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Commit 1356aae0 authored by Akinobu Mita's avatar Akinobu Mita Committed by Jens Axboe
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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: f26cdc85 ("blk-mq: Shared tag enhancements")
Signed-off-by: default avatarAkinobu Mita <akinobu.mita@gmail.com>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Ming Lei <tom.leiming@gmail.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent bda4e0fb

block/blk-mq.c

+8 −1
Original line number Diff line number Diff line
@@ -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)