhost_cmd, tvc_se_cmd);
+
+        if (tv_cmd->tvc_sgl_count) {
+                u32 i;
+                for (i = 0; i < tv_cmd->tvc_sgl_count; i++)
+                        put_page(sg_page(&tv_cmd->tvc_sgl[i]));
+
+                kfree(tv_cmd->tvc_sgl);
+        }
+
+        tcm_vhost_put_inflight(tv_cmd->inflight);
+        kfree(tv_cmd);
 }
 
 static int tcm_vhost_shutdown_session(struct se_session *se_sess)
@@ -559,17 +571,11 @@ static void vhost_scsi_free_cmd(struct tcm_vhost_cmd *tv_cmd)
         /* TODO locking against target/backend threads? */
         transport_generic_free_cmd(se_cmd, 0);
 
-        if (tv_cmd->tvc_sgl_count) {
-                u32 i;
-                for (i = 0; i < tv_cmd->tvc_sgl_count; i++)
-                        put_page(sg_page(&tv_cmd->tvc_sgl[i]));
-
-                kfree(tv_cmd->tvc_sgl);
-        }
-
-        tcm_vhost_put_inflight(tv_cmd->inflight);
+}
 
-        kfree(tv_cmd);
+static int vhost_scsi_check_stop_free(struct se_cmd *se_cmd)
+{
+        return target_put_sess_cmd(se_cmd->se_sess, se_cmd);
 }
 
 static void tcm_vhost_do_evt_work(struct vhost_scsi *vs,
@@ -847,7 +853,7 @@ static void tcm_vhost_submission_work(struct work_struct *work)
                         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,
+                        TARGET_SCF_ACK_KREF, sg_ptr, tv_cmd->tvc_sgl_count,
                         sg_bidi_ptr, sg_no_bidi);
         if (rc < 0) {
                 transport_send_check_condition_and_sense(se_cmd,
@@ -2008,6 +2014,7 @@ static struct target_core_fabric_ops tcm_vhost_ops = {
         .tpg_release_fabric_acl         = tcm_vhost_release_fabric_acl,
         .tpg_get_inst_index             = tcm_vhost_tpg_get_inst_index,
         .release_cmd                    = tcm_vhost_release_cmd,
+        .check_stop_free                = vhost_scsi_check_stop_free,
         .shutdown_session               = tcm_vhost_shutdown_session,
         .close_session                  = tcm_vhost_close_session,
         .sess_get_index                 = tcm_vhost_sess_get_index,