2
0
mirror of https://github.com/edk2-porting/linux-next.git synced 2024-12-24 21:24:00 +08:00
linux-next/block/blk-mq-pci.c
Christoph Hellwig c005390374 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: Christoph Hellwig <hch@lst.de>
Cc: stable@vger.kernel.org
Reviewed-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-08-18 08:08:14 -06:00

54 lines
1.6 KiB
C

/*
* Copyright (c) 2016 Christoph Hellwig.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*/
#include <linux/kobject.h>
#include <linux/blkdev.h>
#include <linux/blk-mq.h>
#include <linux/blk-mq-pci.h>
#include <linux/pci.h>
#include <linux/module.h>
/**
* blk_mq_pci_map_queues - provide a default queue mapping for PCI device
* @set: tagset to provide the mapping for
* @pdev: PCI device associated with @set.
*
* This function assumes the PCI device @pdev has at least as many available
* interrupt vectors as @set has queues. It will then query the vector
* corresponding to each queue for it's affinity mask and built queue mapping
* that maps a queue to the CPUs that have irq affinity for the corresponding
* vector.
*/
int blk_mq_pci_map_queues(struct blk_mq_tag_set *set, struct pci_dev *pdev)
{
const struct cpumask *mask;
unsigned int queue, cpu;
for (queue = 0; queue < set->nr_hw_queues; queue++) {
mask = pci_irq_get_affinity(pdev, queue);
if (!mask)
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);