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blk-mq: avoid setting hctx->tags->cpumask before allocation 

When unmapped hw queue is remapped after CPU topology is changed,
hctx->tags->cpumask has to be set after hctx->tags is setup in
blk_mq_map_swqueue(), otherwise it causes null pointer dereference.

Fixes: f26cdc8536 ("blk-mq: Shared tag enhancements")
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Ming Lei <tom.leiming@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Akinobu Mita 2015-09-27 02:09:19 +09:00 committed by Jens Axboe
parent bda4e0fb31
commit 1356aae083
1 changed files with 8 additions and 1 deletions
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9
block/blk-mq.c
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@ -1811,7 +1811,6 @@ static void blk_mq_map_swqueue(struct request_queue *q)
hctx = q->mq_ops->map_queue(q, i);
cpumask_set_cpu(i, hctx->cpumask);
cpumask_set_cpu(i, hctx->tags->cpumask);
ctx->index_hw = hctx->nr_ctx;
hctx->ctxs[hctx->nr_ctx++] = ctx;
}
@ -1851,6 +1850,14 @@ static void blk_mq_map_swqueue(struct request_queue *q)
hctx->next_cpu = cpumask_first(hctx->cpumask);
hctx->next_cpu_batch = BLK_MQ_CPU_WORK_BATCH;
}
queue_for_each_ctx(q, ctx, i) {
if (!cpu_online(i))
continue;
hctx = q->mq_ops->map_queue(q, i);
cpumask_set_cpu(i, hctx->tags->cpumask);
}
}
static void blk_mq_update_tag_set_depth(struct blk_mq_tag_set *set)