Merge tag 'configfs-7.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/leitao/linux

d4d9eb22 · Linus Torvalds <[email protected]> · 2026-10-20 16:25:43 -10:00

Pull configfs updates from Breno Leitao:

 - Attribute structures can now be const (Thomas Weißschuh)

 - The first selftests for the configfs userspace interface, plus a
   sample subsystem that accepts symlinks to test against. They include
   a race of symlink(2) against rmdir of the target, which exercises the
   use-after-free fixed in v7.3-rc3.

 - Rust bindings, merged from Andreas Hindborg's signed tag: fix the
   data offset calculation in subsystem callbacks (marked for stable),
   add the missing Send and Sync bounds, and correct a safety comment.

* tag 'configfs-7.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/leitao/linux:
  samples: configfs: constify the configfs_attribute structures
  configfs: Allow the registration of const struct configfs_attribute
  configfs: Constify configfs_bin_attribute
  configfs: Treat attribute structures as const internally
  configfs: Constify is_visible/is_visible_bin in configfs_group_operations
  rust: configfs: remove mutability from some field initializers
  selftests/configfs: race symlink against rmdir of the target
  selftests/configfs: cover symlink and unlink
  samples/configfs: add a subsystem that accepts symlinks
  selftests/configfs: add tests for the userspace interface
  rust: configfs: fix data offset calculation for subsystem callbacks
  rust: configfs: require thread-safe callback data
  rust: configfs: fix release safety documentation

Commit: d4d9eb226e4c2af8ab390bb470477fa68072fa2a
Parents: 32543b09 · 6c1fa55e

Merge commit. Changes below are compared with the first parent: 32543b09.

Changes

16 files changed · +771 −107

File	Status	Add	Del	Content
MAINTAINERS	modified	+1	−0	View file
drivers/acpi/acpi_configfs.c	modified	+1	−1	View file
drivers/gpu/drm/xe/xe_configfs.c	modified	+2	−2	View file
drivers/virt/coco/guest/report.c	modified	+3	−3	View file
fs/configfs/configfs_internal.h	modified	+5	−5	View file
fs/configfs/dir.c	modified	+5	−5	View file
fs/configfs/file.c	modified	+3	−3	View file
fs/configfs/inode.c	modified	+1	−1	View file
include/linux/configfs.h	modified	+38	−35	View file
rust/kernel/configfs.rs	modified	+86	−44	View file
samples/configfs/configfs_sample.c	modified	+129	−8	View file
tools/testing/selftests/Makefile	modified	+1	−0	View file
tools/testing/selftests/filesystems/configfs/.gitignore	added	+2	−0	View file
tools/testing/selftests/filesystems/configfs/Makefile	added	+8	−0	View file
tools/testing/selftests/filesystems/configfs/config	added	+5	−0	View file
tools/testing/selftests/filesystems/configfs/configfs_test.c	added	+481	−0	View file

Only the first 600 diff lines are shown. Download the complete patch.

MAINTAINERS

View file

diff --git a/MAINTAINERS b/MAINTAINERS
index 7895e77..63a8878 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -6603,6 +6603,7 @@ S:	Supported
 F:	fs/configfs/
 F:	include/linux/configfs.h
 F:	samples/configfs/
+F:	tools/testing/selftests/filesystems/configfs/
 
 CONFIGFS [RUST]
 M:	Andreas Hindborg <[email protected]>

drivers/acpi/acpi_configfs.c

View file

diff --git a/drivers/acpi/acpi_configfs.c b/drivers/acpi/acpi_configfs.c
index 12ffec7..6071699 100644
--- a/drivers/acpi/acpi_configfs.c
+++ b/drivers/acpi/acpi_configfs.c
@@ -91,7 +91,7 @@ static ssize_t acpi_table_aml_read(struct config_item *cfg,
 
 CONFIGFS_BIN_ATTR(acpi_table_, aml, NULL, MAX_ACPI_TABLE_SIZE);
 
-static struct configfs_bin_attribute *acpi_table_bin_attrs[] = {
+static const struct configfs_bin_attribute *const acpi_table_bin_attrs[] = {
 	&acpi_table_attr_aml,
 	NULL,
 };

drivers/gpu/drm/xe/xe_configfs.c

View file

diff --git a/drivers/gpu/drm/xe/xe_configfs.c b/drivers/gpu/drm/xe/xe_configfs.c
index 052cce9..842c180 100644
--- a/drivers/gpu/drm/xe/xe_configfs.c
+++ b/drivers/gpu/drm/xe/xe_configfs.c
@@ -886,7 +886,7 @@ static struct configfs_item_operations xe_config_device_ops = {
 };
 
 static bool xe_config_device_is_visible(struct config_item *item,
-					struct configfs_attribute *attr, int n)
+					const struct configfs_attribute *attr, int n)
 {
 	struct xe_config_group_device *dev = to_xe_config_group_device(item);
 
@@ -981,7 +981,7 @@ static struct configfs_attribute *xe_config_sriov_attrs[] = {
 };
 
 static bool xe_config_sriov_is_visible(struct config_item *item,
-				       struct configfs_attribute *attr, int n)
+				       const struct configfs_attribute *attr, int n)
 {
 	struct xe_config_group_device *dev = to_xe_config_group_device(item->ci_parent);
 

drivers/virt/coco/guest/report.c

View file

diff --git a/drivers/virt/coco/guest/report.c b/drivers/virt/coco/guest/report.c
index b254a14..ad400fb 100644
--- a/drivers/virt/coco/guest/report.c
+++ b/drivers/virt/coco/guest/report.c
@@ -356,7 +356,7 @@ static struct configfs_attribute *tsm_report_attrs[] = {
 	NULL,
 };
 
-static struct configfs_bin_attribute *tsm_report_bin_attrs[] = {
+static const struct configfs_bin_attribute *const tsm_report_bin_attrs[] = {
 	[TSM_REPORT_INBLOB] = &tsm_report_attr_inblob,
 	[TSM_REPORT_OUTBLOB] = &tsm_report_attr_outblob,
 	[TSM_REPORT_AUXBLOB] = &tsm_report_attr_auxblob,
@@ -381,7 +381,7 @@ static struct configfs_item_operations tsm_report_item_ops = {
 };
 
 static bool tsm_report_is_visible(struct config_item *item,
-				  struct configfs_attribute *attr, int n)
+				  const struct configfs_attribute *attr, int n)
 {
 	guard(rwsem_read)(&tsm_rwsem);
 	if (!provider.ops)
@@ -394,7 +394,7 @@ static bool tsm_report_is_visible(struct config_item *item,
 }
 
 static bool tsm_report_is_bin_visible(struct config_item *item,
-				      struct configfs_bin_attribute *attr, int n)
+				      const struct configfs_bin_attribute *attr, int n)
 {
 	guard(rwsem_read)(&tsm_rwsem);
 	if (!provider.ops)

fs/configfs/configfs_internal.h

View file

diff --git a/fs/configfs/configfs_internal.h b/fs/configfs/configfs_internal.h
index 860f1b6..5f627e5 100644
--- a/fs/configfs/configfs_internal.h
+++ b/fs/configfs/configfs_internal.h
@@ -104,17 +104,17 @@ static inline struct config_item * to_item(struct dentry * dentry)
 	return ((struct config_item *) sd->s_element);
 }
 
-static inline struct configfs_attribute * to_attr(struct dentry * dentry)
+static inline const struct configfs_attribute * to_attr(struct dentry * dentry)
 {
 	struct configfs_dirent * sd = dentry->d_fsdata;
-	return ((struct configfs_attribute *) sd->s_element);
+	return ((const struct configfs_attribute *) sd->s_element);
 }
 
-static inline struct configfs_bin_attribute *to_bin_attr(struct dentry *dentry)
+static inline const struct configfs_bin_attribute *to_bin_attr(struct dentry *dentry)
 {
-	struct configfs_attribute *attr = to_attr(dentry);
+	const struct configfs_attribute *attr = to_attr(dentry);
 
-	return container_of(attr, struct configfs_bin_attribute, cb_attr);
+	return container_of_const(attr, struct configfs_bin_attribute, cb_attr);
 }
 
 static inline struct config_item *configfs_get_config_item(struct dentry *dentry)

fs/configfs/dir.c

View file

diff --git a/fs/configfs/dir.c b/fs/configfs/dir.c
index f85b945..0c80fee 100644
--- a/fs/configfs/dir.c
+++ b/fs/configfs/dir.c
@@ -470,7 +470,7 @@ static struct dentry * configfs_lookup(struct inode *dir,
 		 */
 		if ((sd->s_type & CONFIGFS_NOT_PINNED) &&
 		    !strcmp(configfs_get_name(sd), dentry->d_name.name)) {
-			struct configfs_attribute *attr = sd->s_element;
+			const struct configfs_attribute *attr = sd->s_element;
 			umode_t mode = (attr->ca_mode & S_IALLUGO) | S_IFREG;
 
 			dentry->d_fsdata = configfs_get(sd);
@@ -631,8 +631,8 @@ static int populate_attrs(struct config_item *item)
 {
 	const struct config_item_type *t = item->ci_type;
 	const struct configfs_group_operations *ops;
-	struct configfs_attribute *attr;
-	struct configfs_bin_attribute *bin_attr;
+	const struct configfs_attribute *attr;
+	const struct configfs_bin_attribute *bin_attr;
 	int error = 0;
 	int i;
 
@@ -641,8 +641,8 @@ static int populate_attrs(struct config_item *item)
 
 	ops = t->ct_group_ops;
 
-	if (t->ct_attrs) {
-		for (i = 0; (attr = t->ct_attrs[i]) != NULL; i++) {
+	if (t->ct_attrs_const) {
+		for (i = 0; (attr = t->ct_attrs_const[i]) != NULL; i++) {
 			if (ops && ops->is_visible && !ops->is_visible(item, attr, i))
 				continue;
 

fs/configfs/file.c

View file

diff --git a/fs/configfs/file.c b/fs/configfs/file.c
index a48cece..6460b00 100644
--- a/fs/configfs/file.c
+++ b/fs/configfs/file.c
@@ -41,8 +41,8 @@ struct configfs_buffer {
 	struct config_item	*item;
 	struct module		*owner;
 	union {
-		struct configfs_attribute	*attr;
-		struct configfs_bin_attribute	*bin_attr;
+		const struct configfs_attribute		*attr;
+		const struct configfs_bin_attribute	*bin_attr;
 	};
 };
 
@@ -291,7 +291,7 @@ static int __configfs_open_file(struct inode *inode, struct file *file, int type
 {
 	struct dentry *dentry = file->f_path.dentry;
 	struct configfs_fragment *frag = to_frag(file);
-	struct configfs_attribute *attr;
+	const struct configfs_attribute *attr;
 	struct configfs_buffer *buffer;
 	int error;
 

fs/configfs/inode.c

View file

diff --git a/fs/configfs/inode.c b/fs/configfs/inode.c
index 6ba125d..c92a052 100644
--- a/fs/configfs/inode.c
+++ b/fs/configfs/inode.c
@@ -178,7 +178,7 @@ struct inode *configfs_create(struct dentry *dentry, umode_t mode)
  */
 const unsigned char * configfs_get_name(struct configfs_dirent *sd)
 {
-	struct configfs_attribute *attr;
+	const struct configfs_attribute *attr;
 
 	BUG_ON(!sd || !sd->s_element);
 

include/linux/configfs.h

View file

diff --git a/include/linux/configfs.h b/include/linux/configfs.h
index ef65c75..5bead91 100644
--- a/include/linux/configfs.h
+++ b/include/linux/configfs.h
@@ -66,8 +66,11 @@ struct config_item_type {
 	struct module				*ct_owner;
 	const struct configfs_item_operations	*ct_item_ops;
 	const struct configfs_group_operations	*ct_group_ops;
-	struct configfs_attribute		**ct_attrs;
-	struct configfs_bin_attribute		**ct_bin_attrs;
+	union {
+		struct configfs_attribute		**ct_attrs;
+		const struct configfs_attribute		*const *ct_attrs_const;
+	};
+	const struct configfs_bin_attribute	*const *ct_bin_attrs;
 };
 
 /**
@@ -160,41 +163,41 @@ struct configfs_bin_attribute {
 	ssize_t (*write)(struct config_item *, const void *, size_t);
 };
 
-#define CONFIGFS_BIN_ATTR(_pfx, _name, _priv, _maxsz)		\
-static struct configfs_bin_attribute _pfx##attr_##_name = {	\
-	.cb_attr = {						\
-		.ca_name	= __stringify(_name),		\
-		.ca_mode	= S_IRUGO | S_IWUSR,		\
-		.ca_owner	= THIS_MODULE,			\
-	},							\
-	.cb_private	= _priv,				\
-	.cb_max_size	= _maxsz,				\
-	.read		= _pfx##_name##_read,			\
-	.write		= _pfx##_name##_write,			\
+#define CONFIGFS_BIN_ATTR(_pfx, _name, _priv, _maxsz)			\
+static const struct configfs_bin_attribute _pfx##attr_##_name = {	\
+	.cb_attr = {							\
+		.ca_name	= __stringify(_name),			\
+		.ca_mode	= S_IRUGO | S_IWUSR,			\
+		.ca_owner	= THIS_MODULE,				\
+	},								\
+	.cb_private	= _priv,					\
+	.cb_max_size	= _maxsz,					\
+	.read		= _pfx##_name##_read,				\
+	.write		= _pfx##_name##_write,				\
 }
 
-#define CONFIGFS_BIN_ATTR_RO(_pfx, _name, _priv, _maxsz)	\
-static struct configfs_bin_attribute _pfx##attr_##_name = {	\
-	.cb_attr = {						\
-		.ca_name	= __stringify(_name),		\
-		.ca_mode	= S_IRUGO,			\
-		.ca_owner	= THIS_MODULE,			\
-	},							\
-	.cb_private	= _priv,				\
-	.cb_max_size	= _maxsz,				\
-	.read		= _pfx##_name##_read,			\
+#define CONFIGFS_BIN_ATTR_RO(_pfx, _name, _priv, _maxsz)		\
+static const struct configfs_bin_attribute _pfx##attr_##_name = {	\
+	.cb_attr = {							\
+		.ca_name	= __stringify(_name),			\
+		.ca_mode	= S_IRUGO,				\
+		.ca_owner	= THIS_MODULE,				\
+	},								\
+	.cb_private	= _priv,					\
+	.cb_max_size	= _maxsz,					\
+	.read		= _pfx##_name##_read,				\
 }
 
-#define CONFIGFS_BIN_ATTR_WO(_pfx, _name, _priv, _maxsz)	\
-static struct configfs_bin_attribute _pfx##attr_##_name = {	\
-	.cb_attr = {						\
-		.ca_name	= __stringify(_name),		\
-		.ca_mode	= S_IWUSR,			\
-		.ca_owner	= THIS_MODULE,			\
-	},							\
-	.cb_private	= _priv,				\
-	.cb_max_size	= _maxsz,				\
-	.write		= _pfx##_name##_write,			\
+#define CONFIGFS_BIN_ATTR_WO(_pfx, _name, _priv, _maxsz)		\
+static const struct configfs_bin_attribute _pfx##attr_##_name = {	\
+	.cb_attr = {							\
+		.ca_name	= __stringify(_name),			\
+		.ca_mode	= S_IWUSR,				\
+		.ca_owner	= THIS_MODULE,				\
+	},								\
+	.cb_private	= _priv,					\
+	.cb_max_size	= _maxsz,					\
+	.write		= _pfx##_name##_write,				\
 }
 
 /*
@@ -220,8 +223,8 @@ struct configfs_group_operations {
 	struct config_group *(*make_group)(struct config_group *group, const char *name);
 	void (*disconnect_notify)(struct config_group *group, struct config_item *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,
+	bool (*is_visible)(struct config_item *item, const struct configfs_attribute *attr, int n);
+	bool (*is_bin_visible)(struct config_item *item, const struct configfs_bin_attribute *attr,
 			       int n);
 };
 

rust/kernel/configfs.rs

View file

diff --git a/rust/kernel/configfs.rs b/rust/kernel/configfs.rs
index cd082b8..dbed728 100644
--- a/rust/kernel/configfs.rs
+++ b/rust/kernel/configfs.rs
@@ -135,8 +135,9 @@ pub struct Subsystem<Data> {
 // SAFETY: We do not provide any operations on `Subsystem`.
 unsafe impl<Data> Sync for Subsystem<Data> {}
 
-// SAFETY: Ownership of `Subsystem` can safely be transferred to other threads.
-unsafe impl<Data> Send for Subsystem<Data> {}
+// SAFETY: Ownership of `Subsystem` can safely be transferred to other threads
+// if its data can be transferred as well.
+unsafe impl<Data: Send> Send for Subsystem<Data> {}
 
 impl<Data> Subsystem<Data> {
     /// Create an initializer for a [`Subsystem`].
@@ -249,6 +250,13 @@ pub struct Group<Data> {
     data: Data,
 }
 
+// SAFETY: We do not provide any operations on `Group`.
+unsafe impl<Data> Sync for Group<Data> {}
+
+// SAFETY: Ownership of `Group` can safely be transferred to other threads if
+// its data can be transferred as well.
+unsafe impl<Data: Send> Send for Group<Data> {}
+
 impl<Data> Group<Data> {
     /// Create an initializer for a new group.
     ///
@@ -297,26 +305,39 @@ unsafe impl<Data> HasGroup<Data> for Group<Data> {
 ///
 /// `this` must be a valid pointer.
 ///
-/// If `this` does not represent the root group of a configfs subsystem,
-/// `this` must be a pointer to a `bindings::config_group` embedded in a
-/// `Group<Parent>`.
+/// If `this` is the `su_group` field of a `bindings::configfs_subsystem`, that
+/// `configfs_subsystem` must be embedded in a `Subsystem<Parent>`.
 ///
-/// Otherwise, `this` must be a pointer to a `bindings::config_group` that
-/// is embedded in a `bindings::configfs_subsystem` that is embedded in a
-/// `Subsystem<Parent>`.
+/// Otherwise, `this` must be a pointer to a `bindings::config_group` embedded
+/// in a `Group<Parent>`.
 unsafe fn get_group_data<'a, Parent>(this: *mut bindings::config_group) -> &'a Parent {
     // SAFETY: `this` is a valid pointer.
-    let is_root = unsafe { (*this).cg_subsys.is_null() };
+    let subsys = unsafe { (*this).cg_subsys };
+
+    // `link_group()` in `fs/configfs/dir.c` assigns `cg_subsys` for every
+    // `config_group` attached anywhere in a registered subsystem, including
+    // the subsystem's own `su_group` (which gets a pointer to itself). The
+    // only `config_group` with a NULL `cg_subsys` is the configfs root, and
+    // userspace cannot trigger callbacks on it. The group is therefore the
+    // subsystem's `su_group` iff it equals `&cg_subsys->su_group`.
+    let is_root = !subsys.is_null()
+        && core::ptr::eq(
+            this.cast_const(),
+            // SAFETY: For every `config_group` the configfs core dispatches a
+            // callback on, `cg_subsys` was set by `link_group()` at registration time
+            // and points to a valid `configfs_subsystem` that outlives the callback.
+            unsafe { &raw const (*subsys).su_group },
+        );
 
-    if !is_root {
-        // SAFETY: By C API contact,`this` was returned from a call to
-        // `make_group`. The pointer is known to be embedded within a
-        // `Group<Parent>`.
-        unsafe { &(*Group::<Parent>::container_of(this)).data }
-    } else {
-        // SAFETY: By C API contract, `this` is a pointer to the
-        // `bindings::config_group` field within a `Subsystem<Parent>`.
+    if is_root {
+        // SAFETY: By the above, `this` is the `su_group` field of a
+        // `configfs_subsystem` that, by function safety requirements, is
+        // embedded in a `Subsystem<Parent>`.
         unsafe { &(*Subsystem::container_of(this)).data }
+    } else {
+        // SAFETY: By function safety requirements, `this` is a
+        // `config_group` embedded in a `Group<Parent>`.
+        unsafe { &(*Group::<Parent>::container_of(this)).data }
     }
 }
 
@@ -325,7 +346,9 @@ struct GroupOperationsVTable<Parent, Child>(PhantomData<(Parent, Child)>);
 impl<Parent, Child> GroupOperationsVTable<Parent, Child>
 where
     Parent: GroupOperations<Child = Child>,
-    Child: 'static,
+    // We transfer `Arc<Group<Data>>` across a thread boundary in `make_group`
+    // and `drop_item`.
+    Arc<Group<Child>>: Send,
 {
     /// # Safety
     ///
@@ -344,8 +367,9 @@ where
         this: *mut bindings::config_group,
         name: *const kernel::ffi::c_char,
     ) -> *mut bindings::config_group {
-        // SAFETY: By function safety requirements of this function, this call
-        // is safe.
+        // SAFETY: By function safety requirements, `this` points to a configfs
+        // group containing `Parent`. The `GroupOperations` bound guarantees
+        // that `Parent: Sync`, so it is safe to share it with this thread.
         let parent_data = unsafe { get_group_data(this) };
 
         let group_init = match Parent::make_group(
@@ -390,8 +414,9 @@ where
         this: *mut bindings::config_group,
         item: *mut bindings::config_item,
     ) {
-        // SAFETY: By function safety requirements of this function, this call
-        // is safe.
+        // SAFETY: By function safety requirements, `this` points to a configfs
+        // group containing `Parent`. The `GroupOperations` bound guarantees
+        // that `Parent: Sync`, so it is safe to share it with this thread.
         let parent_data = unsafe { get_group_data(this) };
 
         // SAFETY: By function safety requirements, `item` is embedded in a
@@ -403,7 +428,9 @@ where
 
         if Parent::HAS_DROP_ITEM {
             // SAFETY: We called `into_raw` to produce `r_child_group_ptr` in
-            // `make_group`.
+            // `make_group`. This function may be executing on a different
+            // thread than `into_raw`. As `Arc<Group<Child>>: Send` this
+            // ownership transfer is safe.
             let arc: Arc<Group<Child>> = unsafe { Arc::from_raw(r_child_group_ptr.cast_mut()) };
 
             Parent::drop_item(parent_data, arc.as_arc_borrow());
@@ -434,11 +461,13 @@ struct ItemOperationsVTable<Container, Data>(PhantomData<(Container, Data)>);
 impl<Data> ItemOperationsVTable<Group<Data>, Data>
 where
     Data: 'static,
+    // We transfer `Arc<Group<Data>>` across a thread boundary in `release`.
+    Arc<Group<Data>>: Send,
 {
     /// # Safety
     ///
-    /// `this` must be a pointer to a `bindings::config_group` embedded in a
-    /// `Group<Parent>`.
+    /// `this` must be a pointer to the `cg_item` field of a `bindings::config_group` embedded in a
+    /// valid `Group<Data>`.
     ///
     /// This function will destroy the pointee of `this`. The pointee of `this`
     /// must not be accessed after the function returns.
@@ -450,8 +479,9 @@ where
         // embedded within a `Group<Data>`.
         let r_group_ptr = unsafe { Group::<Data>::container_of(c_group_ptr) };
 
-        // SAFETY: We called `into_raw` on `r_group_ptr` in
-        // `make_group`.
+        // SAFETY: We called `into_raw` on `r_group_ptr` in `make_group`. This
+        // function may be running on a different thread than the thread that
+        // called `into_raw`. As `Arc<Group<Data>>: Send`, this is safe.
         let pin_self: Arc<Group<Data>> = unsafe { Arc::from_raw(r_group_ptr.cast_mut()) };
         drop(pin_self);
     }
@@ -483,12 +513,12 @@ impl<Data> ItemOperationsVTable<Subsystem<Data>, Data> {
 ///
 /// Implement this trait on structs that embed a [`Subsystem`] or a [`Group`].
 #[vtable]
-pub trait GroupOperations {
+pub trait GroupOperations: Sync {
     /// The child data object type.
     ///
     /// This group will create subgroups (subdirectories) backed by this kind of
     /// object.
-    type Child: 'static;
+    type Child: 'static + Send;
 
     /// Creates a new subgroup.
     ///
@@ -555,8 +585,10 @@ where
             // `config_group`.
             unsafe { container_of!(item, bindings::config_group, cg_item) };
 
-        // SAFETY: The function safety requirements for this function satisfy
-        // the conditions for this call.
+        // SAFETY: By function safety requirements, `c_group` points to a
+        // configfs group containing `Data`. The `AttributeOperations` bound
+        // guarantees that `Data: Sync`, so it is safe to share it with this
+        // thread.
         let data: &Data = unsafe { get_group_data(c_group) };
 
         // SAFETY: By function safety requirements, `page` is writable for `PAGE_SIZE`.
@@ -589,8 +621,10 @@ where
         // `config_group`.
             unsafe { container_of!(item, bindings::config_group, cg_item) };
 
-        // SAFETY: The function safety requirements for this function satisfy
-        // the conditions for this call.
+        // SAFETY: By function safety requirements, `c_group` points to a
+        // configfs group containing `Data`. The `AttributeOperations` bound
+        // guarantees that `Data: Sync`, so it is safe to share it with this
+        // thread.
         let data: &Data = unsafe { get_group_data(c_group) };
 
         let ret = O::store(
@@ -643,7 +677,7 @@ where
 pub trait AttributeOperations<const ID: u64 = 0> {
     /// The type of the object that contains the field that is backing the
     /// attribute for this operation.
-    type Data;
+    type Data: Sync;
 
     /// Renders the value of an attribute.
     ///
@@ -749,15 +783,18 @@ macro_rules! impl_item_type {
             ) -> Self
             where
                 Data: GroupOperations<Child = Child>,
-                Child: 'static,
+                Arc<Group<Child>>: Send,
+                Arc<Group<Data>>: Send,
             {
                 Self {
                     item_type: Opaque::new(bindings::config_item_type {
                         ct_owner: owner.as_ptr(),
-                        ct_group_ops: GroupOperationsVTable::<Data, Child>::vtable_ptr().cast_mut(),
-                        ct_item_ops: ItemOperationsVTable::<$tpe, Data>::vtable_ptr().cast_mut(),
-                        ct_attrs: core::ptr::from_ref(attributes).cast_mut().cast(),
-                        ct_bin_attrs: core::ptr::null_mut(),
+                        ct_group_ops: GroupOperationsVTable::<Data, Child>::vtable_ptr(),
+                        ct_item_ops: ItemOperationsVTable::<$tpe, Data>::vtable_ptr(),
+                        __bindgen_anon_1: bindings::config_item_type__bindgen_ty_1 {
+                            ct_attrs_const: core::ptr::from_ref(attributes).cast(),
+                        },
+                        ct_bin_attrs: core::ptr::null(),
                     }),
                     _p: PhantomData,
                 }
@@ -767,14 +804,19 @@ macro_rules! impl_item_type {
             pub const fn new<const N: usize>(
                 owner: &'static ThisModule,
                 attributes: &'static AttributeList<N, Data>,
-            ) -> Self {
+            ) -> Self
+            where
+                Arc<Group<Data>>: Send,
+            {
                 Self {
                     item_type: Opaque::new(bindings::config_item_type {
                         ct_owner: owner.as_ptr(),
-                        ct_group_ops: core::ptr::null_mut(),
-                        ct_item_ops: ItemOperationsVTable::<$tpe, Data>::vtable_ptr().cast_mut(),
-                        ct_attrs: core::ptr::from_ref(attributes).cast_mut().cast(),
-                        ct_bin_attrs: core::ptr::null_mut(),
+                        ct_group_ops: core::ptr::null(),
+                        ct_item_ops: ItemOperationsVTable::<$tpe, Data>::vtable_ptr(),
+                        __bindgen_anon_1: bindings::config_item_type__bindgen_ty_1 {
+                            ct_attrs_const: core::ptr::from_ref(attributes).cast(),
+                        },
+                        ct_bin_attrs: core::ptr::null(),
                     }),
                     _p: PhantomData,
                 }

samples/configfs/configfs_sample.c

View file

diff --git a/samples/configfs/configfs_sample.c b/samples/configfs/configfs_sample.c
index c1b108e..6e3a8e0 100644
--- a/samples/configfs/configfs_sample.c
+++ b/samples/configfs/configfs_sample.c
@@ -84,7 +84,7 @@ CONFIGFS_ATTR_RO(childless_, showme);
 CONFIGFS_ATTR(childless_, storeme);
 CONFIGFS_ATTR_RO(childless_, description);
 
-static struct configfs_attribute *childless_attrs[] = {
+static const struct configfs_attribute *const childless_attrs[] = {
 	&childless_attr_showme,
 	&childless_attr_storeme,
 	&childless_attr_description,
@@ -92,7 +92,7 @@ static struct configfs_attribute *childless_attrs[] = {
 };
 
 static const struct config_item_type childless_type = {
-	.ct_attrs	= childless_attrs,
+	.ct_attrs_const	= childless_attrs,
 	.ct_owner	= THIS_MODULE,
 };
 
@@ -148,7 +148,7 @@ static ssize_t simple_child_storeme_store(struct config_item *item,
 
 CONFIGFS_ATTR(simple_child_, storeme);
 
-static struct configfs_attribute *simple_child_attrs[] = {
+static const struct configfs_attribute *const simple_child_attrs[] = {
 	&simple_child_attr_storeme,
 	NULL,
 };
@@ -164,7 +164,7 @@ static const struct configfs_item_operations simple_child_item_ops = {
 
 static const struct config_item_type simple_child_type = {
 	.ct_item_ops	= &simple_child_item_ops,
-	.ct_attrs	= simple_child_attrs,
+	.ct_attrs_const	= simple_child_attrs,
 	.ct_owner	= THIS_MODULE,
 };
 
@@ -205,7 +205,7 @@ static ssize_t simple_children_description_show(struct config_item *item,
 
 CONFIGFS_ATTR_RO(simple_children_, description);
 
-static struct configfs_attribute *simple_children_attrs[] = {
+static const struct configfs_attribute *const simple_children_attrs[] = {
 	&simple_children_attr_description,
 	NULL,
 };
@@ -230,7 +230,7 @@ static const struct configfs_group_operations simple_children_group_ops = {
 static const struct config_item_type simple_children_type = {
 	.ct_item_ops	= &simple_children_item_ops,
 	.ct_group_ops	= &simple_children_group_ops,
-	.ct_attrs	= simple_children_attrs,
+	.ct_attrs_const	= simple_children_attrs,
 	.ct_owner	= THIS_MODULE,
 };
 
@@ -283,7 +283,7 @@ static ssize_t group_children_description_show(struct config_item *item,
 
 CONFIGFS_ATTR_RO(group_children_, description);
 
-static struct configfs_attribute *group_children_attrs[] = {

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tools/testing/selftests/Makefile

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tools/testing/selftests/filesystems/configfs/.gitignore

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tools/testing/selftests/filesystems/configfs/Makefile

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tools/testing/selftests/filesystems/configfs/config

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tools/testing/selftests/filesystems/configfs/configfs_test.c

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