This is a note to let you know that I've just added the patch titled
blk-mq-pci: add a fallback when pci_irq_get_affinity returns NULL
to the 4.12-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
blk-mq-pci-add-a-fallback-when-pci_irq_get_affinity-returns-null.patch
and it can be found in the queue-4.12 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From c005390374957baacbc38eef96ea360559510aa7 Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@xxxxxx>
Date: Thu, 17 Aug 2017 12:24:47 +0200
Subject: blk-mq-pci: add a fallback when pci_irq_get_affinity returns NULL
From: Christoph Hellwig <hch@xxxxxx>
commit c005390374957baacbc38eef96ea360559510aa7 upstream.
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: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: Omar Sandoval <osandov@xxxxxx>
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
block/blk-mq-pci.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
--- a/block/blk-mq-pci.c
+++ b/block/blk-mq-pci.c
@@ -36,12 +36,18 @@ int blk_mq_pci_map_queues(struct blk_mq_
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;
+
+fallback:
+ WARN_ON_ONCE(set->nr_hw_queues > 1);
+ for_each_possible_cpu(cpu)
+ set->mq_map[cpu] = 0;
+ return 0;
}
EXPORT_SYMBOL_GPL(blk_mq_pci_map_queues);
Patches currently in stable-queue which might be from hch@xxxxxx are
queue-4.12/blk-mq-pci-add-a-fallback-when-pci_irq_get_affinity-returns-null.patch