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authorMartin K. Petersen <martin.petersen@oracle.com>2012-02-09 13:48:53 -0500
committerJames Bottomley <JBottomley@Parallels.com>2012-02-19 10:14:52 -0600
commit18a4d0a22ed6c54b67af7718c305cd010f09ddf8 (patch)
tree06e22a92290ff84b2c1d5abb09424493de384c4b /drivers/scsi/scsi_debug.c
parenta78e21dc5e9f896ecee5b1fbe189690dfcca38e1 (diff)
[SCSI] Handle disk devices which can not process medium access commands
We have experienced several devices which fail in a fashion we do not currently handle gracefully in SCSI. After a failure these devices will respond to the SCSI primary command set (INQUIRY, TEST UNIT READY, etc.) but any command accessing the storage medium will time out. The following patch adds an callback that can be used by upper level drivers to inspect the results of an error handling command. This in turn has been used to implement additional checking in the SCSI disk driver. If a medium access command fails twice but TEST UNIT READY succeeds both times in the subsequent error handling we will offline the device. The maximum number of failed commands required to take a device offline can be tweaked in sysfs. Also add a new error flag to scsi_debug which allows this scenario to be easily reproduced. [jejb: fix up integer parsing to use kstrtouint] Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Diffstat (limited to 'drivers/scsi/scsi_debug.c')
-rw-r--r--drivers/scsi/scsi_debug.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index d2fd0efca565..8917154d96c7 100644
--- a/drivers/scsi/scsi_debug.c
+++ b/drivers/scsi/scsi_debug.c
@@ -126,6 +126,7 @@ static const char * scsi_debug_version_date = "20100324";
#define SCSI_DEBUG_OPT_TRANSPORT_ERR 16
#define SCSI_DEBUG_OPT_DIF_ERR 32
#define SCSI_DEBUG_OPT_DIX_ERR 64
+#define SCSI_DEBUG_OPT_MAC_TIMEOUT 128
/* When "every_nth" > 0 then modulo "every_nth" commands:
* - a no response is simulated if SCSI_DEBUG_OPT_TIMEOUT is set
* - a RECOVERED_ERROR is simulated on successful read and write
@@ -3615,6 +3616,9 @@ int scsi_debug_queuecommand_lck(struct scsi_cmnd *SCpnt, done_funct_t done)
scsi_debug_every_nth = -1;
if (SCSI_DEBUG_OPT_TIMEOUT & scsi_debug_opts)
return 0; /* ignore command causing timeout */
+ else if (SCSI_DEBUG_OPT_MAC_TIMEOUT & scsi_debug_opts &&
+ scsi_medium_access_command(SCpnt))
+ return 0; /* time out reads and writes */
else if (SCSI_DEBUG_OPT_RECOVERED_ERR & scsi_debug_opts)
inj_recovered = 1; /* to reads and writes below */
else if (SCSI_DEBUG_OPT_TRANSPORT_ERR & scsi_debug_opts)