diff mbox series

[V3,10/14] scsi: pm8001: take blk_mq_max_nr_hw_queues() into account for calculating io vectors

Message ID 20230808104239.146085-11-ming.lei@redhat.com
State New
Headers show
Series blk-mq: fix wrong queue mapping for kdump kernel | expand

Commit Message

Ming Lei Aug. 8, 2023, 10:42 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 kernel 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.

Acked-by: Jack Wang <jinpu.wang@ionos.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
 drivers/scsi/pm8001/pm8001_init.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/drivers/scsi/pm8001/pm8001_init.c b/drivers/scsi/pm8001/pm8001_init.c
index 4995e1ef4e0e..220ae504e5a5 100644
--- a/drivers/scsi/pm8001/pm8001_init.c
+++ b/drivers/scsi/pm8001/pm8001_init.c
@@ -965,6 +965,8 @@  static u32 pm8001_setup_msix(struct pm8001_hba_info *pm8001_ha)
 		rc = pci_alloc_irq_vectors(pm8001_ha->pdev, 1, 1,
 					   PCI_IRQ_MSIX);
 	} else {
+		unsigned int max_vecs = min_t(unsigned int, PM8001_MAX_MSIX_VEC,
+				scsi_max_nr_hw_queues() + 1);
 		/*
 		 * Queue index #0 is used always for housekeeping, so don't
 		 * include in the affinity spreading.
@@ -973,7 +975,7 @@  static u32 pm8001_setup_msix(struct pm8001_hba_info *pm8001_ha)
 			.pre_vectors = 1,
 		};
 		rc = pci_alloc_irq_vectors_affinity(
-				pm8001_ha->pdev, 2, PM8001_MAX_MSIX_VEC,
+				pm8001_ha->pdev, 2, max_vecs,
 				PCI_IRQ_MSIX | PCI_IRQ_AFFINITY, &desc);
 	}