1 files changed, 11 insertions, 8 deletions

diff --git a/block/blk-merge.c b/block/blk-merge.c
index b3ac40aef46b..89b97b5e0881 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -97,19 +97,22 @@ void blk_recalc_rq_segments(struct request *rq)
 
 void blk_recount_segments(struct request_queue *q, struct bio *bio)
 {
-        bool no_sg_merge = !!test_bit(QUEUE_FLAG_NO_SG_MERGE,
-                        &q->queue_flags);
-        bool merge_not_need = bio->bi_vcnt < queue_max_segments(q);
+        unsigned short seg_cnt;
+
+        /* estimate segment number by bi_vcnt for non-cloned bio */
+        if (bio_flagged(bio, BIO_CLONED))
+                seg_cnt = bio_segments(bio);
+        else
+                seg_cnt = bio->bi_vcnt;
 
-        if (no_sg_merge && !bio_flagged(bio, BIO_CLONED) &&
-                        merge_not_need)
-                bio->bi_phys_segments = bio->bi_vcnt;
+        if (test_bit(QUEUE_FLAG_NO_SG_MERGE, &q->queue_flags) &&
+                        (seg_cnt < queue_max_segments(q)))
+                bio->bi_phys_segments = seg_cnt;
         else {
                 struct bio *nxt = bio->bi_next;
 
                 bio->bi_next = NULL;
-                bio->bi_phys_segments = __blk_recalc_rq_segments(q, bio,
-                                no_sg_merge && merge_not_need);
+                bio->bi_phys_segments = __blk_recalc_rq_segments(q, bio, false);
                 bio->bi_next = nxt;
         }