From patchwork Fri Sep 13 21:46:52 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jacopo Mondi X-Patchwork-Id: 13804116 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) (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 6B3DB1494DC for ; Fri, 13 Sep 2024 21:47:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=213.167.242.64 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726264047; cv=none; b=XvDTaacdK2H1lZRzJ104qrQc8odXcy6+Y/LIgB0wlQ87BNxMT/xAdaIpbqdHrQ5J/Qt46XmOpkj1jLKRT3rafIlBIU8e311mfAB2EClpipklfHZyMh6rGbx1ket3vf25U7p+KsPoNU3hFQvzkLwonMcleUs731m7dxTYM4G1kgI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726264047; c=relaxed/simple; bh=xxUPyC7ZR+OTUVsrPaK7+U/zRU0HEWUUqm07wIEEjSo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=fv3Omovj6i1Sj1G3ylpE6NB6FrEZICGgzSEZys5/HHS44tFnofqJJ/OiK3qT0Dfi9oyb2IfPJeKcka9NPf2VFwgowdX5WtVRJISKMlanBzuVXYyyYPKH81vMLKHz5CJqF08b9ArtCORBA9+V0iZirdhSnAsRh7tO8pxTmE6y7nM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=ideasonboard.com; spf=pass smtp.mailfrom=ideasonboard.com; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b=RyKLiwd3; arc=none smtp.client-ip=213.167.242.64 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="RyKLiwd3" Received: from ideasonboard.com (213-229-8-243.static.upcbusiness.at [213.229.8.243]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 770221BC7; Fri, 13 Sep 2024 23:45:50 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1726263950; bh=xxUPyC7ZR+OTUVsrPaK7+U/zRU0HEWUUqm07wIEEjSo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RyKLiwd3Qplthlnz9Gqc3QcrJsk2BFKSUQ9WIQvqWzIMFqqASVupUkhDdhE8OMG6t ReQaafKK8LNSyCl6YqE/DSp1UQZPhQuyIKGY7eiwtOjGq6gCd71NzX/OlFW5TEKhig rMbA7I558dPpkiUcV8DairPSqlNaElATtOAvWG68= From: Jacopo Mondi To: linux-media@vger.kernel.org Cc: Jacopo Mondi , Laurent Pinchart Subject: [PATCH 07/10] media: v4l2-dev: Add video_device_context_from_queue() Date: Fri, 13 Sep 2024 23:46:52 +0200 Message-ID: <20240913214657.1502838-8-jacopo.mondi@ideasonboard.com> X-Mailer: git-send-email 2.46.0 In-Reply-To: <20240913214657.1502838-1-jacopo.mondi@ideasonboard.com> References: <20240913214657.1502838-1-jacopo.mondi@ideasonboard.com> Precedence: bulk X-Mailing-List: linux-media@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Introduce an helper function to get a video_device_context from a videobuf2 queue. Device drivers that support multi-context operations will receive in their vb2_ops callbacks implementation a vb2_queue argument that is embedded in a video device context, either a context created by binding the video device to a media device context or the video device default context. This helper allows those drivers to retrieve the context the vb2_queue is embedded with. As the intended callers of this helpers are vb2_ops callbacks implementation, called by the videobuf2 core in response to an operation on a file handle, the returned context is guaranteed to be valid for the whole duration of the callback. Signed-off-by: Jacopo Mondi --- include/media/v4l2-dev.h | 36 ++++++++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+) diff --git a/include/media/v4l2-dev.h b/include/media/v4l2-dev.h index 32e61f9f9cb5..2ef49d0aaf09 100644 --- a/include/media/v4l2-dev.h +++ b/include/media/v4l2-dev.h @@ -796,6 +796,42 @@ void video_device_cleanup_context(struct video_device_context *ctx); struct video_device_context * video_device_context_from_file(struct file *filp, struct video_device *vdev); +/** + * video_device_context_from_queue - Get a video device context associated with + * a vb2 queue + * + * @q: the videobuf2 queue + * + * Return the video device context this videobuf2 queue belongs to. + * + * Device drivers that support multi-context operations will always be provided + * with a device context to work with, either a context created by userspace + * by binding the video device to a media device context or the video device + * default context. The videobuf2 queue that context-aware drivers operates will + * always be contained in either one of those contexts. + * + * This function should be used by driver-specific callbacks implementation of + * the vb2_ops which receive a videobuf2 as argument. Being the vb2_ops callback + * called by the videobuf2 core in response to a userspace operation on an open + * file handle, callers of this function are guaranteed to always receive a + * valid context reference by this function. The reference will remain valid for + * the whole function scope of the vb2_ops callback that has received the + * videobuf2 queue as argument. Likewise, accessing the media device context + * from the video device context returned by this function is always safe within + * the same function scope. + * + * Drivers that do not support multi-context operations shall never use + * this function. + * + * This function does not increase the reference count of the returned video + * device context. + */ +static inline struct video_device_context * +video_device_context_from_queue(struct vb2_queue *q) +{ + return container_of(q, struct video_device_context, queue); +} + #endif /* CONFIG_MEDIA_CONTROLLER */ #endif /* _V4L2_DEV_H */