[SCSI] Handle MLQUEUE busy response in scsi_send_eh_cmnd
scsi_send_eh_cmnd() is calling queuecommand() directly, so
it needs to check the return value here.
The only valid return codes for queuecommand() are 'busy'
states, so we need to wait for a bit to allow the LLDD
to recover.
Based on an earlier patch from Wen Xiong.
[jejb: fix confusion between msec and jiffies values and other issues]
[bvanassche: correct stall_for interval]
Cc: Wen Xiong <wenxiong@linux.vnet.ibm.com>
Cc: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index c1b05a8..f43de1e 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -25,6 +25,7 @@
#include <linux/interrupt.h>
#include <linux/blkdev.h>
#include <linux/delay.h>
+#include <linux/jiffies.h>
#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>
@@ -791,32 +792,48 @@
struct scsi_device *sdev = scmd->device;
struct Scsi_Host *shost = sdev->host;
DECLARE_COMPLETION_ONSTACK(done);
- unsigned long timeleft;
+ unsigned long timeleft = timeout;
struct scsi_eh_save ses;
+ const unsigned long stall_for = msecs_to_jiffies(100);
int rtn;
+retry:
scsi_eh_prep_cmnd(scmd, &ses, cmnd, cmnd_size, sense_bytes);
shost->eh_action = &done;
scsi_log_send(scmd);
scmd->scsi_done = scsi_eh_done;
- shost->hostt->queuecommand(shost, scmd);
-
- timeleft = wait_for_completion_timeout(&done, timeout);
+ rtn = shost->hostt->queuecommand(shost, scmd);
+ if (rtn) {
+ if (timeleft > stall_for) {
+ scsi_eh_restore_cmnd(scmd, &ses);
+ timeleft -= stall_for;
+ msleep(jiffies_to_msecs(stall_for));
+ goto retry;
+ }
+ /* signal not to enter either branch of the if () below */
+ timeleft = 0;
+ rtn = NEEDS_RETRY;
+ } else {
+ timeleft = wait_for_completion_timeout(&done, timeout);
+ }
shost->eh_action = NULL;
- scsi_log_completion(scmd, SUCCESS);
+ scsi_log_completion(scmd, rtn);
SCSI_LOG_ERROR_RECOVERY(3,
printk("%s: scmd: %p, timeleft: %ld\n",
__func__, scmd, timeleft));
/*
- * If there is time left scsi_eh_done got called, and we will
- * examine the actual status codes to see whether the command
- * actually did complete normally, else tell the host to forget
- * about this command.
+ * If there is time left scsi_eh_done got called, and we will examine
+ * the actual status codes to see whether the command actually did
+ * complete normally, else if we have a zero return and no time left,
+ * the command must still be pending, so abort it and return FAILED.
+ * If we never actually managed to issue the command, because
+ * ->queuecommand() kept returning non zero, use the rtn = FAILED
+ * value above (so don't execute either branch of the if)
*/
if (timeleft) {
rtn = scsi_eh_completed_normally(scmd);
@@ -837,7 +854,7 @@
rtn = FAILED;
break;
}
- } else {
+ } else if (!rtn) {
scsi_abort_eh_cmnd(scmd);
rtn = FAILED;
}
