From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.6 required=3.0 tests=DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID, URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B1435C43142 for ; Thu, 28 Jun 2018 13:27:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6A28B27441 for ; Thu, 28 Jun 2018 13:27:26 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="KLVz1hRt" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6A28B27441 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966177AbeF1N1L (ORCPT ); Thu, 28 Jun 2018 09:27:11 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:49834 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753810AbeF1N1A (ORCPT ); Thu, 28 Jun 2018 09:27:00 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=References:In-Reply-To:Message-Id: Date:Subject:Cc:To:From:Sender:Reply-To:MIME-Version:Content-Type: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=u4kDLeHjogkxVPPVZFNy9kKBP7gADz5yfE3nU2RpLJo=; b=KLVz1hRths1n4WTeVTTqGJK2t Ev8IDk13/KY3TAsGJb/bzDePKbQmBPG7n2NLj5trNNsNxcZMSAJcR966IhGwaDskvfVC35Aa+Fi2J 4c2RjvICRJIsA436ORPGwdOBPWhat62r6U9CFCrsw46h+Dh9dngTFsrdQUJwPgPz7nmfYwvvMuACF HS41moSHM49JPB1ZI5Ugui8yj+0eHfA8LbmTfc3ztp2NvzWSNr5XRj36Nr1Jf08S0sL0XZfI1+R96 ZHobmpSjqYxsZaSUUF8DDcpsExzfLGrZqGqzyreemSAhSPGQ5uo3x/7ftWxc1lEGKIKJni3GBa9ZD XKFWsSw/g==; Received: from willy by bombadil.infradead.org with local (Exim 4.90_1 #2 (Red Hat Linux)) id 1fYWwt-0000rr-HV; Thu, 28 Jun 2018 13:26:59 +0000 From: Matthew Wilcox To: v9fs-developer@lists.sourceforge.net Cc: linux-fsdevel@vger.kernel.org, Eric Van Hensbergen , Ron Minnich , Latchesar Ionkov , linux-kernel@vger.kernel.org, Matthew Wilcox Subject: [PATCH 4/6] 9p: Remove an unnecessary memory barrier Date: Thu, 28 Jun 2018 06:26:27 -0700 Message-Id: <20180628132629.3148-5-willy@infradead.org> X-Mailer: git-send-email 2.14.4 In-Reply-To: <20180628132629.3148-1-willy@infradead.org> References: <20180628132629.3148-1-willy@infradead.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org And add a comment about why we don't need it. Signed-off-by: Matthew Wilcox --- net/9p/client.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) diff --git a/net/9p/client.c b/net/9p/client.c index 602f76de388a..2dce8d8307cc 100644 --- a/net/9p/client.c +++ b/net/9p/client.c @@ -436,13 +436,9 @@ void p9_client_cb(struct p9_client *c, struct p9_req_t *req, int status) { p9_debug(P9_DEBUG_MUX, " tag %d\n", req->tc->tag); - /* - * This barrier is needed to make sure any change made to req before - * the other thread wakes up will indeed be seen by the waiting side. - */ - smp_wmb(); req->status = status; + /* wake_up is an implicit write memory barrier */ wake_up(&req->wq); p9_debug(P9_DEBUG_MUX, "wakeup: %d\n", req->tc->tag); } -- 2.18.0