On Fri, May 04 2018 at 10:36am -0400,
Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> wrote:
> In commit 052189a2ec95 ("dm: remove superfluous irq disablement in
> dm_request_fn") the spin_lock_irq() was replaced with spin_lock() + a
> check for disabled interrupts. Later the locking part was removed in
> commit 2eb6e1e3aa87 ("dm: submit stacked requests in irq enabled
> context") but the BUG_ON() check remained.
>
> Since the original purpose for the "are-irqs-off" check is gone (the
> ->queue_lock has been removed) remove it.
>
> Cc: Keith Busch <keith.busch@xxxxxxxxx>
> Cc: Mike Snitzer <snitzer@xxxxxxxxxx>
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
> ---
> drivers/md/dm-rq.c | 1 -
> 1 file changed, 1 deletion(-)
>
> diff --git a/drivers/md/dm-rq.c b/drivers/md/dm-rq.c
> index bf0b840645cc..1a524f992f72 100644
> --- a/drivers/md/dm-rq.c
> +++ b/drivers/md/dm-rq.c
> @@ -688,7 +688,6 @@ static void dm_old_request_fn(struct request_queue *q)
> /* Establish tio->ti before queuing work (map_tio_request) */
> tio->ti = ti;
> kthread_queue_work(&md->kworker, &tio->work);
> - BUG_ON(!irqs_disabled());
> }
> }
>
> --
> 2.17.0
>
the queue_lock hasn't been removed for the old .request_fn path in block
core -- which dm_old_request_fn is providing the hook for.
This BUG_ON() documents that reality.
Commit 2eb6e1e3aa87 made it such that work is queued into an irq enabled
context. But it never changed the fact that old block core's
.request_fn (and as such dm_old_request_fn) is called with irqs
disabled.
So all said:
Nacked-by: Mike Snitzer <snitzer@xxxxxxxxxx>
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