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scsi: core: scsi_io_completion hints on fastpath

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

Signed-off-by: Douglas Gilbert <dgilbert@interlog.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Bart Van Assche <bart.vanassche@wdc.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This commit is contained in:
Douglas Gilbert 2018-06-23 12:22:19 +02:00 committed by Martin K. Petersen
parent 4ae61c68f7
commit 0d437906f6
1 changed files with 9 additions and 9 deletions
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18
drivers/scsi/scsi_lib.c
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@ -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)) {
/* Kill remainder if no retries. */
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);