From patchwork Mon Nov 6 12:25:19 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sakari Ailus X-Patchwork-Id: 741658 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 649D0C4167D for ; Mon, 6 Nov 2023 12:26:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231713AbjKFM0H (ORCPT ); Mon, 6 Nov 2023 07:26:07 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46318 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231723AbjKFM0G (ORCPT ); Mon, 6 Nov 2023 07:26:06 -0500 Received: from mgamail.intel.com (mgamail.intel.com [134.134.136.100]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1685DAB for ; Mon, 6 Nov 2023 04:26:03 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1699273563; x=1730809563; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=tdC4QW3xh6TgXx+kLdA+le4DwuNf1JSa7t5USSnbaoM=; b=OPKsZPdDDWfvf9mhrTrr1/tMs2DZxK/pxTnJI42mAV+Bt4FFr4KaeR2Y xUPAZmoMZFesSPZ89PQCtnpPb2wYAWtQHrE6UcL6gPmpu05PfcJJ4kBxt EGIhbKt3b1J1N1MCbTfQU9cZLeheTEunB3RnoFlAVXLguhI9X68ePgxeu fzGNWXLYtz6/i3b0gEcXEm0HHrKVhHHfmAKtDoyBrHz2aZxuZ1dZ2UFpb SFdw1PR2Q8U26pTiEs70BXo4rw2fLp8zvkf4F51fxWCpkM9wB5fng1Aqi mnnK+UwQ/e9s39qpApOvyPE3xAYcAhBkQDQThwwF9JYRtXTD9IgbvkAT3 A==; X-IronPort-AV: E=McAfee;i="6600,9927,10885"; a="455747262" X-IronPort-AV: E=Sophos;i="6.03,281,1694761200"; d="scan'208";a="455747262" Received: from orsmga001.jf.intel.com ([10.7.209.18]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 Nov 2023 04:26:02 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10885"; a="797291609" X-IronPort-AV: E=Sophos;i="6.03,281,1694761200"; d="scan'208";a="797291609" Received: from turnipsi.fi.intel.com (HELO kekkonen.fi.intel.com) ([10.237.72.44]) by orsmga001-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 Nov 2023 04:25:59 -0800 Received: from svinhufvud.ger.corp.intel.com (localhost [IPv6:::1]) by kekkonen.fi.intel.com (Postfix) with ESMTP id 4906411FB8D; Mon, 6 Nov 2023 14:25:56 +0200 (EET) From: Sakari Ailus To: linux-media@vger.kernel.org Cc: Laurent Pinchart , tomi.valkeinen@ideasonboard.com, bingbu.cao@intel.com, hongju.wang@intel.com, hverkuil@xs4all.nl, Andrey Konovalov , Jacopo Mondi , Dmitry Perchanov , "Ng, Khai Wen" , Alain Volmat Subject: [PATCH v7 11/31] media: v4l: subdev: Add a function to lock two sub-device states, use it Date: Mon, 6 Nov 2023 14:25:19 +0200 Message-Id: <20231106122539.1268265-12-sakari.ailus@linux.intel.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20231106122539.1268265-1-sakari.ailus@linux.intel.com> References: <20231106122539.1268265-1-sakari.ailus@linux.intel.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org Add two new functions, v4l2_subdev_lock_states() and v4l2_subdev_unclock_states(), to acquire and release the state of two sub-devices. They differ from calling v4l2_subdev_{un,}lock_state() so that if the two states share the same lock, the lock is acquired only once. Also use the new functions in v4l2_subdev_link_validate(). Signed-off-by: Sakari Ailus --- drivers/media/v4l2-core/v4l2-subdev.c | 12 +++----- include/media/v4l2-subdev.h | 40 +++++++++++++++++++++++++++ 2 files changed, 44 insertions(+), 8 deletions(-) diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c index 923a221955a9..cbc4d68f01c1 100644 --- a/drivers/media/v4l2-core/v4l2-subdev.c +++ b/drivers/media/v4l2-core/v4l2-subdev.c @@ -1377,17 +1377,13 @@ int v4l2_subdev_link_validate(struct media_link *link) states_locked = sink_state && source_state; - if (states_locked) { - v4l2_subdev_lock_state(sink_state); - v4l2_subdev_lock_state(source_state); - } + if (states_locked) + v4l2_subdev_lock_states(sink_state, source_state); ret = v4l2_subdev_link_validate_locked(link, states_locked); - if (states_locked) { - v4l2_subdev_unlock_state(sink_state); - v4l2_subdev_unlock_state(source_state); - } + if (states_locked) + v4l2_subdev_unlock_states(sink_state, source_state); return ret; } diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h index 34ef5f263bfb..24089543719c 100644 --- a/include/media/v4l2-subdev.h +++ b/include/media/v4l2-subdev.h @@ -1341,6 +1341,46 @@ static inline void v4l2_subdev_unlock_state(struct v4l2_subdev_state *state) mutex_unlock(state->lock); } +/** + * v4l2_subdev_lock_states - Lock two sub-device states + * @state1: One subdevice state + * @state2: The other subdevice state + * + * Locks the state of two sub-devices. + * + * The states must be unlocked with v4l2_subdev_unlock_states() after use. + * + * This differs from calling v4l2_subdev_lock_state() on both states so that if + * the states share the same lock, the lock is acquired only once (so no + * deadlock occurs). The caller is responsible for ensuring the locks will + * always be acquired in the same order. + */ +static inline void v4l2_subdev_lock_states(struct v4l2_subdev_state *state1, + struct v4l2_subdev_state *state2) +{ + mutex_lock(state1->lock); + if (state1->lock != state2->lock) + mutex_lock(state2->lock); +} + +/** + * v4l2_subdev_unlock_states() - Unlock two sub-device states + * @state1: One subdevice state + * @state2: The other subdevice state + * + * Unlocks the state of two sub-devices. + * + * This differs from calling v4l2_subdev_unlock_state() on both states so that + * if the states share the same lock, the lock is released only once. + */ +static inline void v4l2_subdev_unlock_states(struct v4l2_subdev_state *state1, + struct v4l2_subdev_state *state2) +{ + mutex_unlock(state1->lock); + if (state1->lock != state2->lock) + mutex_unlock(state2->lock); +} + /** * v4l2_subdev_get_unlocked_active_state() - Checks that the active subdev state * is unlocked and returns it