block: Remove should_sort judgement when flush blk_plug

In commit 975927b942c932,it add blk_rq_pos to sort rq when flushing.
Although this commit was used for the situation which blk_plug handled
multi devices on the same time like md device.
I think there must be some situations like this but only single
device.
So remove the should_sort judgement.
Because the parameter should_sort is only for this purpose,it can delete
should_sort from blk_plug.

CC: Shaohua Li <shli@kernel.org>
Signed-off-by: Jianpeng Ma <majianpeng@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 1 insertions, 12 deletions

diff --git a/block/blk-core.c b/block/blk-core.c
index c973249d68cd..aca5d82ff13c 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1548,13 +1548,6 @@ get_rq:
                 if (list_empty(&plug->list))
                         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);
@@ -2888,7 +2881,6 @@ void blk_start_plug(struct blk_plug *plug)
         plug->magic = PLUG_MAGIC;
         INIT_LIST_HEAD(&plug->list);
         INIT_LIST_HEAD(&plug->cb_list);
-        plug->should_sort = 0;
 
         /*
          * If this is a nested plug, don't actually assign it. It will be
@@ -2990,10 +2982,7 @@ void blk_flush_plug_list(struct blk_plug *plug, bool from_schedule)
 
         list_splice_init(&plug->list, &list);
 
-        if (plug->should_sort) {
-                list_sort(NULL, &list, plug_rq_cmp);
-                plug->should_sort = 0;
-        }
+        list_sort(NULL, &list, plug_rq_cmp);
 
         q = NULL;
         depth = 0;