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{
    "id": 20993,
    "url": "https://patchwork.libcamera.org/api/1.1/patches/20993/?format=api",
    "web_url": "https://patchwork.libcamera.org/patch/20993/",
    "project": {
        "id": 1,
        "url": "https://patchwork.libcamera.org/api/1.1/projects/1/?format=api",
        "name": "libcamera",
        "link_name": "libcamera",
        "list_id": "libcamera_core",
        "list_email": "libcamera-devel@lists.libcamera.org",
        "web_url": "",
        "scm_url": "",
        "webscm_url": ""
    },
    "msgid": "<20240822153527.25320-5-laurent.pinchart+renesas@ideasonboard.com>",
    "date": "2024-08-22T15:35:24",
    "name": "[v2,4/7] media: v4l2-subdev: Refactor warnings in v4l2_subdev_link_validate()",
    "commit_ref": null,
    "pull_url": null,
    "state": "not-applicable",
    "archived": false,
    "hash": "68982c452864bbd0a2d1d5dd7d8110a56b3a679f",
    "submitter": {
        "id": 204,
        "url": "https://patchwork.libcamera.org/api/1.1/people/204/?format=api",
        "name": "Laurent Pinchart",
        "email": "laurent.pinchart+renesas@ideasonboard.com"
    },
    "delegate": null,
    "mbox": "https://patchwork.libcamera.org/patch/20993/mbox/",
    "series": [
        {
            "id": 4533,
            "url": "https://patchwork.libcamera.org/api/1.1/series/4533/?format=api",
            "web_url": "https://patchwork.libcamera.org/project/libcamera/list/?series=4533",
            "date": "2024-08-22T15:35:20",
            "name": "media: v4l2: Improve media link validation",
            "version": 2,
            "mbox": "https://patchwork.libcamera.org/series/4533/mbox/"
        }
    ],
    "comments": "https://patchwork.libcamera.org/api/patches/20993/comments/",
    "check": "pending",
    "checks": "https://patchwork.libcamera.org/api/patches/20993/checks/",
    "tags": {},
    "headers": {
        "Return-Path": "<libcamera-devel-bounces@lists.libcamera.org>",
        "X-Original-To": "parsemail@patchwork.libcamera.org",
        "Delivered-To": "parsemail@patchwork.libcamera.org",
        "Received": [
            "from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id B1B44C323E\n\tfor <parsemail@patchwork.libcamera.org>;\n\tThu, 22 Aug 2024 15:35:43 +0000 (UTC)",
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        ],
        "Authentication-Results": "lancelot.ideasonboard.com; dkim=pass (1024-bit key;\n\tunprotected) header.d=ideasonboard.com header.i=@ideasonboard.com\n\theader.b=\"ZO+znxHn\"; dkim-atps=neutral",
        "DKIM-Signature": "v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1724340872;\n\tbh=L6PW/jnfXa4+nyLEP2SbfgQft2F4O8LsNw4OqltCe/g=;\n\th=From:To:Cc:Subject:Date:In-Reply-To:References:From;\n\tb=ZO+znxHn3QUDNjcqbTqpq5ynt1/dPTE2hJtRe/CxAqN3qTvmEwQOdWsZBUcucydF2\n\tzwQ90wAJuGORKewyOgycAP7hT2SqYnLS6qLd08JcWiMHip3QwfkO30trLNUHD7FUgC\n\tKOC5ntjV3Uq7n6yQcih78sejBZ7AzISFoIdO0lEA=",
        "From": "Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>",
        "To": "libcamera-devel@lists.libcamera.org",
        "Cc": "Chen-Yu Tsai <wens@csie.org>, Eugen Hristev <eugen.hristev@collabora.com>,\n\tHans Verkuil <hverkuil-cisco@xs4all.nl>,\n\tJacopo Mondi <jacopo.mondi@ideasonboard.com>,\n\tKieran Bingham <kieran.bingham@ideasonboard.com>,\n\tMaxime Ripard <mripard@kernel.org>, Sakari Ailus <sakari.ailus@iki.fi>,\n\tTomi Valkeinen <tomi.valkeinen@ideasonboard.com>,\n\tlinux-renesas-soc@vger.kernel.org, linux-sunxi@lists.linux.dev",
        "Subject": "[PATCH v2 4/7] media: v4l2-subdev: Refactor warnings in\n\tv4l2_subdev_link_validate()",
        "Date": "Thu, 22 Aug 2024 18:35:24 +0300",
        "Message-ID": "<20240822153527.25320-5-laurent.pinchart+renesas@ideasonboard.com>",
        "X-Mailer": "git-send-email 2.44.2",
        "In-Reply-To": "<20240822153527.25320-1-laurent.pinchart+renesas@ideasonboard.com>",
        "References": "<20240822153527.25320-1-laurent.pinchart+renesas@ideasonboard.com>",
        "MIME-Version": "1.0",
        "Content-Transfer-Encoding": "8bit",
        "X-BeenThere": "libcamera-devel@lists.libcamera.org",
        "X-Mailman-Version": "2.1.29",
        "Precedence": "list",
        "List-Id": "<libcamera-devel.lists.libcamera.org>",
        "List-Unsubscribe": "<https://lists.libcamera.org/options/libcamera-devel>,\n\t<mailto:libcamera-devel-request@lists.libcamera.org?subject=unsubscribe>",
        "List-Archive": "<https://lists.libcamera.org/pipermail/libcamera-devel/>",
        "List-Post": "<mailto:libcamera-devel@lists.libcamera.org>",
        "List-Help": "<mailto:libcamera-devel-request@lists.libcamera.org?subject=help>",
        "List-Subscribe": "<https://lists.libcamera.org/listinfo/libcamera-devel>,\n\t<mailto:libcamera-devel-request@lists.libcamera.org?subject=subscribe>",
        "Errors-To": "libcamera-devel-bounces@lists.libcamera.org",
        "Sender": "\"libcamera-devel\" <libcamera-devel-bounces@lists.libcamera.org>"
    },
    "content": "The v4l2_subdev_link_validate() function prints a one-time warning if it\ngets called on a link whose source or sink is not a subdev. As links get\nvalidated in the context of their sink, a call to the helper when the\nlink's sink is not a subdev indicates that the driver has set its\n.link_validate() handler to v4l2_subdev_link_validate() on a non-subdev\nentity, which is a clear driver bug. On the other hand, the link's\nsource not being a subdev indicates that the helper is used for a subdev\nconnected to a video output device, which is a lesser issue, if only\nbecause this is currently common practice.\n\nThere are no drivers left in the kernel that use\nv4l2_subdev_link_validate() in a context where it may get called on a\nnon-subdev sink. Replace the pr_warn_once() with a WARN_ON_ONCE() in\nthis case to make sure that new offenders won't be introduced.\n\nSigned-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>\n---\nChanges since v1:\n\n- Switch from WARN_ON() to WARN_ON_ONCE()\n---\n drivers/media/v4l2-core/v4l2-subdev.c | 14 +++++++++-----\n 1 file changed, 9 insertions(+), 5 deletions(-)",
    "diff": "diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c\nindex 7c5812d55315..d3196042d5c5 100644\n--- a/drivers/media/v4l2-core/v4l2-subdev.c\n+++ b/drivers/media/v4l2-core/v4l2-subdev.c\n@@ -1443,11 +1443,15 @@ int v4l2_subdev_link_validate(struct media_link *link)\n \tbool states_locked;\n \tint ret;\n \n-\tif (!is_media_entity_v4l2_subdev(link->sink->entity) ||\n-\t    !is_media_entity_v4l2_subdev(link->source->entity)) {\n-\t\tpr_warn_once(\"%s of link '%s':%u->'%s':%u is not a V4L2 sub-device, driver bug!\\n\",\n-\t\t\t     !is_media_entity_v4l2_subdev(link->sink->entity) ?\n-\t\t\t     \"sink\" : \"source\",\n+\t/*\n+\t * Links are validated in the context of the sink entity. Usage of this\n+\t * helper on a sink that is not a subdev is a clear driver bug.\n+\t */\n+\tif (WARN_ON_ONCE(!is_media_entity_v4l2_subdev(link->sink->entity)))\n+\t\treturn -EINVAL;\n+\n+\tif (!is_media_entity_v4l2_subdev(link->source->entity)) {\n+\t\tpr_warn_once(\"source of link '%s':%u->'%s':%u is not a V4L2 sub-device, driver bug!\\n\",\n \t\t\t     link->source->entity->name, link->source->index,\n \t\t\t     link->sink->entity->name, link->sink->index);\n \t\treturn 0;\n",
    "prefixes": [
        "v2",
        "4/7"
    ]
}