From patchwork Thu Aug 13 21:23:46 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Nicholas A. Bellinger" X-Patchwork-Id: 7011041 Return-Path: X-Original-To: patchwork-linux-fsdevel@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 7467FC05AC for ; Thu, 13 Aug 2015 21:29:19 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 8142320544 for ; Thu, 13 Aug 2015 21:29:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8C8FF2068A for ; Thu, 13 Aug 2015 21:29:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754269AbbHMV3O (ORCPT ); Thu, 13 Aug 2015 17:29:14 -0400 Received: from mail.linux-iscsi.org ([67.23.28.174]:36994 "EHLO linux-iscsi.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752592AbbHMV3M (ORCPT ); Thu, 13 Aug 2015 17:29:12 -0400 Received: from linux-iscsi.org (localhost [127.0.0.1]) by linux-iscsi.org (Postfix) with ESMTP id 3C54722DA5C; Thu, 13 Aug 2015 21:24:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=linux-iscsi.org; s=default.private; t=1439501040; bh=RfrR7SgIltqO4Pdih9AhbOBQf/fyVnR XFmf1ZS3Bi7k=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To: References; b=UzgeQifNiWSMUQ4Ye+VPEvbwr9RFIza8MeHUiEwYIN2KVssRn58U GPyKBOZHrO9yze2fqZQXsZwn6po9YiLBh+t09IhshtHLbHJjPuSfngrRj06PuW2W5Nh CT1oc2hsWypROZyS0wWTRjaJkwTm1eFVueWevBSgXH1qhhdh26Hg= From: "Nicholas A. Bellinger" To: stable Cc: Greg-KH , Al Viro , Miklos Szeredi , linux-fsdevel Subject: [PATCH-v3.14.y 8/8] dcache: don't need rcu in shrink_dentry_list() Date: Thu, 13 Aug 2015 21:23:46 +0000 Message-Id: <1439501026-19955-9-git-send-email-nab@linux-iscsi.org> X-Mailer: git-send-email 1.7.2.5 In-Reply-To: <1439501026-19955-1-git-send-email-nab@linux-iscsi.org> References: <1439501026-19955-1-git-send-email-nab@linux-iscsi.org> Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Spam-Status: No, score=-6.8 required=5.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_HI,RP_MATCHES_RCVD,T_DKIM_INVALID,UNPARSEABLE_RELAY autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Miklos Szeredi commit 60942f2f235ce7b817166cdf355eed729094834d upstream. Since now the shrink list is private and nobody can free the dentry while it is on the shrink list, we can remove RCU protection from this. Signed-off-by: Miklos Szeredi Signed-off-by: Al Viro --- fs/dcache.c | 27 ++++----------------------- 1 file changed, 4 insertions(+), 23 deletions(-) diff --git a/fs/dcache.c b/fs/dcache.c index 0a92385..df323f8 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -797,23 +797,9 @@ static void shrink_dentry_list(struct list_head *list) { struct dentry *dentry, *parent; - rcu_read_lock(); - for (;;) { - dentry = list_entry_rcu(list->prev, struct dentry, d_lru); - if (&dentry->d_lru == list) - break; /* empty */ - - /* - * Get the dentry lock, and re-verify that the dentry is - * this on the shrinking list. If it is, we know that - * DCACHE_SHRINK_LIST and DCACHE_LRU_LIST are set. - */ + while (!list_empty(list)) { + dentry = list_entry(list->prev, struct dentry, d_lru); spin_lock(&dentry->d_lock); - if (dentry != list_entry(list->prev, struct dentry, d_lru)) { - spin_unlock(&dentry->d_lock); - continue; - } - /* * The dispose list is isolated and dentries are not accounted * to the LRU here, so we can simply remove it from the list @@ -829,23 +815,20 @@ static void shrink_dentry_list(struct list_head *list) spin_unlock(&dentry->d_lock); continue; } - rcu_read_unlock(); parent = dentry_kill(dentry, 0); /* * If dentry_kill returns NULL, we have nothing more to do. */ - if (!parent) { - rcu_read_lock(); + if (!parent) continue; - } + if (unlikely(parent == dentry)) { /* * trylocks have failed and d_lock has been held the * whole time, so it could not have been added to any * other lists. Just add it back to the shrink list. */ - rcu_read_lock(); d_shrink_add(dentry, list); spin_unlock(&dentry->d_lock); continue; @@ -859,9 +842,7 @@ static void shrink_dentry_list(struct list_head *list) dentry = parent; while (dentry && !lockref_put_or_lock(&dentry->d_lockref)) dentry = dentry_kill(dentry, 1); - rcu_read_lock(); } - rcu_read_unlock(); } static enum lru_status