Re: [PATCH 2.6.0-test2] fix broken blk_start_queue behavior

[Jens Axboe <axboe@suse.de>]

On Mon, Jul 28 2003, Lou Langholtz wrote:
> This patch changes the behavior of blk_start_queue() so that request 
> queues really do start up again after blk_start_queue() is called (on 
> queues that were previously stopped via blk_stop_queue). The patch 
> applies against 2.6.0-test2. I have tested this patch with the use of 
> blk_stop_queue and blk_start_queue in my branch of the nbd block device 
> driver (not yet released). blk_start_queue is also used in 
> ./drivers/{block/cciss.c,ide/ide-io.c} which should see things function 
> as intended now w.r.t. stopping and starting the request queue (but I do 
> not know if anybody noticed that they weren't working correctly before). 
> ide-io.c uses queue stop and start for power management handling. Please 
> let me know if you've seen a problem before with that, especially if 
> this patch fixes it - that will be happy news ;-)

> diff -urN linux-2.6.0-test2/drivers/block/ll_rw_blk.c linux-2.6.0-test2-unplug/drivers/block/ll_rw_blk.c
> --- linux-2.6.0-test2/drivers/block/ll_rw_blk.c	2003-07-27 19:02:48.000000000 -0600
> +++ linux-2.6.0-test2-unplug/drivers/block/ll_rw_blk.c	2003-07-28 00:36:35.366537142 -0600
> @@ -1027,10 +1027,10 @@
>   */
>  static inline void __generic_unplug_device(request_queue_t *q)
>  {
> -	if (!blk_remove_plug(q))
> +	if (test_bit(QUEUE_FLAG_STOPPED, &q->queue_flags))
>  		return;
>  
> -	if (test_bit(QUEUE_FLAG_STOPPED, &q->queue_flags))
> +	if (!blk_remove_plug(q))
>  		return;
>  
>  	del_timer(&q->unplug_timer);

Patch looks correct, thanks! Guess our mails crossed in mid-air :)

-- 
Jens Axboe