From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from zeniv.linux.org.uk (zeniv.linux.org.uk [62.89.141.173]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C4783241CB7; Sun, 9 Nov 2025 06:37:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=62.89.141.173 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762670271; cv=none; b=WhimD6NFy9vGr+Hznf5psU6X330eTuZPBwAhJChfixSB+ygcjpe/iyJrdCHCmy9jLxgSwZG5+4Owhxa5PFq51DqOZ1EeV3iIplTgcVlcvL+ZT5zu36zKfTTEfREds+gug8scgXzHsab0bP8WHrE7bvpqXufhHU4fx18MuKmGH9k= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762670271; c=relaxed/simple; bh=YXvExZ6nFYMYGW5Yow8JrqcueNyhJE1qx9yl2S9CFNI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=kVVsyTw0a6OYhNPxwnEmVd8orRGUYvf0hRyfvfFPzad/lQ4MaNh8cc081B53C8Eg6EpHNZL3VDkJnvvZgWpxLfeKczIYfcii1G9rmH9nebClzJjaHnnbcBjzXODrXyiolOTxBsy8D14hBmWR/LXx5qun97LCdYVcFFIg+xDom/Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zeniv.linux.org.uk; spf=none smtp.mailfrom=ftp.linux.org.uk; dkim=pass (2048-bit key) header.d=linux.org.uk header.i=@linux.org.uk header.b=t7ZoDXsb; arc=none smtp.client-ip=62.89.141.173 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zeniv.linux.org.uk Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=ftp.linux.org.uk Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linux.org.uk header.i=@linux.org.uk header.b="t7ZoDXsb" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=linux.org.uk; s=zeniv-20220401; h=Sender:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description; bh=2OVGejaTIaqTifOZGRFKTB6zyUq35WGbXMjA6hnZtbo=; b=t7ZoDXsbxeLWCoY8yjMq5se07Q bcSED/P0dXfRD+NsKjJP6B2IfQvTyLXF/hnkOb/+k0Fc9LohkOBMjKYwlZebDDxGS8WA9QuK1I4Z+ SZilhrZDcdYetf5fUwGLSXge2fbcdMKq5pKqey0GChiBJuwMWha52uQ69o67Enh+oRcdD9AwGfCUS lEBh/9HKU0miOH8luLnlAc6HvHxqP01J2eQMDV8ENZ+H4aQmNynkFAv7vD0TTYCc1s69EUvOVpGIF NZovAt+r61Fy7uxMKLTBscBtlzI8kFwu/xf9ZgLM0Rp6CwT2ggNqWJXdEMzx/tEPSYeEfPmg0dnTN /7umuPcg==; Received: from viro by zeniv.linux.org.uk with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1vHz3b-00000008ldY-07hj; Sun, 09 Nov 2025 06:37:47 +0000 From: Al Viro To: linux-fsdevel@vger.kernel.org Cc: torvalds@linux-foundation.org, brauner@kernel.org, jack@suse.cz, mjguzik@gmail.com, paul@paul-moore.com, axboe@kernel.dk, audit@vger.kernel.org, io-uring@vger.kernel.org Subject: [RFC][PATCH 13/13] struct filename ->refcnt doesn't need to be atomic Date: Sun, 9 Nov 2025 06:37:45 +0000 Message-ID: <20251109063745.2089578-14-viro@zeniv.linux.org.uk> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20251109063745.2089578-1-viro@zeniv.linux.org.uk> References: <20251109063745.2089578-1-viro@zeniv.linux.org.uk> Precedence: bulk X-Mailing-List: io-uring@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: Al Viro ... or visible outside of audit, really. Note that references held in delayed_filename always have refcount 1, and from the moment of complete_getname() or equivalent point in getname...() there is no references to struct filename instance anywhere that would be visible to other threads. Signed-off-by: Al Viro --- fs/namei.c | 8 ++++---- include/linux/fs.h | 8 +------- kernel/auditsc.c | 6 ++++++ 3 files changed, 11 insertions(+), 11 deletions(-) diff --git a/fs/namei.c b/fs/namei.c index bb306177b8a3..9863cc319181 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -128,7 +128,7 @@ static inline void initname(struct filename *name) { name->aname = NULL; - atomic_set(&name->refcnt, 1); + name->refcnt = 1; } static struct filename * @@ -283,13 +283,13 @@ void putname(struct filename *name) if (IS_ERR_OR_NULL(name)) return; - refcnt = atomic_read(&name->refcnt); + refcnt = name->refcnt; if (unlikely(refcnt != 1)) { if (WARN_ON_ONCE(!refcnt)) return; - if (!atomic_dec_and_test(&name->refcnt)) - return; + name->refcnt--; + return; } if (unlikely(name->name != name->iname)) { diff --git a/include/linux/fs.h b/include/linux/fs.h index d57c8e21be13..4ea32aba847b 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -2835,7 +2835,7 @@ extern struct kobject *fs_kobj; struct audit_names; struct filename { const char *name; /* pointer to actual string */ - atomic_t refcnt; + int refcnt; struct audit_names *aname; const char iname[]; }; @@ -2944,12 +2944,6 @@ int delayed_getname_uflags(struct delayed_filename *v, const char __user *, int) void dismiss_delayed_filename(struct delayed_filename *); struct filename *complete_getname(struct delayed_filename *); -static inline struct filename *refname(struct filename *name) -{ - atomic_inc(&name->refcnt); - return name; -} - extern int finish_open(struct file *file, struct dentry *dentry, int (*open)(struct inode *, struct file *)); extern int finish_no_open(struct file *file, struct dentry *dentry); diff --git a/kernel/auditsc.c b/kernel/auditsc.c index e59a094bb9f7..d71fc73455b2 100644 --- a/kernel/auditsc.c +++ b/kernel/auditsc.c @@ -2169,6 +2169,12 @@ static struct audit_names *audit_alloc_name(struct audit_context *context, return aname; } +static inline struct filename *refname(struct filename *name) +{ + name->refcnt++; + return name; +} + /** * __audit_getname - add a name to the list * @name: name to add -- 2.47.3