From patchwork Thu Jan 7 07:53:11 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wen Yang X-Patchwork-Id: 359737 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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, UNPARSEABLE_RELAY, URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable 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 707ECC433E9 for ; Thu, 7 Jan 2021 07:54:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2AADA23123 for ; Thu, 7 Jan 2021 07:54:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727468AbhAGHyF (ORCPT ); Thu, 7 Jan 2021 02:54:05 -0500 Received: from out30-131.freemail.mail.aliyun.com ([115.124.30.131]:54133 "EHLO out30-131.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727416AbhAGHyE (ORCPT ); Thu, 7 Jan 2021 02:54:04 -0500 X-Alimail-AntiSpam: AC=PASS; BC=-1|-1; BR=01201311R121e4; CH=green; DM=||false|; DS=||; FP=0|-1|-1|-1|0|-1|-1|-1; HT=e01e01424; MF=wenyang@linux.alibaba.com; NM=1; PH=DS; RN=7; SR=0; TI=SMTPD_---0UKzE3St_1610005999; Received: from localhost(mailfrom:wenyang@linux.alibaba.com fp:SMTPD_---0UKzE3St_1610005999) by smtp.aliyun-inc.com(127.0.0.1); Thu, 07 Jan 2021 15:53:19 +0800 From: Wen Yang To: Greg Kroah-Hartman , Sasha Levin Cc: Xunlei Pang , linux-kernel@vger.kernel.org, "Eric W. Biederman" , stable@vger.kernel.org, Wen Yang Subject: [PATCH 4.19 4/7] proc: Generalize proc_sys_prune_dcache into proc_prune_siblings_dcache Date: Thu, 7 Jan 2021 15:53:11 +0800 Message-Id: <20210107075314.62683-5-wenyang@linux.alibaba.com> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20210107075314.62683-1-wenyang@linux.alibaba.com> References: <20210107075314.62683-1-wenyang@linux.alibaba.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: "Eric W. Biederman" [ Upstream commit 26dbc60f385ff9cff475ea2a3bad02e80fd6fa43 ] This prepares the way for allowing the pid part of proc to use this dcache pruning code as well. Signed-off-by: Eric W. Biederman Cc: # 4.19.x Signed-off-by: Wen Yang --- fs/proc/inode.c | 38 ++++++++++++++++++++++++++++++++++++++ fs/proc/internal.h | 1 + fs/proc/proc_sysctl.c | 35 +---------------------------------- 3 files changed, 40 insertions(+), 34 deletions(-) diff --git a/fs/proc/inode.c b/fs/proc/inode.c index e5334ed..fffc7e4 100644 --- a/fs/proc/inode.c +++ b/fs/proc/inode.c @@ -112,6 +112,44 @@ void __init proc_init_kmemcache(void) BUILD_BUG_ON(sizeof(struct proc_dir_entry) >= SIZEOF_PDE); } +void proc_prune_siblings_dcache(struct hlist_head *inodes, spinlock_t *lock) +{ + struct inode *inode; + struct proc_inode *ei; + struct hlist_node *node; + struct super_block *sb; + + rcu_read_lock(); + for (;;) { + node = hlist_first_rcu(inodes); + if (!node) + break; + ei = hlist_entry(node, struct proc_inode, sibling_inodes); + spin_lock(lock); + hlist_del_init_rcu(&ei->sibling_inodes); + spin_unlock(lock); + + inode = &ei->vfs_inode; + sb = inode->i_sb; + if (!atomic_inc_not_zero(&sb->s_active)) + continue; + inode = igrab(inode); + rcu_read_unlock(); + if (unlikely(!inode)) { + deactivate_super(sb); + rcu_read_lock(); + continue; + } + + d_prune_aliases(inode); + iput(inode); + deactivate_super(sb); + + rcu_read_lock(); + } + rcu_read_unlock(); +} + static int proc_show_options(struct seq_file *seq, struct dentry *root) { struct super_block *sb = root->d_sb; diff --git a/fs/proc/internal.h b/fs/proc/internal.h index d922c01..6cae472 100644 --- a/fs/proc/internal.h +++ b/fs/proc/internal.h @@ -210,6 +210,7 @@ struct pde_opener { extern const struct inode_operations proc_pid_link_inode_operations; void proc_init_kmemcache(void); +void proc_prune_siblings_dcache(struct hlist_head *inodes, spinlock_t *lock); void set_proc_pid_nlink(void); extern struct inode *proc_get_inode(struct super_block *, struct proc_dir_entry *); extern int proc_fill_super(struct super_block *, void *data, int flags); diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c index 0f578f6..57b16bf 100644 --- a/fs/proc/proc_sysctl.c +++ b/fs/proc/proc_sysctl.c @@ -264,40 +264,7 @@ static void unuse_table(struct ctl_table_header *p) static void proc_sys_prune_dcache(struct ctl_table_header *head) { - struct inode *inode; - struct proc_inode *ei; - struct hlist_node *node; - struct super_block *sb; - - rcu_read_lock(); - for (;;) { - node = hlist_first_rcu(&head->inodes); - if (!node) - break; - ei = hlist_entry(node, struct proc_inode, sibling_inodes); - spin_lock(&sysctl_lock); - hlist_del_init_rcu(&ei->sibling_inodes); - spin_unlock(&sysctl_lock); - - inode = &ei->vfs_inode; - sb = inode->i_sb; - if (!atomic_inc_not_zero(&sb->s_active)) - continue; - inode = igrab(inode); - rcu_read_unlock(); - if (unlikely(!inode)) { - deactivate_super(sb); - rcu_read_lock(); - continue; - } - - d_prune_aliases(inode); - iput(inode); - deactivate_super(sb); - - rcu_read_lock(); - } - rcu_read_unlock(); + proc_prune_siblings_dcache(&head->inodes, &sysctl_lock); } /* called under sysctl_lock, will reacquire if has to wait */