Eric Lee / smarc-fsl-linux-kernel

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Commit 0d437906f6dca6167b37c8e1f6f6ec395bde6230

Authored by Douglas Gilbert
Committed by Martin K. Petersen
1 parent 4ae61c68f7

scsi: core: scsi_io_completion hints on fastpath 

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>

Showing 1 changed file with 9 additions and 9 deletions Side-by-side Diff

drivers/scsi/scsi_lib.c
Diff comments   View file @ 0d43790
... ... @@ -1042,17 +1042,17 @@
1042 1042 struct request *req = cmd->request;
1043 1043 blk_status_t blk_stat = BLK_STS_OK;
1044 1044  
1045   - if (result) /* does not necessarily mean there is an error */
  1045 + if (unlikely(result)) /* a nz result may or may not be an error */
1046 1046 result = scsi_io_completion_nz_result(cmd, result, &blk_stat);
1047 1047  
1048   - if (blk_rq_is_passthrough(req)) {
  1048 + if (unlikely(blk_rq_is_passthrough(req))) {
1049 1049 /*
1050 1050 * scsi_result_to_blk_status may have reset the host_byte
1051 1051 */
1052 1052 scsi_req(req)->result = cmd->result;
1053 1053 scsi_req(req)->resid_len = scsi_get_resid(cmd);
1054 1054  
1055   - if (scsi_bidi_cmnd(cmd)) {
  1055 + if (unlikely(scsi_bidi_cmnd(cmd))) {
1056 1056 /*
1057 1057 * Bidi commands Must be complete as a whole,
1058 1058 * both sides at once.
... ... @@ -1065,7 +1065,7 @@
1065 1065 }
1066 1066 }
1067 1067  
1068   - /* no bidi support for !blk_rq_is_passthrough yet */
  1068 + /* no bidi support yet, other than in pass-through */
1069 1069 BUG_ON(blk_bidi_rq(req));
1070 1070  
1071 1071 /*
1072 1072  
... ... @@ -1081,13 +1081,13 @@
1081 1081 * handle. Failed, zero length commands always need to drop down
1082 1082 * to retry code. Fast path should return in this block.
1083 1083 */
1084   - if (blk_rq_bytes(req) > 0 || blk_stat == BLK_STS_OK) {
1085   - if (!scsi_end_request(req, blk_stat, good_bytes, 0))
  1084 + if (likely(blk_rq_bytes(req) > 0 || blk_stat == BLK_STS_OK)) {
  1085 + if (likely(!scsi_end_request(req, blk_stat, good_bytes, 0)))
1086 1086 return; /* no bytes remaining */
1087 1087 }
1088 1088  
1089   - /* Kill remainder if no retries. */
1090   - if (blk_stat && scsi_noretry_cmd(cmd)) {
  1089 + /* Kill remainder if no retries. */
  1090 + if (unlikely(blk_stat && scsi_noretry_cmd(cmd))) {
1091 1091 if (scsi_end_request(req, blk_stat, blk_rq_bytes(req), 0))
1092 1092 BUG();
1093 1093 return;
... ... @@ -1097,7 +1097,7 @@
1097 1097 * If there had been no error, but we have leftover bytes in the
1098 1098 * requeues just queue the command up again.
1099 1099 */
1100   - if (result == 0)
  1100 + if (likely(result == 0))
1101 1101 scsi_io_completion_reprep(cmd, q);
1102 1102 else
1103 1103 scsi_io_completion_action(cmd, result);