From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757009AbaEJRC0 (ORCPT ); Sat, 10 May 2014 13:02:26 -0400 Received: from mail-pd0-f175.google.com ([209.85.192.175]:33513 "EHLO mail-pd0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754728AbaEJRCW (ORCPT ); Sat, 10 May 2014 13:02:22 -0400 From: Ming Lei To: Jens Axboe , linux-kernel@vger.kernel.org Cc: Ming Lei Subject: [PATCH 2/5] blk-mq: bitmap tag: remove barrier in bt_clear_tag() Date: Sun, 11 May 2014 01:01:49 +0800 Message-Id: <1399741312-10453-3-git-send-email-tom.leiming@gmail.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1399741312-10453-1-git-send-email-tom.leiming@gmail.com> References: <1399741312-10453-1-git-send-email-tom.leiming@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The barrier isn't necessary because both atomic_dec_and_test() and wake_up() implicate one barrier. Signed-off-by: Ming Lei --- block/blk-mq-tag.c | 1 - 1 file changed, 1 deletion(-) diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c index b8b968d..777aad7 100644 --- a/block/blk-mq-tag.c +++ b/block/blk-mq-tag.c @@ -243,7 +243,6 @@ static void bt_clear_tag(struct blk_mq_bitmap_tags *bt, unsigned int tag) bs = bt_wake_ptr(bt); if (bs && atomic_dec_and_test(&bs->wait_cnt)) { - smp_mb__after_clear_bit(); atomic_set(&bs->wait_cnt, BT_WAIT_BATCH); bt_index_inc(&bt->wake_index); wake_up(&bs->wait); -- 1.7.9.5