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Commit 6d2809d5 authored by Omar Sandoval's avatar Omar Sandoval Committed by Jens Axboe
Browse files

blk-mq: make blk_mq_alloc_request_hctx() allocate a scheduler request 



blk_mq_alloc_request_hctx() allocates a driver request directly, unlike
its blk_mq_alloc_request() counterpart. It also crashes because it
doesn't update the tags->rqs map.

Fix it by making it allocate a scheduler request.

Reported-by: default avatarSagi Grimberg <sagi@grimberg.me>
Signed-off-by: default avatarOmar Sandoval <osandov@fb.com>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
Tested-by: default avatarSagi Grimberg <sagi@grimberg.me>
parent 415b806d

block/blk-mq-sched.c

+5 −6
Original line number Diff line number Diff line
@@ -110,15 +110,14 @@ struct request *blk_mq_sched_get_request(struct request_queue *q, 
					 struct blk_mq_alloc_data *data)

{

	struct elevator_queue *e = q->elevator;

	struct blk_mq_hw_ctx *hctx;

	struct blk_mq_ctx *ctx;

	struct request *rq;



	blk_queue_enter_live(q);

	ctx = blk_mq_get_ctx(q);

	hctx = blk_mq_map_queue(q, ctx->cpu);



	blk_mq_set_alloc_data(data, q, data->flags, ctx, hctx);

	data->q = q;

	if (likely(!data->ctx))

		data->ctx = blk_mq_get_ctx(q);

	if (likely(!data->hctx))

		data->hctx = blk_mq_map_queue(q, data->ctx->cpu);



	if (e) {

		data->flags |= BLK_MQ_REQ_INTERNAL;

block/blk-mq.c

+15 −18
Original line number Diff line number Diff line
@@ -273,10 +273,9 @@ EXPORT_SYMBOL(blk_mq_alloc_request); 
struct request *blk_mq_alloc_request_hctx(struct request_queue *q, int rw,

		unsigned int flags, unsigned int hctx_idx)

{

	struct blk_mq_hw_ctx *hctx;

	struct blk_mq_ctx *ctx;

	struct blk_mq_alloc_data alloc_data = { .flags = flags };

	struct request *rq;

	struct blk_mq_alloc_data alloc_data;

	unsigned int cpu;

	int ret;



	/*
@@ -299,25 +298,23 @@ struct request *blk_mq_alloc_request_hctx(struct request_queue *q, int rw, 
	 * 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);

	if (!rq) {

		ret = -EWOULDBLOCK;

		goto out_queue_exit;

	alloc_data.hctx = q->queue_hw_ctx[hctx_idx];

	if (!blk_mq_hw_queue_mapped(alloc_data.hctx)) {

		blk_queue_exit(q);

		return ERR_PTR(-EXDEV);

	}

	cpu = cpumask_first(alloc_data.hctx->cpumask);

	alloc_data.ctx = __blk_mq_get_ctx(q, cpu);



	return rq;

	rq = blk_mq_sched_get_request(q, NULL, rw, &alloc_data);



out_queue_exit:

	blk_mq_put_ctx(alloc_data.ctx);

	blk_queue_exit(q);

	return ERR_PTR(ret);



	if (!rq)

		return ERR_PTR(-EWOULDBLOCK);



	return rq;

}

EXPORT_SYMBOL_GPL(blk_mq_alloc_request_hctx);