From: Daniel Wagner Date: Thu, 23 Jan 2025 13:08:29 +0000 (+0100) Subject: blk-mq: create correct map for fallback case X-Git-Tag: nvme-6.14-2025-03-05~23 X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=a9ae6fe1c319c4776c2b11e85e15109cd3f04076;p=nvme.git blk-mq: create correct map for fallback case The fallback code in blk_mq_map_hw_queues is original from blk_mq_pci_map_queues and was added to handle the case where pci_irq_get_affinity will return NULL for !SMP configuration. blk_mq_map_hw_queues replaces besides blk_mq_pci_map_queues also blk_mq_virtio_map_queues which used to use blk_mq_map_queues for the fallback. It's possible to use blk_mq_map_queues for both cases though. blk_mq_map_queues creates the same map as blk_mq_clear_mq_map for !SMP that is CPU 0 will be mapped to hctx 0. The WARN_ON_ONCE has to be dropped for virtio as the fallback is also taken for certain configuration on default. Though there is still a WARN_ON_ONCE check in lib/group_cpus.c: WARN_ON(nr_present + nr_others < numgrps); which will trigger if the caller tries to create more hardware queues than CPUs. It tests the same as the WARN_ON_ONCE in blk_mq_pci_map_queues did. Fixes: a5665c3d150c ("virtio: blk/scsi: replace blk_mq_virtio_map_queues with blk_mq_map_hw_queues") Reported-by: Steven Rostedt Closes: https://lore.kernel.org/all/20250122093020.6e8a4e5b@gandalf.local.home/ Signed-off-by: Daniel Wagner Link: https://lore.kernel.org/r/20250123-fix-blk_mq_map_hw_queues-v1-1-08dbd01f2c39@kernel.org Signed-off-by: Jens Axboe --- diff --git a/block/blk-mq-cpumap.c b/block/blk-mq-cpumap.c index ad8d6a363f24..444798c5374f 100644 --- a/block/blk-mq-cpumap.c +++ b/block/blk-mq-cpumap.c @@ -87,7 +87,6 @@ void blk_mq_map_hw_queues(struct blk_mq_queue_map *qmap, return; fallback: - WARN_ON_ONCE(qmap->nr_queues > 1); - blk_mq_clear_mq_map(qmap); + blk_mq_map_queues(qmap); } EXPORT_SYMBOL_GPL(blk_mq_map_hw_queues);