From: Nick Desaulniers <ndesaulniers@google.com>
To: Will Deacon <will@kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
Linux Memory Management List <linux-mm@kvack.org>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Jan Kara <jack@suse.cz>, Minchan Kim <minchan@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Vinayak Menon <vinmenon@codeaurora.org>,
Hugh Dickins <hughd@google.com>,
kernel-team <kernel-team@android.com>
Subject: Re: [PATCH v4 8/8] mm: Mark anonymous struct field of 'struct vm_fault' as 'const'
Date: Wed, 20 Jan 2021 10:27:04 -0800 [thread overview]
Message-ID: <CAKwvOd=B+tMi7-82Q8hEYnQ+BzkLDygOhMh6cQ2L+3SaL+F4tQ@mail.gmail.com> (raw)
In-Reply-To: <20210120173612.20913-9-will@kernel.org>
On Wed, Jan 20, 2021 at 9:36 AM Will Deacon <will@kernel.org> wrote:
>
> The fields of this struct are only ever read after being initialised, so
> mark it 'const' before somebody tries to modify it again.
>
> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> Cc: Linus Torvalds <torvalds@linux-foundation.org>
> Signed-off-by: Will Deacon <will@kernel.org>
> ---
> include/linux/mm.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index e0f056753bef..7ff3d9817d38 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -514,7 +514,7 @@ static inline bool fault_flag_allow_retry_first(unsigned int flags)
> * pgoff should be used in favour of virtual_address, if possible.
> */
> struct vm_fault {
> - struct {
> + const struct {
> struct vm_area_struct *vma; /* Target VMA */
> gfp_t gfp_mask; /* gfp mask to be used for allocations */
> pgoff_t pgoff; /* Logical page offset based on vma */
Is there a difference between:
+ const struct {
+ struct vm_area_struct *vma; /* Target VMA */
+ gfp_t gfp_mask; /* gfp mask to be used
for allocations */
+ pgoff_t pgoff; /* Logical page offset
based on vma */
+ unsigned long address; /* Faulting virtual address */
+ };
vs
+ struct {
+ struct vm_area_struct * const vma; /* Target VMA */
+ const gfp_t gfp_mask; /* gfp mask to
be used for allocations */
+ const pgoff_t pgoff; /* Logical page
offset based on vma */
+ const unsigned long address; /* Faulting
virtual address */
+ };
ie. marking the members const vs the anonymous struct? Does anything
need to change in the use of these structures?
> --
> 2.30.0.284.gd98b1dd5eaa7-goog
>
--
Thanks,
~Nick Desaulniers
next prev parent reply other threads:[~2021-01-20 18:27 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-20 17:36 [PATCH v4 0/8] Create 'old' ptes for faultaround mappings on arm64 with hardware access flag Will Deacon
2021-01-20 17:36 ` [PATCH v4 1/8] mm: Cleanup faultaround and finish_fault() codepaths Will Deacon
2021-01-20 17:36 ` [PATCH v4 2/8] mm: Allow architectures to request 'old' entries when prefaulting Will Deacon
2021-01-20 17:36 ` [PATCH v4 3/8] arm64: mm: Implement arch_wants_old_prefaulted_pte() Will Deacon
2021-01-20 17:36 ` [PATCH v4 4/8] mm: Move immutable fields of 'struct vm_fault' into anonymous struct Will Deacon
2021-01-20 18:13 ` Nick Desaulniers
2021-01-21 12:48 ` Will Deacon
2021-01-20 17:36 ` [PATCH v4 5/8] mm: Pass 'address' to map to do_set_pte() and drop FAULT_FLAG_PREFAULT Will Deacon
2021-01-20 17:36 ` [PATCH v4 6/8] mm: Avoid modifying vmf.address in __collapse_huge_page_swapin() Will Deacon
2021-01-20 17:36 ` [PATCH v4 7/8] mm: Use static initialisers for immutable fields of 'struct vm_fault' Will Deacon
2021-01-20 18:21 ` Nick Desaulniers
2021-01-21 12:50 ` Will Deacon
2021-01-20 17:36 ` [PATCH v4 8/8] mm: Mark anonymous struct field of 'struct vm_fault' as 'const' Will Deacon
2021-01-20 18:27 ` Nick Desaulniers [this message]
2021-01-20 19:02 ` Linus Torvalds
2021-01-21 13:11 ` Will Deacon
2021-01-21 19:24 ` Nick Desaulniers
2021-01-21 21:28 ` Will Deacon
2021-01-22 19:10 ` Nick Desaulniers
2021-01-22 19:27 ` Will Deacon
2021-01-22 17:47 ` Linus Torvalds
2021-01-26 23:08 ` [PATCH v4 0/8] Create 'old' ptes for faultaround mappings on arm64 with hardware access flag Will Deacon
2021-01-26 23:28 ` Hugh Dickins
2021-01-27 17:16 ` Will Deacon
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