From patchwork Fri Mar 7 22:49:34 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Miguel Ojeda X-Patchwork-Id: 14008997 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D4DCE258CD6; Fri, 7 Mar 2025 22:51:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741387909; cv=none; b=UvmYSH6Res1HOJXVSk8yiOunayW1rjBZjBt/EFbvI37B9f8F/qpSvkTCJkFSTIvP7hBDc9pe/tSB2MwgNL9DWxowApZ+C2/jHHnO3Gz+BoYSh8AyhmTAIsvxlzVv6X9MqAVwOahceXZZfKRZbpvvx3IyB+xG8uwvMO1RKRNTpKs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741387909; c=relaxed/simple; bh=QQFGSeAZ73dVTmlSggmrZRidVgx4iUgNI8dMdqntHik=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=G2B+36ZELYNtZwlK/WbNBg451MhK2ZGdnzrYToNEBqXFSknAW+8h7aL8YrBUgCdpc6gmOso+2Wnf2ogl7eylzMkVYbubjRYwAUch8/jLje1RMfl5iQSgo6uT87Mz52IKE4sEHFmmr3pDUtn6t8hS7dyo9ZFC5mEEMSeopTY/OVs= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=a3Y1i65q; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="a3Y1i65q" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7D3ADC4CEE5; Fri, 7 Mar 2025 22:51:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1741387909; bh=QQFGSeAZ73dVTmlSggmrZRidVgx4iUgNI8dMdqntHik=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=a3Y1i65q476W8vVdoDHb3GM2EYON4pyi+LgC4Zu6cFfe8kvs9ycy+w7qVM5Hv81YG eVWQVxeTLtnc1OxMxEnj0vXIFAxHP3UJz8oeaHzgU8QzSI6tE9kF1UQg+1K05qhfnf QoTCCjgvrO7LnkmHqGy9kGo5Dx/Rx+wJ4VL1B/svqvcAX3BSNbAYJbPb92VTuwXVEf 2a20l74NbOobIhDCCS4d7elBw6caEUP459nUvNFfXKHrscSiNZhsE32r8mrsVsmfwU v9slfKe9MatSHo/4458lG/UqtqSLIW8bxHjADNFnvILUWUFimrZxFfMXd1wykA0KYG dyB/6u5WBg0Pg== From: Miguel Ojeda To: Greg Kroah-Hartman , Sasha Levin , stable@vger.kernel.org Cc: Danilo Krummrich , Alice Ryhl , Alyssa Ross , NoisyCoil , patches@lists.linux.dev, Miguel Ojeda Subject: [PATCH 6.12.y 27/60] rust: alloc: implement `Vmalloc` allocator Date: Fri, 7 Mar 2025 23:49:34 +0100 Message-ID: <20250307225008.779961-28-ojeda@kernel.org> In-Reply-To: <20250307225008.779961-1-ojeda@kernel.org> References: <20250307225008.779961-1-ojeda@kernel.org> Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Danilo Krummrich commit 61c004781d6b928443052e7a6cf84b35d4f61401 upstream. Implement `Allocator` for `Vmalloc`, the kernel's virtually contiguous allocator, typically used for larger objects, (much) larger than page size. All memory allocations made with `Vmalloc` end up in `vrealloc()`. Reviewed-by: Alice Ryhl Reviewed-by: Benno Lossin Reviewed-by: Gary Guo Signed-off-by: Danilo Krummrich Link: https://lore.kernel.org/r/20241004154149.93856-9-dakr@kernel.org Signed-off-by: Miguel Ojeda --- rust/helpers/helpers.c | 1 + rust/helpers/vmalloc.c | 9 +++++++ rust/kernel/alloc/allocator.rs | 37 +++++++++++++++++++++++++++++ rust/kernel/alloc/allocator_test.rs | 1 + 4 files changed, 48 insertions(+) create mode 100644 rust/helpers/vmalloc.c diff --git a/rust/helpers/helpers.c b/rust/helpers/helpers.c index 30f40149f3a9..20a0c69d5cc7 100644 --- a/rust/helpers/helpers.c +++ b/rust/helpers/helpers.c @@ -22,5 +22,6 @@ #include "spinlock.c" #include "task.c" #include "uaccess.c" +#include "vmalloc.c" #include "wait.c" #include "workqueue.c" diff --git a/rust/helpers/vmalloc.c b/rust/helpers/vmalloc.c new file mode 100644 index 000000000000..80d34501bbc0 --- /dev/null +++ b/rust/helpers/vmalloc.c @@ -0,0 +1,9 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include + +void * __must_check __realloc_size(2) +rust_helper_vrealloc(const void *p, size_t size, gfp_t flags) +{ + return vrealloc(p, size, flags); +} diff --git a/rust/kernel/alloc/allocator.rs b/rust/kernel/alloc/allocator.rs index 272c581e24a0..ee4c828cbd58 100644 --- a/rust/kernel/alloc/allocator.rs +++ b/rust/kernel/alloc/allocator.rs @@ -15,6 +15,7 @@ use crate::alloc::{AllocError, Allocator}; use crate::bindings; +use crate::pr_warn; /// The contiguous kernel allocator. /// @@ -24,6 +25,15 @@ /// For more details see [self]. pub struct Kmalloc; +/// The virtually contiguous kernel allocator. +/// +/// `Vmalloc` allocates pages from the page level allocator and maps them into the contiguous kernel +/// virtual space. It is typically used for large allocations. The memory allocated with this +/// allocator is not physically contiguous. +/// +/// For more details see [self]. +pub struct Vmalloc; + /// Returns a proper size to alloc a new object aligned to `new_layout`'s alignment. fn aligned_size(new_layout: Layout) -> usize { // Customized layouts from `Layout::from_size_align()` can have size < align, so pad first. @@ -63,6 +73,9 @@ impl ReallocFunc { // INVARIANT: `krealloc` satisfies the type invariants. const KREALLOC: Self = Self(bindings::krealloc); + // INVARIANT: `vrealloc` satisfies the type invariants. + const VREALLOC: Self = Self(bindings::vrealloc); + /// # Safety /// /// This method has the same safety requirements as [`Allocator::realloc`]. @@ -168,6 +181,30 @@ unsafe fn alloc_zeroed(&self, layout: Layout) -> *mut u8 { } } +// SAFETY: `realloc` delegates to `ReallocFunc::call`, which guarantees that +// - memory remains valid until it is explicitly freed, +// - passing a pointer to a valid memory allocation is OK, +// - `realloc` satisfies the guarantees, since `ReallocFunc::call` has the same. +unsafe impl Allocator for Vmalloc { + #[inline] + unsafe fn realloc( + ptr: Option>, + layout: Layout, + old_layout: Layout, + flags: Flags, + ) -> Result, AllocError> { + // TODO: Support alignments larger than PAGE_SIZE. + if layout.align() > bindings::PAGE_SIZE { + pr_warn!("Vmalloc does not support alignments larger than PAGE_SIZE yet.\n"); + return Err(AllocError); + } + + // SAFETY: If not `None`, `ptr` is guaranteed to point to valid memory, which was previously + // allocated with this `Allocator`. + unsafe { ReallocFunc::VREALLOC.call(ptr, layout, old_layout, flags) } + } +} + #[global_allocator] static ALLOCATOR: Kmalloc = Kmalloc; diff --git a/rust/kernel/alloc/allocator_test.rs b/rust/kernel/alloc/allocator_test.rs index c5d325506f0c..32a1450c4d39 100644 --- a/rust/kernel/alloc/allocator_test.rs +++ b/rust/kernel/alloc/allocator_test.rs @@ -7,6 +7,7 @@ use core::ptr::NonNull; pub struct Kmalloc; +pub type Vmalloc = Kmalloc; unsafe impl Allocator for Kmalloc { unsafe fn realloc(