Re: Strange block/scsi/workqueue issue

From: James Bottomley
Date: Wed Apr 13 2011 - 13:01:28 EST


While you still have the problematic system, can you try this patch? It
avoids changing anything in block (other than to add a missing state
guard for the elv_next_request). If it works, we can defer the sync vs
async discussion and use it for a -stable fix.

Thanks,

James

---

diff --git a/block/blk.h b/block/blk.h
index c8db371..11d0d25 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -62,7 +62,8 @@ static inline struct request *__elv_next_request(struct request_queue *q)
return rq;
}

- if (!q->elevator->ops->elevator_dispatch_fn(q, 0))
+ if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags) ||
+ !q->elevator->ops->elevator_dispatch_fn(q, 0))
return NULL;
}
}
diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
index e44ff64..5aa4246 100644
--- a/drivers/scsi/scsi_sysfs.c
+++ b/drivers/scsi/scsi_sysfs.c
@@ -322,14 +322,9 @@ static void scsi_device_dev_release_usercontext(struct work_struct *work)
kfree(evt);
}

- if (sdev->request_queue) {
- sdev->request_queue->queuedata = NULL;
- /* user context needed to free queue */
- scsi_free_queue(sdev->request_queue);
- /* temporary expedient, try to catch use of queue lock
- * after free of sdev */
- sdev->request_queue = NULL;
- }
+ /* temporary expedient, try to catch use of queue lock after
+ * free of sdev */
+ sdev->request_queue = NULL;

scsi_target_reap(scsi_target(sdev));

@@ -937,6 +932,11 @@ void __scsi_remove_device(struct scsi_device *sdev)
if (sdev->host->hostt->slave_destroy)
sdev->host->hostt->slave_destroy(sdev);
transport_destroy_device(dev);
+ /* Setting this to NULL causes the request function to reject
+ * any I/O requests */
+ sdev->request_queue->queuedata = NULL;
+ /* Freeing the queue signals to block that we're done */
+ scsi_free_queue(sdev->request_queue);
put_device(dev);
}



--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/