From nobody Fri Dec 19 04:03:16 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9F58AC83F01 for ; Wed, 30 Aug 2023 18:53:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243616AbjH3StK (ORCPT ); Wed, 30 Aug 2023 14:49:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52128 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343952AbjH3Rfg (ORCPT ); Wed, 30 Aug 2023 13:35:36 -0400 Received: from rere.qmqm.pl (rere.qmqm.pl [91.227.64.183]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A3AEE1A2 for ; Wed, 30 Aug 2023 10:35:33 -0700 (PDT) Received: from remote.user (localhost [127.0.0.1]) by rere.qmqm.pl (Postfix) with ESMTPSA id 4RbWfD1bCTzVr; Wed, 30 Aug 2023 19:35:32 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=rere.qmqm.pl; s=1; t=1693416932; bh=d/uWZtIzyiyl8negxdWeJKWCN/bjWfnYvB5RCFJNH3Q=; h=Date:In-Reply-To:References:Subject:From:To:Cc:From; b=JTFHfML1EUtRxjdnL38X/yCPC/OfDVdKOiz7ON0u3Fdeu8GBs563VHAafNI1CYCLP CBUCp5neaGYtus2Wgf7mOmxWUoZyXJfNBB5C8nvTV4/LJmNGx5XQrZr3onS93a8Ccq NrHMCiPpp6/I7FzVu1cXkftiiS8Wcehr9RGSZfQvhi+UfykuXlNc4t7HvKxBj8qLJR 2ZjEV6ra98CTCJoPlreIonp/rB1sNYlRhbTzDqMcfW2fiL6/kjxkd0ruHkPx5nOLoK vJCf7F2XxjfTpB+sJUugvWKJuzSfXBKX0nKkgH+q/55NLdH4+6sFfoUmx/N8eyeZ1A TLgy4/T8guf8g== X-Virus-Status: Clean X-Virus-Scanned: clamav-milter 0.103.8 at mail Date: Wed, 30 Aug 2023 19:35:31 +0200 Message-Id: <56ae0bf828d942c92ca867afb3aae95fcabd5498.1693416477.git.mirq-linux@rere.qmqm.pl> In-Reply-To: References: Subject: [PATCH v2 3/7] regulator/core: regulator_lock_nested: simplify nested locking MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable From: =?UTF-8?q?Micha=C5=82=20Miros=C5=82aw?= To: Liam Girdwood , Mark Brown Cc: Douglas Anderson , linux-kernel@vger.kernel.org, Stephen Boyd Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Simplify regulator locking by removing locking around locking. rdev->ref check when unlocking is moved inside the critical section. This patch depends on commit 12235da8c80a ("kernel/locking: Add context to ww_mutex_trylock()"). Note: return -EALREADY is removed as no caller depends on it and in that case the lock count is incremented anyway. Reviewed-by: Douglas Anderson Signed-off-by: Micha=C5=82 Miros=C5=82aw --- drivers/regulator/core.c | 23 ++++++----------------- 1 file changed, 6 insertions(+), 17 deletions(-) diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c index 921c7039baa3..f18e7cb88a0d 100644 --- a/drivers/regulator/core.c +++ b/drivers/regulator/core.c @@ -34,7 +34,6 @@ #include "internal.h" =20 static DEFINE_WW_CLASS(regulator_ww_class); -static DEFINE_MUTEX(regulator_nesting_mutex); static DEFINE_MUTEX(regulator_list_mutex); static LIST_HEAD(regulator_map_list); static LIST_HEAD(regulator_ena_gpio_list); @@ -141,25 +140,18 @@ static bool regulator_ops_is_valid(struct regulator_d= ev *rdev, int ops) static inline int regulator_lock_nested(struct regulator_dev *rdev, struct ww_acquire_ctx *ww_ctx) { - int ret =3D 0; - - mutex_lock(®ulator_nesting_mutex); - if (!ww_mutex_trylock(&rdev->mutex, ww_ctx) && - rdev->mutex_owner !=3D current) { - mutex_unlock(®ulator_nesting_mutex); - ret =3D ww_mutex_lock(&rdev->mutex, ww_ctx); + READ_ONCE(rdev->mutex_owner) !=3D current) { + int ret =3D ww_mutex_lock(&rdev->mutex, ww_ctx); + if (ret =3D=3D -EDEADLK) return ret; - mutex_lock(®ulator_nesting_mutex); } =20 rdev->ref_cnt++; rdev->mutex_owner =3D current; =20 - mutex_unlock(®ulator_nesting_mutex); - - return ret; + return 0; } =20 /** @@ -186,16 +178,13 @@ static void regulator_lock(struct regulator_dev *rdev) */ static void regulator_unlock(struct regulator_dev *rdev) { - mutex_lock(®ulator_nesting_mutex); + if (WARN_ON_ONCE(rdev->ref_cnt <=3D 0)) + return; =20 if (--rdev->ref_cnt =3D=3D 0) { rdev->mutex_owner =3D NULL; ww_mutex_unlock(&rdev->mutex); } - - WARN_ON_ONCE(rdev->ref_cnt < 0); - - mutex_unlock(®ulator_nesting_mutex); } =20 /** --=20 2.39.2