linux-kernel - [PATCH v3 21/25] rust: alloc: remove `GlobalAlloc` and `krealloc

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20240801000641.1882-22-dakr@kernel.org>
Date: Thu,  1 Aug 2024 02:02:20 +0200
From: Danilo Krummrich <dakr@...nel.org>
To: ojeda@...nel.org,
	alex.gaynor@...il.com,
	wedsonaf@...il.com,
	boqun.feng@...il.com,
	gary@...yguo.net,
	bjorn3_gh@...tonmail.com,
	benno.lossin@...ton.me,
	a.hindborg@...sung.com,
	aliceryhl@...gle.com,
	akpm@...ux-foundation.org
Cc: daniel.almeida@...labora.com,
	faith.ekstrand@...labora.com,
	boris.brezillon@...labora.com,
	lina@...hilina.net,
	mcanal@...lia.com,
	zhiw@...dia.com,
	acurrid@...dia.com,
	cjia@...dia.com,
	jhubbard@...dia.com,
	airlied@...hat.com,
	ajanulgu@...hat.com,
	lyude@...hat.com,
	linux-kernel@...r.kernel.org,
	rust-for-linux@...r.kernel.org,
	linux-mm@...ck.org,
	Danilo Krummrich <dakr@...nel.org>
Subject: [PATCH v3 21/25] rust: alloc: remove `GlobalAlloc` and `krealloc_aligned`

Now that we have all the `Allocator`s and the kernel `Box` and `Vec`
implementations in place, remove `GlobalAlloc` and `krealloc_aligned`.

Signed-off-by: Danilo Krummrich <dakr@...nel.org>
---
 rust/kernel/alloc/allocator.rs | 63 ++--------------------------------
 1 file changed, 2 insertions(+), 61 deletions(-)

diff --git a/rust/kernel/alloc/allocator.rs b/rust/kernel/alloc/allocator.rs
index 1e53f149db96..fbee89ac3be4 100644
--- a/rust/kernel/alloc/allocator.rs
+++ b/rust/kernel/alloc/allocator.rs
@@ -2,8 +2,8 @@
 
 //! Allocator support.
 
-use super::{flags::*, Flags};
-use core::alloc::{GlobalAlloc, Layout};
+use super::Flags;
+use core::alloc::Layout;
 use core::ptr;
 use core::ptr::NonNull;
 
@@ -39,27 +39,6 @@ fn aligned_size(new_layout: Layout) -> usize {
     layout.size()
 }
 
-/// Calls `krealloc` with a proper size to alloc a new object.
-///
-/// # Safety
-///
-/// - `ptr` can be either null or a pointer which has been allocated by this allocator.
-/// - `new_layout` must have a non-zero size.
-pub(crate) unsafe fn krealloc_aligned(ptr: *mut u8, new_layout: Layout, flags: Flags) -> *mut u8 {
-    // SAFETY:
-    // - `ptr` is either null or a pointer returned from a previous `k{re}alloc()` by the
-    //   function safety requirement.
-    // - `size` is greater than 0 since it's from `layout.size()` (which cannot be zero according
-    //   to the function safety requirement)
-    unsafe {
-        bindings::krealloc(
-            ptr as *const core::ffi::c_void,
-            aligned_size(new_layout),
-            flags.0,
-        ) as *mut u8
-    }
-}
-
 struct ReallocFunc(
     // INVARIANT: One of the following `krealloc`, `vrealloc`, `kvrealloc`.
     unsafe extern "C" fn(*const core::ffi::c_void, usize, u32) -> *mut core::ffi::c_void,
@@ -121,41 +100,6 @@ unsafe fn realloc(
     }
 }
 
-unsafe impl GlobalAlloc for Kmalloc {
-    unsafe fn alloc(&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, 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, 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, GFP_KERNEL | __GFP_ZERO) }
-    }
-}
-
 unsafe impl Allocator for Vmalloc {
     unsafe fn realloc(
         ptr: Option<NonNull<u8>>,
@@ -184,9 +128,6 @@ unsafe fn realloc(
     }
 }
 
-#[global_allocator]
-static ALLOCATOR: Kmalloc = Kmalloc;
-
 // See <https://github.com/rust-lang/rust/pull/86844>.
 #[no_mangle]
 static __rust_no_alloc_shim_is_unstable: u8 = 0;
-- 
2.45.2