1 files changed, 24 insertions, 70 deletions

diff --git a/block/blk-core.c b/block/blk-core.c
index 1bf83a0df0f6..8340f69670d8 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -282,35 +282,6 @@ void blk_set_queue_dying(struct request_queue *q)
 }
 EXPORT_SYMBOL_GPL(blk_set_queue_dying);
 
-/* Unconfigure the I/O scheduler and dissociate from the cgroup controller. */
-void blk_exit_queue(struct request_queue *q)
-{
-	/*
-	 * Since the I/O scheduler exit code may access cgroup information,
-	 * perform I/O scheduler exit before disassociating from the block
-	 * cgroup controller.
-	 */
-	if (q->elevator) {
-		ioc_clear_queue(q);
-		elevator_exit(q, q->elevator);
-		q->elevator = NULL;
-	}
-
-	/*
-	 * Remove all references to @q from the block cgroup controller before
-	 * restoring @q->queue_lock to avoid that restoring this pointer causes
-	 * e.g. blkcg_print_blkgs() to crash.
-	 */
-	blkcg_exit_queue(q);
-
-	/*
-	 * Since the cgroup code may dereference the @q->backing_dev_info
-	 * pointer, only decrease its reference count after having removed the
-	 * association with the block cgroup controller.
-	 */
-	bdi_put(q->backing_dev_info);
-}
-
 /**
  * blk_cleanup_queue - shutdown a request queue
  * @q: request queue to shutdown
@@ -346,17 +317,22 @@ void blk_cleanup_queue(struct request_queue *q)
 	del_timer_sync(&q->backing_dev_info->laptop_mode_wb_timer);
 	blk_sync_queue(q);
 
-	/*
-	 * I/O scheduler exit is only safe after the sysfs scheduler attribute
-	 * has been removed.
-	 */
-	WARN_ON_ONCE(q->kobj.state_in_sysfs);
-
-	blk_exit_queue(q);
-
 	if (queue_is_mq(q))
 		blk_mq_exit_queue(q);
 
+	/*
+	 * In theory, request pool of sched_tags belongs to request queue.
+	 * However, the current implementation requires tag_set for freeing
+	 * requests, so free the pool now.
+	 *
+	 * Queue has become frozen, there can't be any in-queue requests, so
+	 * it is safe to free requests now.
+	 */
+	mutex_lock(&q->sysfs_lock);
+	if (q->elevator)
+		blk_mq_sched_free_requests(q);
+	mutex_unlock(&q->sysfs_lock);
+
 	percpu_ref_exit(&q->q_usage_counter);
 
 	/* @q is and will stay empty, shutdown and put */
@@ -994,22 +970,8 @@ blk_qc_t generic_make_request(struct bio *bio)
 	 * yet.
 	 */
 	struct bio_list bio_list_on_stack[2];
-	blk_mq_req_flags_t flags = 0;
-	struct request_queue *q = bio->bi_disk->queue;
 	blk_qc_t ret = BLK_QC_T_NONE;
 
-	if (bio->bi_opf & REQ_NOWAIT)
-		flags = BLK_MQ_REQ_NOWAIT;
-	if (bio_flagged(bio, BIO_QUEUE_ENTERED))
-		blk_queue_enter_live(q);
-	else if (blk_queue_enter(q, flags) < 0) {
-		if (!blk_queue_dying(q) && (bio->bi_opf & REQ_NOWAIT))
-			bio_wouldblock_error(bio);
-		else
-			bio_io_error(bio);
-		return ret;
-	}
-
 	if (!generic_make_request_checks(bio))
 		goto out;
 
@@ -1046,22 +1008,11 @@ blk_qc_t generic_make_request(struct bio *bio)
 	bio_list_init(&bio_list_on_stack[0]);
 	current->bio_list = bio_list_on_stack;
 	do {
-		bool enter_succeeded = true;
-
-		if (unlikely(q != bio->bi_disk->queue)) {
-			if (q)
-				blk_queue_exit(q);
-			q = bio->bi_disk->queue;
-			flags = 0;
-			if (bio->bi_opf & REQ_NOWAIT)
-				flags = BLK_MQ_REQ_NOWAIT;
-			if (blk_queue_enter(q, flags) < 0) {
-				enter_succeeded = false;
-				q = NULL;
-			}
-		}
+		struct request_queue *q = bio->bi_disk->queue;
+		blk_mq_req_flags_t flags = bio->bi_opf & REQ_NOWAIT ?
+			BLK_MQ_REQ_NOWAIT : 0;
 
-		if (enter_succeeded) {
+		if (likely(blk_queue_enter(q, flags) == 0)) {
 			struct bio_list lower, same;
 
 			/* Create a fresh bio_list for all subordinate requests */
@@ -1069,6 +1020,8 @@ blk_qc_t generic_make_request(struct bio *bio)
 			bio_list_init(&bio_list_on_stack[0]);
 			ret = q->make_request_fn(q, bio);
 
+			blk_queue_exit(q);
+
 			/* sort new bios into those for a lower level
 			 * and those for the same level
 			 */
@@ -1095,8 +1048,6 @@ blk_qc_t generic_make_request(struct bio *bio)
 	current->bio_list = NULL; /* deactivate */
 
 out:
-	if (q)
-		blk_queue_exit(q);
 	return ret;
 }
 EXPORT_SYMBOL(generic_make_request);
@@ -1200,7 +1151,9 @@ static int blk_cloned_rq_check_limits(struct request_queue *q,
 				      struct request *rq)
 {
 	if (blk_rq_sectors(rq) > blk_queue_get_max_sectors(q, req_op(rq))) {
-		printk(KERN_ERR "%s: over max size limit.\n", __func__);
+		printk(KERN_ERR "%s: over max size limit. (%u > %u)\n",
+			__func__, blk_rq_sectors(rq),
+			blk_queue_get_max_sectors(q, req_op(rq)));
 		return -EIO;
 	}
 
@@ -1212,7 +1165,8 @@ static int blk_cloned_rq_check_limits(struct request_queue *q,
 	 */
 	blk_recalc_rq_segments(rq);
 	if (rq->nr_phys_segments > queue_max_segments(q)) {
-		printk(KERN_ERR "%s: over max segments limit.\n", __func__);
+		printk(KERN_ERR "%s: over max segments limit. (%hu > %hu)\n",
+			__func__, rq->nr_phys_segments, queue_max_segments(q));
 		return -EIO;
 	}