From 4c1f0e65397f4e5768b955c32489d5b4b6b92a90 Mon Sep 17 00:00:00 2001 From: Bart Van Assche Date: Tue, 23 May 2017 16:48:42 -0700 Subject: [PATCH] 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 Cc: Christoph Hellwig Cc: Hannes Reinecke Cc: David Disseldorp Signed-off-by: Nicholas Bellinger --- drivers/target/loopback/tcm_loop.c | 25 +++++++++---------------- 1 file 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) -- 2.39.5