From patchwork Tue Sep 4 16:06:21 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jan Kara X-Patchwork-Id: 10587573 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id CA50714BD for ; Tue, 4 Sep 2018 16:06:46 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id C7B8829D70 for ; Tue, 4 Sep 2018 16:06:46 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id BC3B529DC7; Tue, 4 Sep 2018 16:06:46 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 499FA29DC8 for ; Tue, 4 Sep 2018 16:06:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727798AbeIDUca (ORCPT ); Tue, 4 Sep 2018 16:32:30 -0400 Received: from mx2.suse.de ([195.135.220.15]:54574 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727693AbeIDUc3 (ORCPT ); Tue, 4 Sep 2018 16:32:29 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id A6311B03F; Tue, 4 Sep 2018 16:06:41 +0000 (UTC) Received: by quack2.suse.cz (Postfix, from userid 1000) id 2BCDD1E0A33; Tue, 4 Sep 2018 18:06:41 +0200 (CEST) From: Jan Kara To: Paul Moore Cc: Al Viro , linux-audit@redhat.com, , rgb@redhat.com, Amir Goldstein , Jan Kara Subject: [PATCH 01/11] audit_tree: Remove mark->lock locking Date: Tue, 4 Sep 2018 18:06:21 +0200 Message-Id: <20180904160632.21210-2-jack@suse.cz> X-Mailer: git-send-email 2.16.4 In-Reply-To: <20180904160632.21210-1-jack@suse.cz> References: <20180904160632.21210-1-jack@suse.cz> Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Currently, audit_tree code uses mark->lock to protect against detaching of mark from an inode. In most places it however also uses mark->group->mark_mutex (as we need to atomically replace attached marks) and this provides protection against mark detaching as well. So just remove protection with mark->lock from audit tree code and replace it with mark->group->mark_mutex protection in all the places. It simplifies the code and gets rid of some ugly catches like calling fsnotify_add_mark_locked() with mark->lock held (which cannot sleep only because we hold a reference to another mark attached to the same inode). Signed-off-by: Jan Kara --- kernel/audit_tree.c | 24 ++++-------------------- 1 file changed, 4 insertions(+), 20 deletions(-) diff --git a/kernel/audit_tree.c b/kernel/audit_tree.c index ea43181cde4a..1b55b1026a36 100644 --- a/kernel/audit_tree.c +++ b/kernel/audit_tree.c @@ -193,7 +193,7 @@ static inline struct list_head *chunk_hash(unsigned long key) return chunk_hash_heads + n % HASH_SIZE; } -/* hash_lock & entry->lock is held by caller */ +/* hash_lock & entry->group->mark_mutex is held by caller */ static void insert_hash(struct audit_chunk *chunk) { unsigned long key = chunk_to_key(chunk); @@ -256,13 +256,11 @@ static void untag_chunk(struct node *p) new = alloc_chunk(size); mutex_lock(&entry->group->mark_mutex); - spin_lock(&entry->lock); /* * mark_mutex protects mark from getting detached and thus also from * mark->connector->obj getting NULL. */ if (chunk->dead || !(entry->flags & FSNOTIFY_MARK_FLAG_ATTACHED)) { - spin_unlock(&entry->lock); mutex_unlock(&entry->group->mark_mutex); if (new) fsnotify_put_mark(&new->mark); @@ -280,7 +278,6 @@ static void untag_chunk(struct node *p) list_del_init(&p->list); list_del_rcu(&chunk->hash); spin_unlock(&hash_lock); - spin_unlock(&entry->lock); mutex_unlock(&entry->group->mark_mutex); fsnotify_destroy_mark(entry, audit_tree_group); goto out; @@ -323,7 +320,6 @@ static void untag_chunk(struct node *p) list_for_each_entry(owner, &new->trees, same_root) owner->root = new; spin_unlock(&hash_lock); - spin_unlock(&entry->lock); mutex_unlock(&entry->group->mark_mutex); fsnotify_destroy_mark(entry, audit_tree_group); fsnotify_put_mark(&new->mark); /* drop initial reference */ @@ -340,7 +336,6 @@ static void untag_chunk(struct node *p) p->owner = NULL; put_tree(owner); spin_unlock(&hash_lock); - spin_unlock(&entry->lock); mutex_unlock(&entry->group->mark_mutex); out: fsnotify_put_mark(entry); @@ -360,12 +355,12 @@ static int create_chunk(struct inode *inode, struct audit_tree *tree) return -ENOSPC; } - spin_lock(&entry->lock); + mutex_lock(&entry->group->mark_mutex); spin_lock(&hash_lock); if (tree->goner) { spin_unlock(&hash_lock); chunk->dead = 1; - spin_unlock(&entry->lock); + mutex_unlock(&entry->group->mark_mutex); fsnotify_destroy_mark(entry, audit_tree_group); fsnotify_put_mark(entry); return 0; @@ -380,7 +375,7 @@ static int create_chunk(struct inode *inode, struct audit_tree *tree) } insert_hash(chunk); spin_unlock(&hash_lock); - spin_unlock(&entry->lock); + mutex_unlock(&entry->group->mark_mutex); fsnotify_put_mark(entry); /* drop initial reference */ return 0; } @@ -421,14 +416,12 @@ static int tag_chunk(struct inode *inode, struct audit_tree *tree) chunk_entry = &chunk->mark; mutex_lock(&old_entry->group->mark_mutex); - spin_lock(&old_entry->lock); /* * mark_mutex protects mark from getting detached and thus also from * mark->connector->obj getting NULL. */ if (!(old_entry->flags & FSNOTIFY_MARK_FLAG_ATTACHED)) { /* old_entry is being shot, lets just lie */ - spin_unlock(&old_entry->lock); mutex_unlock(&old_entry->group->mark_mutex); fsnotify_put_mark(old_entry); fsnotify_put_mark(&chunk->mark); @@ -437,23 +430,16 @@ static int tag_chunk(struct inode *inode, struct audit_tree *tree) if (fsnotify_add_mark_locked(chunk_entry, old_entry->connector->obj, FSNOTIFY_OBJ_TYPE_INODE, 1)) { - spin_unlock(&old_entry->lock); mutex_unlock(&old_entry->group->mark_mutex); fsnotify_put_mark(chunk_entry); fsnotify_put_mark(old_entry); return -ENOSPC; } - /* even though we hold old_entry->lock, this is safe since chunk_entry->lock could NEVER have been grabbed before */ - spin_lock(&chunk_entry->lock); spin_lock(&hash_lock); - - /* we now hold old_entry->lock, chunk_entry->lock, and hash_lock */ if (tree->goner) { spin_unlock(&hash_lock); chunk->dead = 1; - spin_unlock(&chunk_entry->lock); - spin_unlock(&old_entry->lock); mutex_unlock(&old_entry->group->mark_mutex); fsnotify_destroy_mark(chunk_entry, audit_tree_group); @@ -485,8 +471,6 @@ static int tag_chunk(struct inode *inode, struct audit_tree *tree) list_add(&tree->same_root, &chunk->trees); } spin_unlock(&hash_lock); - spin_unlock(&chunk_entry->lock); - spin_unlock(&old_entry->lock); mutex_unlock(&old_entry->group->mark_mutex); fsnotify_destroy_mark(old_entry, audit_tree_group); fsnotify_put_mark(chunk_entry); /* drop initial reference */