From nobody Fri Sep 25 13:55:24 2026 Received: from m16.mail.163.com (m16.mail.163.com [220.197.31.2]) (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 20C993939B5 for ; Fri, 11 Sep 2026 16:08:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=220.197.31.2 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789142892; cv=none; b=RLjhZqfPR1cQjYB5sw8amRZJvbf1+g5RYvcxnIPvpgBN+0AQ4jmSTf5YSLt+St+fzVrshJFCay5+hEo/HRrcz6xX7s0GO2ejDRitWZOw8kBtMEMmDHG5wcujBR/zb2fP2HS5qIz4FY+rAdpHh2ovgU/tZ3uIgLaW4GsjlFh1rEQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789142892; c=relaxed/simple; bh=Qk8yNt3dIw9MmiYHBJfZI8dXlL65XA8tjJbeaLoEjKw=; h=Date:From:To:Cc:Subject:Message-ID:MIME-Version:Content-Type: Content-Disposition; b=de+6Py0qNPkPlR4m1Nr7iu3fYw45eKFM3TNV9Gf2wiJueylxT9/WFTWyIkXzg1ZJ0TWNK6zkRFGUCUxlIbVVjafDKDy52Q9hqhyOUmLtuIsvKFnxzQa0ypN4jwu1HAM/cp3pQuBe3CNvhi4wkCRHAsCxGzEbjimkaSyCkQggYC8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com; spf=pass smtp.mailfrom=163.com; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b=ZkKLvWwh; arc=none smtp.client-ip=220.197.31.2 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=163.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b="ZkKLvWwh" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=Date:From:To:Subject:Message-ID:MIME-Version: Content-Type; bh=MfL9H/fohvo4ifqEg/LeDNsotyf7q1p0FbmL7Ufgp78=; b=ZkKLvWwhcmHInno6dlbPvWHVyGP5WEii4Mxq1bHeWtUxcye9bKsJdvdnF2tH8f RCmkAw/k47IqZobLi8njrrjXe4IOhZ6arssdXFEGb/cPU/VN4zDaZAWayROWol8z 3D+OH+s9QtKXEZnHV/kVlvI/HssrO408OSv1z3AkdP8fw= Received: from localhost (unknown []) by gzsmtp1 (Coremail) with SMTP id PCgvCgA36GFFJ6RqZNzfOg--.56920S2; Sat, 12 Sep 2026 00:07:33 +0800 (CST) Date: Sat, 12 Sep 2026 00:07:33 +0800 From: Hao Zhang To: dm-devel@lists.linux.dev Cc: agk@redhat.com, snitzer@kernel.org, mpatocka@redhat.com, bmarzins@redhat.com, linux-kernel@vger.kernel.org Subject: [PATCH] dm thin: Remove unnecessary locking from pool_map() Message-ID: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Disposition: inline X-CM-TRANSID: PCgvCgA36GFFJ6RqZNzfOg--.56920S2 X-Coremail-Antispam: 1Uf129KBjvJXoW7CF1fGF13KFy3XFyxXr4Utwb_yoW8Jw4UpF ZFga9xZ34UWrW2gF1DX3yv9F45X3ZYg3y2kry7Ga4Sqrn5WFyfZFy7tFWavF9YgF9xGryY vFWjyr98ZF45t3DanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x07j0g4fUUUUU= X-CM-SenderInfo: pkdrs65kdqwshngh4qqrwthudrp/xtbC3QWekWqkJ0XYmQAA36 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Hao Zhang pool_map() takes pool->lock only while setting the bio's data device. The pool target's data_dev is initialized when the target is constructed and is not changed afterwards. The device-mapper target remains alive while its map callback is running, so pool->lock is not needed to protect data_dev. Remove the unnecessary locking. This also avoids holding pool->lock across bio_set_dev(), which may perform a blkcg lookup and acquire the request queue's queue_lock. Signed-off-by: Hao Zhang --- drivers/md/dm-thin.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c index 59392de7a477..358ed77ffb2b 100644 --- a/drivers/md/dm-thin.c +++ b/drivers/md/dm-thin.c @@ -3438,14 +3438,11 @@ static int pool_ctr(struct dm_target *ti, unsigned = int argc, char **argv) static int pool_map(struct dm_target *ti, struct bio *bio) { struct pool_c *pt =3D ti->private; - struct pool *pool =3D pt->pool; =20 /* * As this is a singleton target, ti->begin is always zero. */ - spin_lock_irq(&pool->lock); bio_set_dev(bio, pt->data_dev->bdev); - spin_unlock_irq(&pool->lock); =20 return DM_MAPIO_REMAPPED; } base-commit: 08df884136f1c1197bab2a27814404fd329d9aac --=20 2.15.0