diff options
Diffstat (limited to 'rust/kernel')
| -rw-r--r-- | rust/kernel/drm/device.rs | 22 | ||||
| -rw-r--r-- | rust/kernel/drm/gem/mod.rs | 13 | ||||
| -rw-r--r-- | rust/kernel/drm/gem/shmem.rs | 6 |
3 files changed, 29 insertions, 12 deletions
diff --git a/rust/kernel/drm/device.rs b/rust/kernel/drm/device.rs index adbafe8db54d..403fc35353c7 100644 --- a/rust/kernel/drm/device.rs +++ b/rust/kernel/drm/device.rs @@ -119,13 +119,20 @@ impl<T: drm::Driver> Device<T> { // compatible `Layout`. let layout = Kmalloc::aligned_layout(Layout::new::<Self>()); + // Use a temporary vtable without a `release` callback until `data` is initialized, so + // init failure can release the DRM device without dropping uninitialized fields. + let alloc_vtable = bindings::drm_driver { + release: None, + ..Self::VTABLE + }; + // SAFETY: - // - `VTABLE`, as a `const` is pinned to the read-only section of the compilation, + // - `alloc_vtable` reference remains valid until no longer used, // - `dev` is valid by its type invarants, let raw_drm: *mut Self = unsafe { bindings::__drm_dev_alloc( dev.as_raw(), - &Self::VTABLE, + &alloc_vtable, layout.size(), mem::offset_of!(Self, dev), ) @@ -133,6 +140,10 @@ impl<T: drm::Driver> Device<T> { .cast(); let raw_drm = NonNull::new(from_err_ptr(raw_drm)?).ok_or(ENOMEM)?; + // SAFETY: `raw_drm` is a valid pointer to `Self`, given that `__drm_dev_alloc` was + // successful. + let drm_dev = unsafe { Self::into_drm_device(raw_drm) }; + // SAFETY: `raw_drm` is a valid pointer to `Self`. let raw_data = unsafe { ptr::addr_of_mut!((*raw_drm.as_ptr()).data) }; @@ -140,15 +151,14 @@ impl<T: drm::Driver> Device<T> { // - `raw_data` is a valid pointer to uninitialized memory. // - `raw_data` will not move until it is dropped. unsafe { data.__pinned_init(raw_data) }.inspect_err(|_| { - // SAFETY: `raw_drm` is a valid pointer to `Self`, given that `__drm_dev_alloc` was - // successful. - let drm_dev = unsafe { Self::into_drm_device(raw_drm) }; - // SAFETY: `__drm_dev_alloc()` was successful, hence `drm_dev` must be valid and the // refcount must be non-zero. unsafe { bindings::drm_dev_put(drm_dev) }; })?; + // SAFETY: `drm_dev` is still private to this function. + unsafe { (*drm_dev).driver = const { &Self::VTABLE } }; + // SAFETY: The reference count is one, and now we take ownership of that reference as a // `drm::Device`. Ok(unsafe { ARef::from_raw(raw_drm) }) diff --git a/rust/kernel/drm/gem/mod.rs b/rust/kernel/drm/gem/mod.rs index 75acda7ba500..01b5bd47a333 100644 --- a/rust/kernel/drm/gem/mod.rs +++ b/rust/kernel/drm/gem/mod.rs @@ -277,8 +277,17 @@ impl<T: DriverObject> Object<T> { // SAFETY: `obj.as_raw()` is guaranteed to be valid by the initialization above. unsafe { (*obj.as_raw()).funcs = &Self::OBJECT_FUNCS }; - // SAFETY: The arguments are all valid per the type invariants. - to_result(unsafe { bindings::drm_gem_object_init(dev.as_raw(), obj.obj.get(), size) })?; + if let Err(err) = + // SAFETY: The arguments are all valid per the type invariants. + to_result(unsafe { + bindings::drm_gem_object_init(dev.as_raw(), obj.obj.get(), size) + }) + { + // SAFETY: `drm_gem_object_init()` initializes the private GEM object state before + // failing, so `drm_gem_private_object_fini()` is the matching cleanup. + unsafe { bindings::drm_gem_private_object_fini(obj.obj.get()) }; + return Err(err); + } // SAFETY: We will never move out of `Self` as `ARef<Self>` is always treated as pinned. let ptr = KBox::into_raw(unsafe { Pin::into_inner_unchecked(obj) }); diff --git a/rust/kernel/drm/gem/shmem.rs b/rust/kernel/drm/gem/shmem.rs index d025fb035195..e1b648920d2f 100644 --- a/rust/kernel/drm/gem/shmem.rs +++ b/rust/kernel/drm/gem/shmem.rs @@ -19,10 +19,8 @@ use crate::{ }, error::to_result, prelude::*, - types::{ - ARef, - Opaque, // - }, // + sync::aref::ARef, + types::Opaque, // }; use core::{ ops::{ |