On Tue, 2012-06-26 at 06:46 +0000, Bart Van Assche wrote: > On 06/25/12 21:14, James Bottomley wrote: > > > On Mon, 2012-06-25 at 18:15 +0000, Bart Van Assche wrote: > >> diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c > >> index 6dfb978..c26ef49 100644 > >> --- a/drivers/scsi/scsi_lib.c > >> +++ b/drivers/scsi/scsi_lib.c > >> @@ -406,10 +406,7 @@ static void scsi_run_queue(struct request_queue *q) > >> LIST_HEAD(starved_list); > >> unsigned long flags; > >> > >> - /* if the device is dead, sdev will be NULL, so no queue to run */ > >> - if (!sdev) > >> - return; > >> - > >> + BUG_ON(!sdev); > > > > Needs to be a blk_queue_dead() check as well. > > > Callers of scsi_run_queue() don't hold the queue lock. Does it make > sense to test whether the queue is dead without the queue lock being held ? I'm not entirely sure I understand the question, but I think you think that locking is required to read the queue state? That's emphatically not correct. In fact, you don't even need locking to write the state provied the state variable is a natcural processor witdth (i.e. u32 on 32 bit or u64 or u32 on 64 bit) and you don't do dependent state variable updates or other atomic sequences. James -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
