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Commit 4c1f0e65 authored by Bart Van Assche's avatar Bart Van Assche Committed by Nicholas Bellinger
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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: default avatarBart 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: default avatarNicholas Bellinger <nab@linux-iscsi.org>
parent 75f141aa

drivers/target/loopback/tcm_loop.c

+9 −16
Original line number Diff line number Diff line
@@ -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)