Commit c8712c6a authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe
Browse files

blk-mq: skip unmapped queues in blk_mq_alloc_request_hctx 



This provides the caller a feedback that a given hctx is not mapped and thus
no command can be sent on it.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Tested-by: default avatarSteve Wise <swise@opengridcomputing.com>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent 3b4ac786

block/blk-mq.c

+14 −2
Original line number Diff line number Diff line
@@ -296,17 +296,29 @@ struct request *blk_mq_alloc_request_hctx(struct request_queue *q, int rw, 
	if (ret)

		return ERR_PTR(ret);



	/*

	 * Check if the hardware context is actually mapped to anything.

	 * If not tell the caller that it should skip this queue.

	 */

	hctx = q->queue_hw_ctx[hctx_idx];

	if (!blk_mq_hw_queue_mapped(hctx)) {

		ret = -EXDEV;

		goto out_queue_exit;

	}

	ctx = __blk_mq_get_ctx(q, cpumask_first(hctx->cpumask));



	blk_mq_set_alloc_data(&alloc_data, q, flags, ctx, hctx);

	rq = __blk_mq_alloc_request(&alloc_data, rw, 0);

	if (!rq) {

		blk_queue_exit(q);

		return ERR_PTR(-EWOULDBLOCK);

		ret = -EWOULDBLOCK;

		goto out_queue_exit;

	}



	return rq;



out_queue_exit:

	blk_queue_exit(q);

	return ERR_PTR(ret);

}

EXPORT_SYMBOL_GPL(blk_mq_alloc_request_hctx);