From patchwork Tue Jun 14 19:10:48 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paul Elder X-Patchwork-Id: 12881402 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 86C91CCA47A for ; Tue, 14 Jun 2022 19:13:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1353089AbiFNTNA (ORCPT ); Tue, 14 Jun 2022 15:13:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52718 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1348261AbiFNTMz (ORCPT ); Tue, 14 Jun 2022 15:12:55 -0400 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 58E2E11C0F for ; Tue, 14 Jun 2022 12:12:54 -0700 (PDT) Received: from pyrite.rasen.tech (softbank036240126034.bbtec.net [36.240.126.34]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id D39CC825; Tue, 14 Jun 2022 21:12:49 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1655233973; bh=OTnYQuvlSCEpGxJsQky+B7kiN2Ypy9jL3LZYyc2briI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=CK5oen+KeOy3ybrgXRPXrGAYOZNbIo4OvJCLFOlXJeXppllcvk/57qnx8mKWaThna Pqy/51ShQoN07wIWX3YzwwbWPMETB9C8LHIxQJ4wNy1HcIM/LlGlym/tMuG8n4eDFm CPqG0la1MEYpkl9HFv3NGnxp4n8X4K+cqL4Y8nJY= From: Paul Elder To: linux-media@vger.kernel.org Cc: Laurent Pinchart , dafna@fastmail.com, heiko@sntech.de, jeanmichel.hautbois@ideasonboard.com, jacopo@jmondi.org, djrscally@gmail.com, helen.koike@collabora.com, linux-rockchip@lists.infradead.org Subject: [PATCH 16/55] media: v4l2-async: Add notifier operation to destroy asd instances Date: Wed, 15 Jun 2022 04:10:48 +0900 Message-Id: <20220614191127.3420492-17-paul.elder@ideasonboard.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220614191127.3420492-1-paul.elder@ideasonboard.com> References: <20220614191127.3420492-1-paul.elder@ideasonboard.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org From: Laurent Pinchart Drivers typically extend the v4l2_async_subdev structure by embedding it in a driver-specific structure, to store per-subdev custom data. The v4l2_async_subdev instances are freed by the v4l2-async framework, which makes this mechanism cumbersome to use safely when custom data needs special treatment to be destroyed (such as freeing additional memory, or releasing references to kernel objects). To ease this, add a .destroy() operation to the v4l2_async_notifier_operations structure. The operation is called right before the v4l2_async_subdev is freed, giving drivers a chance to destroy data if needed. Signed-off-by: Laurent Pinchart Reviewed-by: Hans Verkuil --- Documentation/driver-api/media/v4l2-subdev.rst | 6 ++++++ drivers/media/v4l2-core/v4l2-async.c | 10 ++++++++++ include/media/v4l2-async.h | 2 ++ 3 files changed, 18 insertions(+) diff --git a/Documentation/driver-api/media/v4l2-subdev.rst b/Documentation/driver-api/media/v4l2-subdev.rst index cf3b52bdbfb9..6f8d79926aa5 100644 --- a/Documentation/driver-api/media/v4l2-subdev.rst +++ b/Documentation/driver-api/media/v4l2-subdev.rst @@ -243,6 +243,12 @@ notifier callback is called. After all subdevices have been located the .complete() callback is called. When a subdevice is removed from the system the .unbind() method is called. All three callbacks are optional. +Drivers can store any type of custom data in their driver-specific +:c:type:`v4l2_async_subdev` wrapper. If any of that data requires special +handling when the structure is freed, drivers must implement the ``.destroy()`` +notifier callback. The framework will call it right before freeing the +:c:type:`v4l2_async_subdev`. + Calling subdev operations ~~~~~~~~~~~~~~~~~~~~~~~~~ diff --git a/drivers/media/v4l2-core/v4l2-async.c b/drivers/media/v4l2-core/v4l2-async.c index c6995718237a..735dede624b8 100644 --- a/drivers/media/v4l2-core/v4l2-async.c +++ b/drivers/media/v4l2-core/v4l2-async.c @@ -52,6 +52,15 @@ static int v4l2_async_nf_call_complete(struct v4l2_async_notifier *n) return n->ops->complete(n); } +static void v4l2_async_nf_call_destroy(struct v4l2_async_notifier *n, + struct v4l2_async_subdev *asd) +{ + if (!n->ops || !n->ops->destroy) + return; + + n->ops->destroy(asd); +} + static bool match_i2c(struct v4l2_async_notifier *notifier, struct v4l2_subdev *sd, struct v4l2_async_subdev *asd) { @@ -626,6 +635,7 @@ static void __v4l2_async_nf_cleanup(struct v4l2_async_notifier *notifier) } list_del(&asd->asd_list); + v4l2_async_nf_call_destroy(notifier, asd); kfree(asd); } } diff --git a/include/media/v4l2-async.h b/include/media/v4l2-async.h index 13ff3ad948f4..25eb1d138c06 100644 --- a/include/media/v4l2-async.h +++ b/include/media/v4l2-async.h @@ -81,6 +81,7 @@ struct v4l2_async_subdev { * @complete: All subdevices have been probed successfully. The complete * callback is only executed for the root notifier. * @unbind: a subdevice is leaving + * @destroy: the asd is about to be freed */ struct v4l2_async_notifier_operations { int (*bound)(struct v4l2_async_notifier *notifier, @@ -90,6 +91,7 @@ struct v4l2_async_notifier_operations { void (*unbind)(struct v4l2_async_notifier *notifier, struct v4l2_subdev *subdev, struct v4l2_async_subdev *asd); + void (*destroy)(struct v4l2_async_subdev *asd); }; /**