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Feb 2025 15:43:27 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: [PATCH 2/2] configfs: Add mechanism to prevent item/group deletion To: =?utf-8?b?Sm9zw6kgRXhww7NzaXRv?= Cc: hamohammed.sa@gmail.com, simona@ffwll.ch, melissa.srw@gmail.com, maarten.lankhorst@linux.intel.com, mripard@kernel.org, tzimmermann@suse.de, airlied@gmail.com, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org References: <20250225175936.7223-1-jose.exposito89@gmail.com> <20250225175936.7223-4-jose.exposito89@gmail.com> Content-Language: en-US From: Louis Chauvet Autocrypt: addr=louis.chauvet@bootlin.com; keydata= xsFNBGCG5KEBEAD1yQ5C7eS4rxD0Wj7JRYZ07UhWTbBpbSjHjYJQWx/qupQdzzxe6sdrxYSY 5K81kIWbtQX91pD/wH5UapRF4kwMXTAqof8+m3XfYcEDVG31Kf8QkJTG/gLBi1UfJgGBahbY hjP40kuUR/mr7M7bKoBP9Uh0uaEM+DuKl6bSXMSrJ6fOtEPOtnfBY0xVPmqIKfLFEkjh800v jD1fdwWKtAIXf+cQtC9QWvcdzAmQIwmyFBmbg+ccqao1OIXTgu+qMAHfgKDjYctESvo+Szmb DFBZudPbyTAlf2mVKpoHKMGy3ndPZ19RboKUP0wjrF+Snif6zRFisHK7D/mqpgUftoV4HjEH 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CIegqm2Av1939XXGZJVI9f3hEoUn04rvxCgcDcUvn7I0WTZ4JB9G5qAGvQLXeXK6Byu77qTx eC7PUIIEKN3X47e8xTSj2reVTlanDr8yeqZhxpKHaS0laF8RbD85geZtAK67qEByX2KC9DUo eHBFuXpYMzGQnf2SG105ePI2f4h5iAfbTW9VWH989fx4f2hVlDwTe08/NhPdwq/Houov9f/+ uPpYEMlHCNwE8GRV7aEjd/dvu87PQPm4zFtC3jgQaUKCbYYlHmYYRlrLQenX3QSorrQNPbfz uQkNLDVcjgD2fxBpemT7EhHYBz+ugsfbtdsH+4jVCo5WLb/HxE6o5zvSIkXknWh1DhFj/qe9 Zb9PGmfp8T8Ty+c/hjE5x6SrkRCX8qPXIvfSWLlb8M0lpcpFK+tB+kZlu5I3ycQDNLTk3qmf PdjUMWb5Ld21PSyCrtGc/hTKwxMoHsOZPy6UB8YJ5omZdsavcjKMrDpybguOfxUmGYs2H3MJ ghIUQMMOe0267uQcmMNDPRueGWTLXcuyz0Tpe62Whekc3gNMl0JrNz6Gty8OBb/ETijfSHPE qGHYuyAZJo9A/IazHuJ+4n+gm4kQl1WLfxoRMzYHCA== In-Reply-To: <20250225175936.7223-4-jose.exposito89@gmail.com> X-GND-State: clean X-GND-Score: -100 X-GND-Cause: gggruggvucftvghtrhhoucdtuddrgeefvddrtddtgdeltdeiiecutefuodetggdotefrodftvfcurfhrohhfihhlvgemucfitefpfffkpdcuggftfghnshhusghstghrihgsvgenuceurghilhhouhhtmecufedtudenucesvcftvggtihhpihgvnhhtshculddquddttddmnecujfgurhepkfffgggfuffvvehfhfgjtgfgsehtjeertddtvdejnecuhfhrohhmpefnohhuihhsucevhhgruhhvvghtuceolhhouhhishdrtghhrghuvhgvthessghoohhtlhhinhdrtghomheqnecuggftrfgrthhtvghrnhepgfffveeuudeuhfekteeuhefhhedtleejgeehheduheeigfejteetueeifeehveevnecukfhppeeltddrkeelrdduieefrdduvdejnecuvehluhhsthgvrhfuihiivgeptdenucfrrghrrghmpehinhgvthepledtrdekledrudeifedruddvjedphhgvlhhopegludelvddrudeikedrtddrvddtngdpmhgrihhlfhhrohhmpehlohhuihhsrdgthhgruhhvvghtsegsohhothhlihhnrdgtohhmpdhnsggprhgtphhtthhopedutddprhgtphhtthhopehjohhsvgdrvgigphhoshhithhokeelsehgmhgrihhlrdgtohhmpdhrtghpthhtohephhgrmhhohhgrmhhmvggurdhsrgesghhmrghilhdrtghomhdprhgtphhtthhopehsihhmohhnrgesfhhffihllhdrtghhpdhrtghpthhtohepmhgvlhhishhsrgdrshhrfiesghhmrghilhdrtghomhdprhgtphhtthhopehmrggrrhhtvghnrdhlrghnkhhhohhrshhtsehlihhnu higrdhinhhtvghlrdgtohhmpdhrtghpthhtohepmhhrihhprghrugeskhgvrhhnvghlrdhorhhgpdhrtghpthhtohepthiiihhmmhgvrhhmrghnnhesshhushgvrdguvgdprhgtphhtthhopegrihhrlhhivggusehgmhgrihhlrdgtohhm X-GND-Sasl: louis.chauvet@bootlin.com X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Introduce a new mechanism in configfs to prevent the deletion of certain item/group. This is particularly useful in scenarios where userspace should not be allowed to modify the configfs structure under some conditions, such as in VKMS. Signed-off-by: Louis Chauvet --- drivers/gpu/drm/vkms/vkms_configfs.c | 21 +++++++++++++++++++++ fs/configfs/dir.c | 8 +++++++- include/linux/configfs.h | 1 + 3 files changed, 29 insertions(+), 1 deletion(-) *item); void (*drop_item)(struct config_group *group, struct config_item *item); bool (*is_visible)(struct config_item *item, struct configfs_attribute *attr, int n); bool (*is_bin_visible)(struct config_item *item, struct configfs_bin_attribute *attr, diff --git a/drivers/gpu/drm/vkms/vkms_configfs.c b/drivers/gpu/drm/vkms/vkms_configfs.c index 8a7d954399e9..0a196a28ed4a 100644 --- a/drivers/gpu/drm/vkms/vkms_configfs.c +++ b/drivers/gpu/drm/vkms/vkms_configfs.c @@ -393,9 +393,30 @@ static struct configfs_item_operations plane_item_operations = { .release = &plane_release, }; +int allow_drop_plane_group(struct config_group *group, struct config_item *item) +{ + struct vkms_configfs_plane *plane; + bool enabled; + + plane = plane_item_to_vkms_configfs_plane(item); + + mutex_lock(&plane->dev->lock); + enabled = plane->dev->enabled; + mutex_unlock(&plane->dev->lock); + + if (enabled) + return -EBUSY; + return 0; +} + +static struct configfs_group_operations plane_group_operation ={ + .allow_drop_item = &allow_drop_plane_group, +}; + static const struct config_item_type plane_item_type = { .ct_attrs = plane_item_attrs, .ct_item_ops = &plane_item_operations, + .ct_group_ops = &plane_group_operation, .ct_owner = THIS_MODULE, }; diff --git a/fs/configfs/dir.c b/fs/configfs/dir.c index 7d10278db30d..a103196af0f9 100644 --- a/fs/configfs/dir.c +++ b/fs/configfs/dir.c @@ -1544,7 +1544,13 @@ static int configfs_rmdir(struct inode *dir, struct dentry *dentry) /* Drop reference from above, item already holds one. */ config_item_put(parent_item); - + if (item->ci_type && item->ci_type->ct_group_ops && item->ci_type->ct_group_ops->allow_drop_item) { + ret = item->ci_type->ct_group_ops->allow_drop_item(to_config_group(parent_item), item); + if (ret) { + config_item_put(item); + return ret; + } + } if (item->ci_type) dead_item_owner = item->ci_type->ct_owner; diff --git a/include/linux/configfs.h b/include/linux/configfs.h index 7fc52a78d6cd..92933397590d 100644 --- a/include/linux/configfs.h +++ b/include/linux/configfs.h @@ -216,6 +216,7 @@ struct configfs_group_operations { struct config_item *(*make_item)(struct config_group *group, const char *name); struct config_group *(*make_group)(struct config_group *group, const char *name); void (*disconnect_notify)(struct config_group *group, struct config_item *item); + int (*allow_drop_item)(struct config_group *group, struct config_item