scsi: core: add scsi_io_completion_nz_result function

Break out several intertwined paths when cmd->result is non zero and place
them in the scsi_io_completion_nz_result helper function. The logic is not
changed.

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>

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 1da1ff4..0289240 100644 (file)
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -762,6 +762,79 @@ static blk_status_t scsi_result_to_blk_status(struct scsi_cmnd *cmd, int result)
 }
 
 /*
+ * Helper for scsi_io_completion() when cmd->result is non-zero. Returns a
+ * new result that may suppress further error checking. Also modifies
+ * *blk_statp in some cases.
+ */
+static int scsi_io_completion_nz_result(struct scsi_cmnd *cmd, int result,
+                                       blk_status_t *blk_statp)
+{
+       bool sense_valid;
+       bool sense_current = true;      /* false implies "deferred sense" */
+       struct request *req = cmd->request;
+       struct scsi_sense_hdr sshdr;
+
+       sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
+       if (sense_valid)
+               sense_current = !scsi_sense_is_deferred(&sshdr);
+
+       if (blk_rq_is_passthrough(req)) {
+               if (sense_valid) {
+                       /*
+                        * SG_IO wants current and deferred errors
+                        */
+                       scsi_req(req)->sense_len =
+                               min(8 + cmd->sense_buffer[7],
+                                   SCSI_SENSE_BUFFERSIZE);
+               }
+               if (sense_current)
+                       *blk_statp = scsi_result_to_blk_status(cmd, result);
+       } else if (blk_rq_bytes(req) == 0 && sense_current) {
+               /*
+                * Flush commands do not transfers any data, and thus cannot use
+                * good_bytes != blk_rq_bytes(req) as the signal for an error.
+                * This sets *blk_statp explicitly for the problem case.
+                */
+               *blk_statp = scsi_result_to_blk_status(cmd, result);
+       }
+       /*
+        * Recovered errors need reporting, but they're always treated as
+        * success, so fiddle the result code here.  For passthrough requests
+        * we already took a copy of the original into sreq->result which
+        * is what gets returned to the user
+        */
+       if (sense_valid && (sshdr.sense_key == RECOVERED_ERROR)) {
+               bool do_print = true;
+               /*
+                * if ATA PASS-THROUGH INFORMATION AVAILABLE [0x0, 0x1d]
+                * skip print since caller wants ATA registers. Only occurs
+                * on SCSI ATA PASS_THROUGH commands when CK_COND=1
+                */
+               if ((sshdr.asc == 0x0) && (sshdr.ascq == 0x1d))
+                       do_print = false;
+               else if (req->rq_flags & RQF_QUIET)
+                       do_print = false;
+               if (do_print)
+                       scsi_print_sense(cmd);
+               result = 0;
+               /* for passthrough, *blk_statp may be set */
+               *blk_statp = BLK_STS_OK;
+       }
+       /*
+        * Another corner case: the SCSI status byte is non-zero but 'good'.
+        * Example: PRE-FETCH command returns SAM_STAT_CONDITION_MET when
+        * it is able to fit nominated LBs in its cache (and SAM_STAT_GOOD
+        * if it can't fit). Treat SAM_STAT_CONDITION_MET and the related
+        * intermediate statuses (both obsolete in SAM-4) as good.
+        */
+       if (status_byte(result) && scsi_status_is_good(result)) {
+               result = 0;
+               *blk_statp = BLK_STS_OK;
+       }
+       return result;
+}
+
+/*
  * Function:    scsi_io_completion()
  *
  * Purpose:     Completion processing for block device I/O requests.
@@ -804,26 +877,14 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
              ACTION_DELAYED_RETRY} action;
        unsigned long wait_for = (cmd->allowed + 1) * req->timeout;
 
-       if (result) {
+       if (result) {   /* does not necessarily mean there is an error */
                sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
                if (sense_valid)
                        sense_current = !scsi_sense_is_deferred(&sshdr);
+               result = scsi_io_completion_nz_result(cmd, result, &blk_stat);
        }
 
        if (blk_rq_is_passthrough(req)) {
-               if (result) {
-                       if (sense_valid) {
-                               /*
-                                * SG_IO wants current and deferred errors
-                                */
-                               scsi_req(req)->sense_len =
-                                       min(8 + cmd->sense_buffer[7],
-                                           SCSI_SENSE_BUFFERSIZE);
-                       }
-                       if (sense_current)
-                               blk_stat = scsi_result_to_blk_status(cmd,
-                                                                      result);
-               }
                /*
                 * scsi_result_to_blk_status may have reset the host_byte
                 */
@@ -841,13 +902,6 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
                                BUG();
                        return;
                }
-       } else if (blk_rq_bytes(req) == 0 && result && sense_current) {
-               /*
-                * Flush commands do not transfers any data, and thus cannot use
-                * good_bytes != blk_rq_bytes(req) as the signal for an error.
-                * This sets blk_stat explicitly for the problem case.
-                */
-               blk_stat = scsi_result_to_blk_status(cmd, result);
        }
 
        /* no bidi support for !blk_rq_is_passthrough yet */
@@ -862,42 +916,6 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
                blk_rq_sectors(req), good_bytes));
 
        /*
-        * Recovered errors need reporting, but they're always treated as
-        * success, so fiddle the result code here.  For passthrough requests
-        * we already took a copy of the original into sreq->result which
-        * is what gets returned to the user
-        */
-       if (sense_valid && (sshdr.sense_key == RECOVERED_ERROR)) {
-               bool do_print = true;
-
-               /*
-                * If ATA PASS-THROUGH INFORMATION AVAILABLE skip
-                * print since caller wants ATA registers. Only occurs on
-                * SCSI ATA PASS_THROUGH commands when CK_COND=1
-                */
-               if ((sshdr.asc == 0x0) && (sshdr.ascq == 0x1d))
-                       do_print = false;
-               else if (req->rq_flags & RQF_QUIET)
-                       do_print = false;
-               if (do_print)
-                       scsi_print_sense(cmd);
-               result = 0;
-               /* for passthrough, blk_stat may be set */
-               blk_stat = BLK_STS_OK;
-       }
-       /*
-        * Another corner case: the SCSI status byte is non-zero but 'good'.
-        * Example: PRE-FETCH command returns SAM_STAT_CONDITION_MET when
-        * it is able to fit nominated LBs in its cache (and SAM_STAT_GOOD
-        * if it can't fit). Treat SAM_STAT_CONDITION_MET and the related
-        * intermediate statuses (both obsolete in SAM-4) as good.
-        */
-       if (status_byte(result) && scsi_status_is_good(result)) {
-               result = 0;
-               blk_stat = BLK_STS_OK;
-       }
-
-       /*
         * Next deal with any sectors which we were able to correctly
         * handle. Failed, zero length commands always need to drop down
         * to retry code. Fast path should return in this block.