diff mbox series

[V2,2/9] nvme-pci: use blk_mq_max_nr_hw_queues() to calculate io queues

Message ID 20230726094027.535126-3-ming.lei@redhat.com
State Superseded
Headers show
Series blk-mq: fix wrong queue mapping for kdump kernel | expand

Commit Message

Ming Lei July 26, 2023, 9:40 a.m. UTC
Take blk-mq's knowledge into account for calculating io queues.

Fix wrong queue mapping in case of kdump kernel.

On arm and ppc64, 'maxcpus=1' is passed to kdump command line, see
`Documentation/admin-guide/kdump/kdump.rst`, so num_possible_cpus()
still returns all CPUs because 'maxcpus=1' just bring up one single
cpu core during booting.

blk-mq sees single queue in kdump kernel, and in driver's viewpoint
there are still multiple queues, this inconsistency causes driver to apply
wrong queue mapping for handling IO, and IO timeout is triggered.

Meantime, single queue makes much less resource utilization, and reduce
risk of kernel failure.

Reported-by: Wen Xiong <wenxiong@linux.ibm.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
 drivers/nvme/host/pci.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index baf69af7ea78..a1227ae7eb39 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -2251,7 +2251,7 @@  static unsigned int nvme_max_io_queues(struct nvme_dev *dev)
 	 */
 	if (dev->ctrl.quirks & NVME_QUIRK_SHARED_TAGS)
 		return 1;
-	return num_possible_cpus() + dev->nr_write_queues + dev->nr_poll_queues;
+	return blk_mq_max_nr_hw_queues() + dev->nr_write_queues + dev->nr_poll_queues;
 }
 
 static int nvme_setup_io_queues(struct nvme_dev *dev)