On 2018/11/21 2:31, Jens Axboe wrote:
> I think the below should fix it, we haven't necessarily setup an
> ioc if we're just doing as passthrough request.
>
>
> diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c
> index 13b8dc332541..f096d8989773 100644
> --- a/block/blk-mq-sched.c
> +++ b/block/blk-mq-sched.c
> @@ -34,9 +34,16 @@ EXPORT_SYMBOL_GPL(blk_mq_sched_free_hctx_data);
> void blk_mq_sched_assign_ioc(struct request *rq)
> {
> struct request_queue *q = rq->q;
> - struct io_context *ioc = current->io_context;
> + struct io_context *ioc;
> struct io_cq *icq;
>
> + /*
> + * May not have an IO context if it's a passthrough request
> + */
> + ioc = current->io_context;
> + if (!ioc)
> + return;
> +
> spin_lock_irq(&q->queue_lock);
> icq = ioc_lookup_icq(ioc, q);
> spin_unlock_irq(&q->queue_lock);
This seems reasonable to me, but I wonder why this problem was not triggering
before. The previous code getting the ioc with the rq_ioc(bio) call was
essentially the same and there was no "if (!ioc) return;" in
blk_mq_sched_assign_ioc() before the patch.
Any idea why this is popping up now ?
Ming,
Is this a new test your are running ? If this same problem triggers on stable
kernels, Jens patch needs to go to stable too.
Best regards.
--
Damien Le Moal
Western Digital Research
