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SubjectRe: plug problem in linux-2.4.0-test11


On Wed, 29 Nov 2000, Jens Axboe wrote:
>
> I agree with your reasoning, even if the s390 behaviour is a bit
> "non-standard" wrt block devices. Linus, could you apply?
>
> --- drivers/block/ll_rw_blk.c~ Wed Nov 29 15:17:33 2000
> +++ drivers/block/ll_rw_blk.c Wed Nov 29 15:18:43 2000
> @@ -347,10 +347,9 @@
> */
> static inline void __generic_unplug_device(request_queue_t *q)
> {
> - if (!list_empty(&q->queue_head)) {
> - q->plugged = 0;
> + q->plugged = 0;
> + if (!list_empty(&q->queue_head))
> q->request_fn(q);
> - }
> }

I would much rather actually go back to the original setup, which did
nothing at all if the queue wasn't plugged in the first place.

I think that we should strive for a setup that calls "request_fn" only to
start new IO, and that expects the low-level driver to be able to do the
whole request queue until it is empty. Then we re-start it the next time
around.

Linus

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