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authorBart Van Assche <bart.vanassche@sandisk.com>2017-05-24 02:48:42 +0300
committerNicholas Bellinger <nab@linux-iscsi.org>2017-07-07 09:11:25 +0300
commit4c1f0e65397f4e5768b955c32489d5b4b6b92a90 (patch)
tree3253af4701f701b736e5b784bc4eb91d8ee5127f /drivers/target/loopback
parent75f141aaf48e13812b4fee914a66f6fce28b543f (diff)
downloadlinux-4c1f0e65397f4e5768b955c32489d5b4b6b92a90.tar.xz
target/tcm_loop: Make TMF processing slightly faster
Target drivers must guarantee that struct se_cmd and struct se_tmr_req exist as long as target_tmr_work() is in progress. This is why the tcm_loop driver today passes 1 as second argument to transport_generic_free_cmd() from inside the TMF code. Instead of making the TMF code wait, make the TMF code obtain two references (SCF_ACK_KREF) and drop one reference from inside the .check_stop_free() callback. Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Hannes Reinecke <hare@suse.com> Cc: David Disseldorp <ddiss@suse.de> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Diffstat (limited to 'drivers/target/loopback')
-rw-r--r--drivers/target/loopback/tcm_loop.c25
1 files changed, 9 insertions, 16 deletions
diff --git a/drivers/target/loopback/tcm_loop.c b/drivers/target/loopback/tcm_loop.c
index 8cf556b4c5ca..b6a913e38b30 100644
--- a/drivers/target/loopback/tcm_loop.c
+++ b/drivers/target/loopback/tcm_loop.c
@@ -51,19 +51,7 @@ static int tcm_loop_queue_status(struct se_cmd *se_cmd);
*/
static int tcm_loop_check_stop_free(struct se_cmd *se_cmd)
{
- /*
- * Do not release struct se_cmd's containing a valid TMR
- * pointer. These will be released directly in tcm_loop_device_reset()
- * with transport_generic_free_cmd().
- */
- if (se_cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)
- return 0;
- /*
- * Release the struct se_cmd, which will make a callback to release
- * struct tcm_loop_cmd * in tcm_loop_deallocate_core_cmd()
- */
- transport_generic_free_cmd(se_cmd, 0);
- return 1;
+ return transport_generic_free_cmd(se_cmd, 0);
}
static void tcm_loop_release_cmd(struct se_cmd *se_cmd)
@@ -244,18 +232,23 @@ static int tcm_loop_issue_tmr(struct tcm_loop_tpg *tl_tpg,
se_sess = tl_tpg->tl_nexus->se_sess;
rc = target_submit_tmr(se_cmd, se_sess, tl_cmd->tl_sense_buf, lun,
- NULL, tmr, GFP_KERNEL, task, 0 /*flags*/);
+ NULL, tmr, GFP_KERNEL, task,
+ TARGET_SCF_ACK_KREF);
if (rc < 0)
goto release;
wait_for_completion(&tl_cmd->tmr_done);
ret = se_cmd->se_tmr_req->response;
+ target_put_sess_cmd(se_cmd);
+
+out:
+ return ret;
release:
if (se_cmd)
- transport_generic_free_cmd(se_cmd, 1);
+ transport_generic_free_cmd(se_cmd, 0);
else
kmem_cache_free(tcm_loop_cmd_cache, tl_cmd);
- return ret;
+ goto out;
}
static int tcm_loop_abort_task(struct scsi_cmnd *sc)