[PATCH 1/3] block: avoid unnecessary plug should_sort test.

[Jianpeng Ma]

If request_count >= BLK_MAX_REQUEST_COUNT,then it will exec
blk_flush_plug_list which plug all request.So no need to do plug->should_sort 
test.

Signed-off-by: Jianpeng Ma <majianp...@gmail.com>
---
 block/blk-core.c |    9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index 4b4dbdf..7a3abc6 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1514,17 +1514,16 @@ get_rq:
                if (list_empty(&plug->list))
                        trace_block_plug(q);
                else {
-                       if (!plug->should_sort) {
+                       if (request_count >= BLK_MAX_REQUEST_COUNT) {
+                               blk_flush_plug_list(plug, false);
+                               trace_block_plug(q);
+                       } else if (!plug->should_sort) {
                                struct request *__rq;
 
                                __rq = list_entry_rq(plug->list.prev);
                                if (__rq->q != q)
                                        plug->should_sort = 1;
                        }
-                       if (request_count >= BLK_MAX_REQUEST_COUNT) {
-                               blk_flush_plug_list(plug, false);
-                               trace_block_plug(q);
-                       }
                }
                list_add_tail(&req->queuelist, &plug->list);
                drive_stat_acct(req, 1);
-- 
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