Commit c0053903 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe

blk-mq-pci: add a fallback when pci_irq_get_affinity returns NULL

While pci_irq_get_affinity should never fail for SMP kernel that
implement the affinity mapping, it will always return NULL in the
UP case, so provide a fallback mapping of all queues to CPU 0 in
that case.
Signed-off-by: default avatarChristoph Hellwig <>
Reviewed-by: default avatarOmar Sandoval <>
Signed-off-by: default avatarJens Axboe <>
parent 6caa0503
......@@ -36,12 +36,18 @@ int blk_mq_pci_map_queues(struct blk_mq_tag_set *set, struct pci_dev *pdev)
for (queue = 0; queue < set->nr_hw_queues; queue++) {
mask = pci_irq_get_affinity(pdev, queue);
if (!mask)
return -EINVAL;
goto fallback;
for_each_cpu(cpu, mask)
set->mq_map[cpu] = queue;
return 0;
WARN_ON_ONCE(set->nr_hw_queues > 1);
set->mq_map[cpu] = 0;
return 0;
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