github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-10-22 23:01:49 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

Rust configfs changes for v7.4-rc1

Browse Source 
Three changes for the Rust configfs bindings. One typo fix for a safety comment and two bug fixes.
 -----BEGIN PGP SIGNATURE-----
 
 iQJKBAABCgA0FiEEV4rZyNlmdiYqwGqG+lApCKrFvdAFAmrGURoWHGEuaGluZGJv
 cmdAa2VybmVsLm9yZwAKCRD6UCkIqsW90CvkD/wLBRiEaAbavO414YzZgn34Gnfc
 G0YfJ66bk9NFjLHf/ckpFZwFOEPw/3gFs2vtjAgLxs3Dmv7YIh8ZWJ8QBEcRLodT
 hv6cc2bxOQ4consnfZRtdkPk94zhEqXRA22Yddt2lO2EEoZ4o1gk1FEpBYRszEQf
 IvOynDRIdqQBwlez051Gk1/OcKqaTJSe2EnYri6G79Tzc56Dw+wASOCTn0IkpCQJ
 v16Vp3bBfaDHBXcXdN1S1xNR8fpX3Gz+GjtgXZnx3Z1+7qNyX/8Fjgragk9MuP48
 mWVJjQ43tNNV3ebIlwW2KTo3m+3EODtn1gYnRi9Qfn41BFdcdbDB3xmx6fC7w+NI
 33MR/t12aZuLA+JkPiII7HAfmBL9+2ERXDilZAWSF22H0TdLRBYDL10u+Bp+bMl8
 GF08MQrERJbts/olHGliz3yfO5YqqCHorbCNbInK8vUAg0bLPLduv1ufsYxl0cGC
 gWJ3rcbhmGvUHT/UhdIEN5lqK9ptZRHZjpQBc6jVAHDofy31UBGAtshiMZIuCDKV
 39xYzL3MTEFAQjCNTicAnFd4ihzMAyKo6ASM+FrSX4D2MLPk+gkQdLNIgk1lWmdn
 CjkCQnxTp2SGhtMW9RFOjycLGjCCgX+omkcPaYt1chjglih6TDISf/7ABNE6QylW
 +i993IjHjc+NDMrW6g==
 =AtTm
 -----END PGP SIGNATURE-----

Merge tag 'rust-configfs-for-v7.4-rc1' of https://git.kernel.org/pub/scm/linux/kernel/git/a.hindborg/linux into updates-v7.4

Rust configfs changes for v7.4-rc1

Three changes for the Rust configfs bindings. One typo fix for a safety comment and two bug fixes.

* tag 'rust-configfs-for-v7.4-rc1' of https://git.kernel.org/pub/scm/linux/kernel/git/a.hindborg/linux:
  rust: configfs: fix data offset calculation for subsystem callbacks
  rust: configfs: require thread-safe callback data
  rust: configfs: fix release safety documentation
This commit is contained in:
Breno Leitao 2026-10-16 09:17:46 -07:00
commit 6c1fa55e28
1 changed files with 74 additions and 36 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

110
rust/kernel/configfs.rs
View File

@ -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 fn container_of(group: *const bindings::config_group) -> *const Self {
///
/// `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 };
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>`.
// `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 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 @@ unsafe fn get_group_data<'a, Parent>(this: *mut bindings::config_group) -> &'a P
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 @@ impl<Parent, Child> GroupOperationsVTable<Parent, Child>
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 @@ impl<Parent, Child> GroupOperationsVTable<Parent, Child>
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 @@ impl<Parent, Child> GroupOperationsVTable<Parent, Child>
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 @@ const fn vtable_ptr() -> *const bindings::configfs_group_operations {
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 @@ impl<Data> ItemOperationsVTable<Group<Data>, Data>
// 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 @@ const fn vtable_ptr() -> *const bindings::configfs_item_operations {
///
/// 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 @@ impl<const ID: u64, O, Data> Attribute<ID, O, Data>
// `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 @@ impl<const ID: u64, O, Data> Attribute<ID, O, Data>
// `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 @@ pub const fn new(name: &'static CStr) -> Self {
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.
///
@ -749,7 +783,8 @@ pub const fn new_with_child_ctor<const N: usize, Child>(
) -> 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 {
@ -769,7 +804,10 @@ pub const fn new_with_child_ctor<const N: usize, Child>(
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(),