Commit fd03177c authored by Paolo Valente's avatar Paolo Valente Committed by Jens Axboe
Browse files

block, bfq: handle NULL return value by bfq_init_rq() 

As reported in [1], the call bfq_init_rq(rq) may return NULL in case
of OOM (in particular, if rq->elv.icq is NULL because memory
allocation failed in failed in ioc_create_icq()).

This commit handles this circumstance.

[1] https://lkml.org/lkml/2019/7/22/824



Cc: Hsin-Yi Wang <hsinyi@google.com>
Cc: Nicolas Boichat <drinkcat@chromium.org>
Cc: Doug Anderson <dianders@chromium.org>
Reported-by: default avatarGuenter Roeck <linux@roeck-us.net>
Reported-by: default avatarHsin-Yi Wang <hsinyi@google.com>
Reviewed-by: default avatarGuenter Roeck <linux@roeck-us.net>
Signed-off-by: default avatarPaolo Valente <paolo.valente@linaro.org>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 3f758e84

block/bfq-iosched.c

+11 −3
Original line number Diff line number Diff line
@@ -2251,9 +2251,14 @@ static void bfq_request_merged(struct request_queue *q, struct request *req, 
	    blk_rq_pos(container_of(rb_prev(&req->rb_node),

				    struct request, rb_node))) {

		struct bfq_queue *bfqq = bfq_init_rq(req);

		struct bfq_data *bfqd = bfqq->bfqd;

		struct bfq_data *bfqd;

		struct request *prev, *next_rq;



		if (!bfqq)

			return;



		bfqd = bfqq->bfqd;



		/* Reposition request in its sort_list */

		elv_rb_del(&bfqq->sort_list, req);

		elv_rb_add(&bfqq->sort_list, req);
@@ -2300,6 +2305,9 @@ static void bfq_requests_merged(struct request_queue *q, struct request *rq, 
	struct bfq_queue *bfqq = bfq_init_rq(rq),

		*next_bfqq = bfq_init_rq(next);



	if (!bfqq)

		return;



	/*

	 * If next and rq belong to the same bfq_queue and next is older

	 * than rq, then reposition rq in the fifo (by substituting next
@@ -5454,12 +5462,12 @@ static void bfq_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq, 


	spin_lock_irq(&bfqd->lock);

	bfqq = bfq_init_rq(rq);

	if (at_head || blk_rq_is_passthrough(rq)) {

	if (!bfqq || at_head || blk_rq_is_passthrough(rq)) {

		if (at_head)

			list_add(&rq->queuelist, &bfqd->dispatch);

		else

			list_add_tail(&rq->queuelist, &bfqd->dispatch);

	} else { /* bfqq is assumed to be non null here */

	} else {

		idle_timer_disabled = __bfq_insert_request(bfqd, rq);

		/*

		 * Update bfqq, because, if a queue merge has occurred

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