On Sun, Feb 02, 2020 at 06:20:04PM +0800, Hillf Danton wrote: > > Select the current cpu if it's mapped to hardware to make helpers like > blk_mq_rq_cpu() return correct value. > > Signed-off-by: Hillf Danton <hdanton@xxxxxxxx> > --- > > --- a/block/blk-mq.c > +++ b/block/blk-mq.c > @@ -454,7 +454,10 @@ struct request *blk_mq_alloc_request_hct > blk_queue_exit(q); > return ERR_PTR(-EXDEV); > } > - cpu = cpumask_first_and(alloc_data.hctx->cpumask, cpu_online_mask); > + cpu = raw_smp_processor_id(); > + if (!cpumask_test_cpu(cpu, alloc_data.hctx->cpumask)) > + cpu = cpumask_first_and(alloc_data.hctx->cpumask, > + cpu_online_mask); How can you know if there is any online CPU available for this hctx? > alloc_data.ctx = __blk_mq_get_ctx(q, cpu); > > rq = blk_mq_get_request(q, NULL, &alloc_data); > It is really one NVMe specific issue, see the following discussion: https://lore.kernel.org/linux-block/8f4402a0-967d-f12d-2f1a-949e1dda017c@xxxxxxxxxxx/#r Thanks, Ming
