blk-mq: add a flags parameter to blk_mq_alloc_request

We already have the reserved flag, and a nowait flag awkwardly encoded as
a gfp_t.  Add a real flags argument to make the scheme more extensible and
allow for a nicer calling convention.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/block/blk-core.c b/block/blk-core.c
index c88a946..5ec9960 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -630,7 +630,7 @@
 }
 EXPORT_SYMBOL(blk_alloc_queue);
 
-int blk_queue_enter(struct request_queue *q, gfp_t gfp)
+int blk_queue_enter(struct request_queue *q, bool nowait)
 {
 	while (true) {
 		int ret;
@@ -638,7 +638,7 @@
 		if (percpu_ref_tryget_live(&q->q_usage_counter))
 			return 0;
 
-		if (!gfpflags_allow_blocking(gfp))
+		if (nowait)
 			return -EBUSY;
 
 		ret = wait_event_interruptible(q->mq_freeze_wq,
@@ -1276,7 +1276,9 @@
 struct request *blk_get_request(struct request_queue *q, int rw, gfp_t gfp_mask)
 {
 	if (q->mq_ops)
-		return blk_mq_alloc_request(q, rw, gfp_mask, false);
+		return blk_mq_alloc_request(q, rw,
+			(gfp_mask & __GFP_DIRECT_RECLAIM) ?
+				0 : BLK_MQ_REQ_NOWAIT);
 	else
 		return blk_old_get_request(q, rw, gfp_mask);
 }
@@ -2044,8 +2046,7 @@
 	do {
 		struct request_queue *q = bdev_get_queue(bio->bi_bdev);
 
-		if (likely(blk_queue_enter(q, __GFP_DIRECT_RECLAIM) == 0)) {
-
+		if (likely(blk_queue_enter(q, false) == 0)) {
 			ret = q->make_request_fn(q, bio);
 
 			blk_queue_exit(q);