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https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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b6139a6abf
group_cpu_evenly() might have allocated less groups then requested:
group_cpu_evenly()
__group_cpus_evenly()
alloc_nodes_groups()
# allocated total groups may be less than numgrps when
# active total CPU number is less then numgrps
In this case, the caller will do an out of bound access because the
caller assumes the masks returned has numgrps.
Return the number of groups created so the caller can limit the access
range accordingly.
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Daniel Wagner <wagi@kernel.org>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20250617-isolcpus-queue-counters-v1-1-13923686b54b@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
93 lines
2.2 KiB
C
93 lines
2.2 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* CPU <-> hardware queue mapping helpers
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*
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* Copyright (C) 2013-2014 Jens Axboe
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*/
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#include <linux/kernel.h>
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#include <linux/threads.h>
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#include <linux/module.h>
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#include <linux/mm.h>
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#include <linux/smp.h>
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#include <linux/cpu.h>
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#include <linux/group_cpus.h>
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#include <linux/device/bus.h>
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#include "blk.h"
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#include "blk-mq.h"
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void blk_mq_map_queues(struct blk_mq_queue_map *qmap)
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{
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const struct cpumask *masks;
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unsigned int queue, cpu, nr_masks;
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masks = group_cpus_evenly(qmap->nr_queues, &nr_masks);
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if (!masks) {
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for_each_possible_cpu(cpu)
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qmap->mq_map[cpu] = qmap->queue_offset;
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return;
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}
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for (queue = 0; queue < qmap->nr_queues; queue++) {
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for_each_cpu(cpu, &masks[queue % nr_masks])
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qmap->mq_map[cpu] = qmap->queue_offset + queue;
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}
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kfree(masks);
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}
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EXPORT_SYMBOL_GPL(blk_mq_map_queues);
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/**
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* blk_mq_hw_queue_to_node - Look up the memory node for a hardware queue index
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* @qmap: CPU to hardware queue map.
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* @index: hardware queue index.
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*
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* We have no quick way of doing reverse lookups. This is only used at
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* queue init time, so runtime isn't important.
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*/
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int blk_mq_hw_queue_to_node(struct blk_mq_queue_map *qmap, unsigned int index)
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{
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int i;
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for_each_possible_cpu(i) {
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if (index == qmap->mq_map[i])
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return cpu_to_node(i);
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}
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return NUMA_NO_NODE;
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}
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/**
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* blk_mq_map_hw_queues - Create CPU to hardware queue mapping
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* @qmap: CPU to hardware queue map
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* @dev: The device to map queues
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* @offset: Queue offset to use for the device
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*
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* Create a CPU to hardware queue mapping in @qmap. The struct bus_type
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* irq_get_affinity callback will be used to retrieve the affinity.
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*/
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void blk_mq_map_hw_queues(struct blk_mq_queue_map *qmap,
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struct device *dev, unsigned int offset)
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{
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const struct cpumask *mask;
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unsigned int queue, cpu;
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if (!dev->bus->irq_get_affinity)
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goto fallback;
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for (queue = 0; queue < qmap->nr_queues; queue++) {
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mask = dev->bus->irq_get_affinity(dev, queue + offset);
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if (!mask)
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goto fallback;
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for_each_cpu(cpu, mask)
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qmap->mq_map[cpu] = qmap->queue_offset + queue;
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}
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return;
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fallback:
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blk_mq_map_queues(qmap);
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}
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EXPORT_SYMBOL_GPL(blk_mq_map_hw_queues);
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