Merge branch 'rust-next' of https://github.com/Rust-for-Linux/linux.git

rust/helpers.c

@@ -16,17 +16,19 @@
  *
  * All symbols are exported as GPL-only to guarantee no GPL-only feature is
  * accidentally exposed.
+ *
+ * Sorted alphabetically.
  */
 
 #include <kunit/test-bug.h>
 #include <linux/bug.h>
 #include <linux/build_bug.h>
 #include <linux/err.h>
 #include <linux/errname.h>
-#include <linux/refcount.h>
 #include <linux/mutex.h>
-#include <linux/spinlock.h>
+#include <linux/refcount.h>
 #include <linux/sched/signal.h>
+#include <linux/spinlock.h>
 #include <linux/wait.h>
 
 __noreturn void rust_helper_BUG(void)

rust/kernel/allocator.rs

@@ -41,16 +41,43 @@ unsafe fn krealloc_aligned(ptr: *mut u8, new_layout: Layout, flags: bindings::gf
 
 unsafe impl GlobalAlloc for KernelAllocator {
     unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
-        // `krealloc()` is used instead of `kmalloc()` because the latter is
-        // an inline function and cannot be bound to as a result.
-        unsafe { bindings::krealloc(ptr::null(), layout.size(), bindings::GFP_KERNEL) as *mut u8 }
+        // SAFETY: `ptr::null_mut()` is null and `layout` has a non-zero size by the function safety
+        // requirement.
+        unsafe { krealloc_aligned(ptr::null_mut(), layout, bindings::GFP_KERNEL) }
     }
 
     unsafe fn dealloc(&self, ptr: *mut u8, _layout: Layout) {
         unsafe {
             bindings::kfree(ptr as *const core::ffi::c_void);
         }
     }
+
+    unsafe fn realloc(&self, ptr: *mut u8, layout: Layout, new_size: usize) -> *mut u8 {
+        // SAFETY:
+        // - `new_size`, when rounded up to the nearest multiple of `layout.align()`, will not
+        //   overflow `isize` by the function safety requirement.
+        // - `layout.align()` is a proper alignment (i.e. not zero and must be a power of two).
+        let layout = unsafe { Layout::from_size_align_unchecked(new_size, layout.align()) };
+
+        // SAFETY:
+        // - `ptr` is either null or a pointer allocated by this allocator by the function safety
+        //   requirement.
+        // - the size of `layout` is not zero because `new_size` is not zero by the function safety
+        //   requirement.
+        unsafe { krealloc_aligned(ptr, layout, bindings::GFP_KERNEL) }
+    }
+
+    unsafe fn alloc_zeroed(&self, layout: Layout) -> *mut u8 {
+        // SAFETY: `ptr::null_mut()` is null and `layout` has a non-zero size by the function safety
+        // requirement.
+        unsafe {
+            krealloc_aligned(
+                ptr::null_mut(),
+                layout,
+                bindings::GFP_KERNEL | bindings::__GFP_ZERO,
+            )
+        }
+    }
 }
 
 #[global_allocator]

rust/kernel/sync/lock.rs

@@ -72,8 +72,8 @@ pub unsafe trait Backend {
 
 /// A mutual exclusion primitive.
 ///
-/// Exposes one of the kernel locking primitives. Which one is exposed depends on the lock backend
-/// specified as the generic parameter `B`.
+/// Exposes one of the kernel locking primitives. Which one is exposed depends on the lock
+/// [`Backend`] specified as the generic parameter `B`.
 #[pin_data]
 pub struct Lock<T: ?Sized, B: Backend> {
     /// The kernel lock object.
@@ -126,7 +126,7 @@ impl<T: ?Sized, B: Backend> Lock<T, B> {
 
 /// A lock guard.
 ///
-/// Allows mutual exclusion primitives that implement the `Backend` trait to automatically unlock
+/// Allows mutual exclusion primitives that implement the [`Backend`] trait to automatically unlock
 /// when a guard goes out of scope. It also provides a safe and convenient way to access the data
 /// protected by the lock.
 #[must_use = "the lock unlocks immediately when the guard is unused"]