On Fri, 2013-05-03 at 10:24 -0400, wenxiong@xxxxxxxxxxxxxxxxxx wrote:
> Quoting Hannes Reinecke <hare@xxxxxxx>:
>
> > 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.
> >
> > Cc: Wen Xiong <wenxiong@xxxxxxxxxxxxxxxxxx>
> > Cc: Brian King <brking@xxxxxxxxxxxxxxxxxx>
> > Signed-off-by: Hannes Reinecke <hare@xxxxxxx>
> >
> Hi James,
>
> I have verified this patch with two new ipr adapters. EEH error can be
> recoery successfully.
> Do you have any question about this new patch?
Yes, it's not correct: stall_for is in jiffies not msec, so
msleep(stall_for) is taking far too long. Plus you don't know that
stall_for is a divisor of timeleft, so timeleft -= stall_for could wrap
and cause the retry loop to go on effectively forever.
I think the below is the correct patch, so I'll commit it unless there
are objections.
James
---
>From a74498dda7acf6f5fb99e43df54f2c1f5c6beec9 Mon Sep 17 00:00:00 2001
From: Hannes Reinecke <hare@xxxxxxx>
Date: Thu, 25 Apr 2013 08:10:00 +0200
Subject: [PATCH] [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]
Cc: Wen Xiong <wenxiong@xxxxxxxxxxxxxxxxxx>
Cc: Brian King <brking@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Hannes Reinecke <hare@xxxxxxx>
Signed-off-by: James Bottomley <JBottomley@xxxxxxxxxxxxx>
diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index c1b05a8..cfd1ef2 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>
@@ -791,22 +792,33 @@ static int scsi_send_eh_cmnd(struct scsi_cmnd *scmd, unsigned char *cmnd,
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 = min(msecs_to_jiffies(10), 1UL);
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;
+ }
+ 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",
@@ -837,7 +849,7 @@ static int scsi_send_eh_cmnd(struct scsi_cmnd *scmd, unsigned char *cmnd,
rtn = FAILED;
break;
}
- } else {
+ } else if (!rtn) {
scsi_abort_eh_cmnd(scmd);
rtn = FAILED;
}
--
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