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Commit 0d437906 authored by Douglas Gilbert's avatar Douglas Gilbert Committed by Martin K. Petersen
Browse files

scsi: core: scsi_io_completion hints on fastpath 



Add likely() and unlikely() hints to conditionals on or near the fastpath.

Signed-off-by: default avatarDouglas Gilbert <dgilbert@interlog.com>
Reviewed-by: default avatarJohannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: default avatarBart Van Assche <bart.vanassche@wdc.com>
Reviewed-by: default avatarHannes Reinecke <hare@suse.com>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent 4ae61c68

drivers/scsi/scsi_lib.c

+9 −9
Original line number Diff line number Diff line
@@ -1042,17 +1042,17 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes) 
	struct request *req = cmd->request;

	blk_status_t blk_stat = BLK_STS_OK;



	if (result)	/* does not necessarily mean there is an error */

	if (unlikely(result))	/* a nz result may or may not be an error */

		result = scsi_io_completion_nz_result(cmd, result, &blk_stat);



	if (blk_rq_is_passthrough(req)) {

	if (unlikely(blk_rq_is_passthrough(req))) {

		/*

		 * scsi_result_to_blk_status may have reset the host_byte

		 */

		scsi_req(req)->result = cmd->result;

		scsi_req(req)->resid_len = scsi_get_resid(cmd);



		if (scsi_bidi_cmnd(cmd)) {

		if (unlikely(scsi_bidi_cmnd(cmd))) {

			/*

			 * Bidi commands Must be complete as a whole,

			 * both sides at once.
@@ -1065,7 +1065,7 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes) 
		}

	}



	/* no bidi support for !blk_rq_is_passthrough yet */

	/* no bidi support yet, other than in pass-through */

	BUG_ON(blk_bidi_rq(req));



	/*
@@ -1081,13 +1081,13 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes) 
	 * handle. Failed, zero length commands always need to drop down

	 * to retry code. Fast path should return in this block.

	 */

	if (blk_rq_bytes(req) > 0 || blk_stat == BLK_STS_OK) {

		if (!scsi_end_request(req, blk_stat, good_bytes, 0))

	if (likely(blk_rq_bytes(req) > 0 || blk_stat == BLK_STS_OK)) {

		if (likely(!scsi_end_request(req, blk_stat, good_bytes, 0)))

			return; /* no bytes remaining */

	}



	/* Kill remainder if no retries. */

	if (blk_stat && scsi_noretry_cmd(cmd)) {

	if (unlikely(blk_stat && scsi_noretry_cmd(cmd))) {

		if (scsi_end_request(req, blk_stat, blk_rq_bytes(req), 0))

			BUG();

		return;
@@ -1097,7 +1097,7 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes) 
	 * If there had been no error, but we have leftover bytes in the

	 * requeues just queue the command up again.

	 */

	if (result == 0)

	if (likely(result == 0))

		scsi_io_completion_reprep(cmd, q);

	else

		scsi_io_completion_action(cmd, result);