[PATCH 1/8] block: tidy up the bio full checks in bio_add_hw_page

[Christoph Hellwig <hch@lst.de>]

bio_add_hw_page already checks if the number of bytes trying to be added
even fit into max_hw_sectors limit of the queue.   Remove the call to
bio_full and just do a check for the smaller of the number of segments
in the bio and the queue max segments limit, and do this cheap check
before the more expensive gap to previous check.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/bio.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/block/bio.c b/block/bio.c
index 8672179213b939..72488ecea47acf 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -1014,6 +1014,10 @@ int bio_add_hw_page(struct request_queue *q, struct bio *bio,
 		if (bio_try_merge_hw_seg(q, bio, page, len, offset, same_page))
 			return len;
 
+		if (bio->bi_vcnt >=
+		    min(bio->bi_max_vecs, queue_max_segments(q)))
+			return 0;
+
 		/*
 		 * If the queue doesn't support SG gaps and adding this segment
 		 * would create a gap, disallow it.
@@ -1023,12 +1027,6 @@ int bio_add_hw_page(struct request_queue *q, struct bio *bio,
 			return 0;
 	}
 
-	if (bio_full(bio, len))
-		return 0;
-
-	if (bio->bi_vcnt >= queue_max_segments(q))
-		return 0;
-
 	bvec_set_page(&bio->bi_io_vec[bio->bi_vcnt], page, len, offset);
 	bio->bi_vcnt++;
 	bio->bi_iter.bi_size += len;
-- 
2.39.2