On 10/01/12 19:41, Dan Williams wrote:
On Thu, Sep 27, 2012 at 9:39 AM, Bart Van Assche <bvanassche@xxxxxxx> wrote:
>> [ ... ]
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 593fc71..03571a3 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1517,10 +1517,6 @@ static void scsi_request_fn(struct request_queue *q)
struct scsi_cmnd *cmd;
struct request *req;
- if(!get_device(&sdev->sdev_gendev))
- /* We must be tearing the block queue down already */
- return;
-
/*
* To start with, we keep looping until the queue is empty, or until
* the host is no longer able to accept any more requests.
@@ -1629,11 +1625,7 @@ out_delay:
if (sdev->device_busy == 0)
blk_delay_queue(q, SCSI_QUEUE_DELAY);
out:
- /* must be careful here...if we trigger the ->remove() function
- * we cannot be holding the q lock */
- spin_unlock_irq(q->queue_lock);
- put_device(&sdev->sdev_gendev);
- spin_lock_irq(q->queue_lock);
+ ;
Any reason to keep this "out:" label now that it has no effect?
Some people prefer a single-exit style for kernel code since that style
makes it easy to add cleanup code for resources allocated inside the
function itself. I don't have a strong opinion about this though.
Note: after I posted this patch series I noticed that patch 2/3 leaves a
(small) race window. I'm currently testing this follow-up patch:
diff --git a/block/blk-core.c b/block/blk-core.c
index f0efe32..3991f8e 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -425,6 +425,9 @@ void blk_drain_queue(struct request_queue *q, bool
drain_all)
}
}
+ if (!drain && blk_queue_dying(q))
+ queue_flag_set(QUEUE_FLAG_DEAD, q);
+
spin_unlock_irq(q->queue_lock);
if (!drain)
@@ -525,10 +528,6 @@ void blk_cleanup_queue(struct request_queue *q)
/* drain all requests queued before DEAD marking */
blk_drain_queue(q, true);
- spin_lock_irq(lock);
- queue_flag_set(QUEUE_FLAG_DEAD, q);
- spin_unlock_irq(lock);
-
/* @q won't process any more request, flush async actions */
del_timer_sync(&q->backing_dev_info.laptop_mode_wb_timer);
blk_sync_queue(q);
--
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