James,
Our testing has encountered an error between sdev initialization/
scanning and the sdev block/unblock behavior. What we have seen is that
new target detection will kick off a scan, and that an sdev will be in
the creation process with the state SDEV_CREATED. At this point a link
event occurs, which blocks the sdev, changes its state to SDEV_BLOCK,
and stops its request queue. However, the creation thread is still
executing, and decides to transition the sdev state to SDEV_RUNNING.
Note that the request queue is still blocked. The sdev then gets unblocked,
attempting to change the state to SDEV_RUNNING, which fails as it is already
SDEV_RUNNING, which causes the unblock routine to bypass the call to
blk_start_queue().
This patch modifies the creation path so that it only changes to SDEV_RUNNING
if the state is SDEV_CREATED. This allows the block/unblock to work
appropriately. It does have a side effect that unblock could early-transition
the sdev to SDEV_RUNNING.
-- bino
Signed-off-by: Bino Sebastian <[EMAIL PROTECTED]>
diff -upNr a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
--- a/drivers/scsi/scsi_scan.c 2006-11-20 16:40:21.977901000 -0500
+++ b/drivers/scsi/scsi_scan.c 2006-11-21 09:08:41.232680000 -0500
@@ -762,7 +762,8 @@ static int scsi_add_lun(struct scsi_devi
/* set the device running here so that slave configure
* may do I/O */
- scsi_device_set_state(sdev, SDEV_RUNNING);
+ if (sdev->sdev_state == SDEV_CREATED)
+ scsi_device_set_state(sdev, SDEV_RUNNING);
if (*bflags & BLIST_MS_192_BYTES_FOR_3F)
sdev->use_192_bytes_for_3f = 1;
diff -upNr a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
--- a/drivers/scsi/scsi_sysfs.c 2006-11-20 16:40:21.988903000 -0500
+++ b/drivers/scsi/scsi_sysfs.c 2006-11-21 09:08:41.245680000 -0500
@@ -676,7 +676,8 @@ int scsi_sysfs_add_sdev(struct scsi_devi
{
int error, i;
- if ((error = scsi_device_set_state(sdev, SDEV_RUNNING)) != 0)
+ if ((sdev->sdev_state == SDEV_CREATED) &&
+ ((error = scsi_device_set_state(sdev, SDEV_RUNNING)) != 0))
return error;
error = device_add(&sdev->sdev_gendev);
-
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