Break out several interwined paths when cmd->result is non zero and
place them in scsi_io_completion_nz_result helper function. The logic
is not changed.
Signed-off-by: Douglas Gilbert <dgilbert@xxxxxxxxxxxx>
---
A reviewer requested the original helper function's two return values
be reduced to one: the blk_stat variable. This required a hack to
differentiate the default setting of blk_stat (BLK_STS_OK) from the case
when the helper assigns BLK_STS_OK as the return value. The hack is to
return the otherwise unused BLK_STS_NOTSUPP value as an indication that
the helper didn't change anything.
drivers/scsi/scsi_lib.c | 134 +++++++++++++++++++++++++++++-------------------
1 file changed, 82 insertions(+), 52 deletions(-)
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index a4da5773d42d..9731d0d3cc80 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -751,6 +751,77 @@ static blk_status_t __scsi_error_from_host_byte(struct scsi_cmnd *cmd,
}
}
+/*
+ * Helper for scsi_io_completion() when cmd->result is non-zero. Returns
+ * BLK_STS_NOTSUPP if this function does not change blk_status .
+ */
+static blk_status_t scsi_io_completion_nz_result(struct scsi_cmnd *cmd,
+ int result)
+{
+ bool sense_valid;
+ bool about_current;
+ /* __scsi_error_from_host_byte() does not return BLK_STS_NOTSUPP */
+ blk_status_t blk_stat = BLK_STS_NOTSUPP;
+ struct request *req = cmd->request;
+ struct scsi_sense_hdr sshdr;
+
+ sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
+ about_current = sense_valid ? !scsi_sense_is_deferred(&sshdr) : true;
+
+ 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 (about_current)
+ blk_stat = __scsi_error_from_host_byte(cmd, result);
+ } else if (blk_rq_bytes(req) == 0 && about_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_error_from_host_byte(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);
+ /* 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))
+ blk_stat = BLK_STS_OK;
+
+ return blk_stat;
+}
+
/*
* Function: scsi_io_completion()
*
@@ -794,26 +865,23 @@ 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);
+ blk_stat = scsi_io_completion_nz_result(cmd, result);
+ if (blk_stat == BLK_STS_OK)
+ result = 0; /* suppress error processing now */
+ /*
+ * if scsi_io_completion_nz_result() made no change,
+ * re-instate initial blk_stat value.
+ */
+ if (blk_stat == BLK_STS_NOTSUPP)
+ blk_stat = BLK_STS_OK;
+
}
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_error_from_host_byte(cmd,
- result);
- }
/*
* __scsi_error_from_host_byte may have reset the host_byte
*/
@@ -831,13 +899,6 @@ 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_error_from_host_byte(cmd, result);
}
/* no bidi support for !blk_rq_is_passthrough yet */
@@ -851,37 +912,6 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
"%u sectors total, %d bytes done.\n",
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)) {
- /* 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))
- ;
- else if (!(req->rq_flags & RQF_QUIET))
- 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
--
2.14.1
