tcm_loop: TCQ and command abort support

Implement TCQ support, which enables us to do proper command
abort, too.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

2 files changed, 69 insertions, 4 deletions

diff --git a/drivers/target/loopback/tcm_loop.c b/drivers/target/loopback/tcm_loop.c
index 783675f7cdab..04811caac487 100644
--- a/drivers/target/loopback/tcm_loop.c
+++ b/drivers/target/loopback/tcm_loop.c
@@ -135,6 +135,21 @@ static int tcm_loop_change_queue_depth(
         return sdev->queue_depth;
 }
 
+static int tcm_loop_change_queue_type(struct scsi_device *sdev, int tag)
+{
+        if (sdev->tagged_supported) {
+                scsi_set_tag_type(sdev, tag);
+
+                if (tag)
+                        scsi_activate_tcq(sdev, sdev->queue_depth);
+                else
+                        scsi_deactivate_tcq(sdev, sdev->queue_depth);
+        } else
+                tag = 0;
+
+        return tag;
+}
+
 /*
  * Locate the SAM Task Attr from struct scsi_cmnd *
  */
@@ -236,6 +251,7 @@ static int tcm_loop_queuecommand(struct Scsi_Host *sh, struct scsi_cmnd *sc)
         }
 
         tl_cmd->sc = sc;
+        tl_cmd->sc_cmd_tag = sc->tag;
         INIT_WORK(&tl_cmd->work, tcm_loop_submission_work);
         queue_work(tcm_loop_workqueue, &tl_cmd->work);
         return 0;
@@ -247,7 +263,7 @@ static int tcm_loop_queuecommand(struct Scsi_Host *sh, struct scsi_cmnd *sc)
  */
 static int tcm_loop_issue_tmr(struct tcm_loop_tpg *tl_tpg,
                               struct tcm_loop_nexus *tl_nexus,
-                              int lun, enum tcm_tmreq_table tmr)
+                              int lun, int task, enum tcm_tmreq_table tmr)
 {
         struct se_cmd *se_cmd = NULL;
         struct se_session *se_sess;
@@ -283,6 +299,9 @@ static int tcm_loop_issue_tmr(struct tcm_loop_tpg *tl_tpg,
         if (rc < 0)
                 goto release;
 
+        if (tmr == TMR_ABORT_TASK)
+                se_cmd->se_tmr_req->ref_task_tag = task;
+
         /*
          * Locate the underlying TCM struct se_lun
          */
@@ -310,6 +329,36 @@ release:
         return ret;
 }
 
+static int tcm_loop_abort_task(struct scsi_cmnd *sc)
+{
+        struct tcm_loop_hba *tl_hba;
+        struct tcm_loop_nexus *tl_nexus;
+        struct tcm_loop_tpg *tl_tpg;
+        int ret = FAILED;
+
+        /*
+         * Locate the tcm_loop_hba_t pointer
+         */
+        tl_hba = *(struct tcm_loop_hba **)shost_priv(sc->device->host);
+        /*
+         * Locate the tl_nexus and se_sess pointers
+         */
+        tl_nexus = tl_hba->tl_nexus;
+        if (!tl_nexus) {
+                pr_err("Unable to perform device reset without"
+                                " active I_T Nexus\n");
+                return FAILED;
+        }
+
+        /*
+         * Locate the tl_tpg pointer from TargetID in sc->device->id
+         */
+        tl_tpg = &tl_hba->tl_hba_tpgs[sc->device->id];
+        ret = tcm_loop_issue_tmr(tl_tpg, tl_nexus, sc->device->lun,
+                                 sc->tag, TMR_ABORT_TASK);
+        return (ret == TMR_FUNCTION_COMPLETE) ? SUCCESS : FAILED;
+}
+
 /*
  * Called from SCSI EH process context to issue a LUN_RESET TMR
  * to struct scsi_device
@@ -338,8 +387,8 @@ static int tcm_loop_device_reset(struct scsi_cmnd *sc)
          * Locate the tl_tpg pointer from TargetID in sc->device->id
          */
         tl_tpg = &tl_hba->tl_hba_tpgs[sc->device->id];
-        ret = tcm_loop_issue_tmr(tl_tpg, tl_nexus,
-                                 sc->device->lun, TMR_LUN_RESET);
+        ret = tcm_loop_issue_tmr(tl_tpg, tl_nexus, sc->device->lun,
+                                 0, TMR_LUN_RESET);
         return (ret == TMR_FUNCTION_COMPLETE) ? SUCCESS : FAILED;
 }
 
@@ -351,6 +400,15 @@ static int tcm_loop_slave_alloc(struct scsi_device *sd)
 
 static int tcm_loop_slave_configure(struct scsi_device *sd)
 {
+        if (sd->tagged_supported) {
+                scsi_activate_tcq(sd, sd->queue_depth);
+                scsi_adjust_queue_depth(sd, MSG_SIMPLE_TAG,
+                                        sd->host->cmd_per_lun);
+        } else {
+                scsi_adjust_queue_depth(sd, 0,
+                                        sd->host->cmd_per_lun);
+        }
+
         return 0;
 }
 
@@ -360,6 +418,8 @@ static struct scsi_host_template tcm_loop_driver_template = {
         .name                   = "TCM_Loopback",
         .queuecommand           = tcm_loop_queuecommand,
         .change_queue_depth     = tcm_loop_change_queue_depth,
+        .change_queue_type      = tcm_loop_change_queue_type,
+        .eh_abort_handler = tcm_loop_abort_task,
         .eh_device_reset_handler = tcm_loop_device_reset,
         .can_queue              = 1024,
         .this_id                = -1,
@@ -719,7 +779,10 @@ static void tcm_loop_set_default_node_attributes(struct se_node_acl *se_acl)
 
 static u32 tcm_loop_get_task_tag(struct se_cmd *se_cmd)
 {
-        return 1;
+        struct tcm_loop_cmd *tl_cmd = container_of(se_cmd,
+                        struct tcm_loop_cmd, tl_se_cmd);
+
+        return tl_cmd->sc_cmd_tag;
 }
 
 static int tcm_loop_get_cmd_state(struct se_cmd *se_cmd)
diff --git a/drivers/target/loopback/tcm_loop.h b/drivers/target/loopback/tcm_loop.h
index 56528f7dafae..54c59d0b6608 100644
--- a/drivers/target/loopback/tcm_loop.h
+++ b/drivers/target/loopback/tcm_loop.h
@@ -10,6 +10,8 @@
 struct tcm_loop_cmd {
         /* State of Linux/SCSI CDB+Data descriptor */
         u32 sc_cmd_state;
+        /* Tagged command queueing */
+        u32 sc_cmd_tag;
         /* Pointer to the CDB+Data descriptor from Linux/SCSI subsystem */
         struct scsi_cmnd *sc;
         /* The TCM I/O descriptor that is accessed via container_of() */