SD Cardreaders (especially) sometimes lose the state during suspend
and deliver a "media changed" unit attention when really only a
(runtime) suspend/resume cycle has been done.
For such devices, I/O fails when runtime PM is enabled, see below.
That's the motivation to add this flag. If set by a driver the
one following MEDIA CHANGE unit attention will be ignored.
Signed-off-by: Martin Kepplinger <martin.kepplinger@xxxxxxx>
---
drivers/scsi/scsi_error.c | 36 +++++++++++++++++++++++++++++++-----
include/scsi/scsi_device.h | 1 +
2 files changed, 32 insertions(+), 5 deletions(-)
diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index 08c06c56331c..c62915d34ba4 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -585,6 +585,18 @@ int scsi_check_sense(struct scsi_cmnd *scmd)
return NEEDS_RETRY;
}
}
+ if (scmd->device->expecting_media_change) {
+ if (sshdr.asc == 0x28 && sshdr.ascq == 0x00) {
+ /*
+ * clear the expecting_media_change in
+ * scsi_decide_disposition() because we
+ * need to catch possible "fail fast" overrides
+ * that block readahead can cause.
+ */
+ return NEEDS_RETRY;
+ }
+ }
+
/*
* we might also expect a cc/ua if another LUN on the target
* reported a UA with an ASC/ASCQ of 3F 0E -
@@ -1977,14 +1989,28 @@ int scsi_decide_disposition(struct scsi_cmnd *scmd)
* the request was not marked fast fail. Note that above,
* even if the request is marked fast fail, we still requeue
* for queue congestion conditions (QUEUE_FULL or BUSY) */
- if (scsi_cmd_retry_allowed(scmd) && !scsi_noretry_cmd(scmd)) {
- return NEEDS_RETRY;
- } else {
- /*
- * no more retries - report this one back to upper level.
+ if (scsi_cmd_retry_allowed(scmd)) {
+ /* but scsi_noretry_cmd() cannot override the
+ * expecting_media_change flag.
*/
+ if (!scsi_noretry_cmd(scmd) ||
+ scmd->device->expecting_media_change) {
+ scmd->device->expecting_media_change = 0;
+ return NEEDS_RETRY;
+ }
+
+ /* Not marked fail fast, or marked but not expected.
+ * Clear the flag too because it's meant for the
+ * next UA only.
+ */
+ scmd->device->expecting_media_change = 0;
return SUCCESS;
}
+
+ /*
+ * no more retries - report this one back to upper level.
+ */
+ return SUCCESS;
}
static void eh_lock_door_done(struct request *req, blk_status_t status)
diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
index 05c7c320ef32..926b42ce1dc4 100644
--- a/include/scsi/scsi_device.h
+++ b/include/scsi/scsi_device.h
@@ -171,6 +171,7 @@ struct scsi_device {
* this device */
unsigned expecting_cc_ua:1; /* Expecting a CHECK_CONDITION/UNIT_ATTN
* because we did a bus reset. */
+ unsigned expecting_media_change:1; /* Expecting "media changed" UA */
unsigned use_10_for_rw:1; /* first try 10-byte read / write */
unsigned use_10_for_ms:1; /* first try 10-byte mode sense/select */
unsigned set_dbd_for_ms:1; /* Set "DBD" field in mode sense */
--
2.30.2
