On 01/19/2017 05:11 PM, Bart Van Assche wrote:
> On Thu, 2017-01-19 at 15:17 +0100, Hannes Reinecke wrote:
>> When we're hitting a busy condition in queuecommand() we need to
>> stop the hardware queue before calling blk_mq_delay_queue(); if
>> we don't blk_mq_delay_queue() will not do anything and requeue
>> will never triggered.
>>
>> Signed-off-by: Hannes Reinecke <hare@xxxxxxxx>
>> ---
>> drivers/scsi/scsi_lib.c | 4 +++-
>> 1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
>> index e9e1e14..4b1cbc6 100644
>> --- a/drivers/scsi/scsi_lib.c
>> +++ b/drivers/scsi/scsi_lib.c
>> @@ -1951,8 +1951,10 @@ static int scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
>> switch (ret) {
>> case BLK_MQ_RQ_QUEUE_BUSY:
>> if (atomic_read(&sdev->device_busy) == 0 &&
>> - !scsi_device_blocked(sdev))
>> + !scsi_device_blocked(sdev)) {
>> + blk_mq_stop_hw_queue(hctx);
>> blk_mq_delay_queue(hctx, SCSI_QUEUE_DELAY);
>> + }
>> break;
>> case BLK_MQ_RQ_QUEUE_ERROR:
>> /*
>
> You may want to add Fixes: 52d7f1b5c2f3 (blk-mq: Avoid that requeueing
> starts stopped queues). See also
> https://www.spinics.net/lists/linux-block/msg06144.html.
>
Yes indeed.
But the powers that be still ponder if it should be fixed in
the SCSI stack or whether it's a generic fix for blk_mq_delay_queue().
Cheers,
Hannes
--
Dr. Hannes Reinecke Teamlead Storage & Networking
hare@xxxxxxx +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: F. Imendörffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton
HRB 21284 (AG Nürnberg)
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