From: Hyeonggon Yoo <42.hyeyoo@gmail•com>
To: Suren Baghdasaryan <surenb@google•com>
Cc: michel@lespinasse•org, joelaf@google•com, songliubraving@fb•com,
mhocko@suse•com, leewalsh@google•com, david@redhat•com,
peterz@infradead•org, bigeasy@linutronix•de, peterx@redhat•com,
dhowells@redhat•com, linux-mm@kvack•org, edumazet@google•com,
jglisse@google•com, punit.agrawal@bytedance•com, will@kernel•org,
arjunroy@google•com, dave@stgolabs•net, minchan@google•com,
x86@kernel•org, hughd@google•com, willy@infradead•org,
gurua@google•com, mingo@redhat•com,
linux-arm-kernel@lists•infradead.org, rientjes@google•com,
axelrasmussen@google•com, kernel-team@android•com,
soheil@google•com, paulmck@kernel•org, jannh@google•com,
liam.howlett@oracle•com, shakeelb@google•com, luto@kernel•org,
gthelen@google•com, ldufour@linux•ibm.com, vbabka@suse•cz,
posk@google•com, lstoakes@gmail•com, peterjung1337@gmail•com,
linuxppc-dev@lists•ozlabs.org, kent.overstreet@linux•dev,
linux-kernel@vger•kernel.org, hannes@cmpxchg•org,
akpm@linux-foundation•org, tatashin@google•com,
mgorman@techsingularity .net, rppt@kernel•org
Subject: Re: [PATCH 1/1] mm: introduce vm_flags_reset_once to replace WRITE_ONCE vm_flags updates
Date: Wed, 8 Feb 2023 01:46:46 +0000 [thread overview]
Message-ID: <Y+L/BubSzdbpTS4P@localhost> (raw)
In-Reply-To: <20230201000116.1333160-1-surenb@google.com>
On Tue, Jan 31, 2023 at 04:01:16PM -0800, Suren Baghdasaryan wrote:
> Provide vm_flags_reset_once() and replace the vm_flags updates which used
> WRITE_ONCE() to prevent compiler optimizations.
>
> Fixes: 0cce31a0aa0e ("mm: replace vma->vm_flags direct modifications with modifier calls")
> Reported-by: Hyeonggon Yoo <42.hyeyoo@gmail•com>
> Signed-off-by: Suren Baghdasaryan <surenb@google•com>
> ---
> Notes:
> - The patch applies cleanly over mm-unstable
> - The SHA in Fixes: line is from mm-unstable, so is... unstable
>
> include/linux/mm.h | 7 +++++++
> mm/mlock.c | 4 ++--
> 2 files changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index 5bf0ad48faaa..23ce04f6e91e 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -648,6 +648,13 @@ static inline void vm_flags_reset(struct vm_area_struct *vma,
> vm_flags_init(vma, flags);
> }
>
> +static inline void vm_flags_reset_once(struct vm_area_struct *vma,
> + vm_flags_t flags)
> +{
> + mmap_assert_write_locked(vma->vm_mm);
> + WRITE_ONCE(ACCESS_PRIVATE(vma, __vm_flags), flags);
> +}
> +
> static inline void vm_flags_set(struct vm_area_struct *vma,
> vm_flags_t flags)
> {
> diff --git a/mm/mlock.c b/mm/mlock.c
> index ed49459e343e..617469fce96d 100644
> --- a/mm/mlock.c
> +++ b/mm/mlock.c
> @@ -380,7 +380,7 @@ static void mlock_vma_pages_range(struct vm_area_struct *vma,
> */
> if (newflags & VM_LOCKED)
> newflags |= VM_IO;
> - vm_flags_reset(vma, newflags);
> + vm_flags_reset_once(vma, newflags);
>
> lru_add_drain();
> walk_page_range(vma->vm_mm, start, end, &mlock_walk_ops, NULL);
> @@ -388,7 +388,7 @@ static void mlock_vma_pages_range(struct vm_area_struct *vma,
>
> if (newflags & VM_IO) {
> newflags &= ~VM_IO;
> - vm_flags_reset(vma, newflags);
> + vm_flags_reset_once(vma, newflags);
> }
> }
Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail•com>
>
> --
> 2.39.1.456.gfc5497dd1b-goog
>
prev parent reply other threads:[~2023-02-08 1:48 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-01 0:01 [PATCH 1/1] mm: introduce vm_flags_reset_once to replace WRITE_ONCE vm_flags updates Suren Baghdasaryan
2023-02-01 7:43 ` Michal Hocko
2023-02-08 1:46 ` Hyeonggon Yoo [this message]
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