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Tue, 31 Jan 2023 16:01:28 -0800 (PST) Date: Tue, 31 Jan 2023 16:01:16 -0800 Mime-Version: 1.0 X-Mailer: git-send-email 2.39.1.456.gfc5497dd1b-goog Message-ID: <20230201000116.1333160-1-surenb@google.com> Subject: [PATCH 1/1] mm: introduce vm_flags_reset_once to replace WRITE_ONCE vm_flags updates From: Suren Baghdasaryan To: akpm@linux-foundation.org X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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, 42.hyeyoo@gmail.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, surenb@google.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, tatashin@google.com, mgorman@te chsingularity.net, rppt@kernel.org Errors-To: linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" 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 Acked-by: Michal Hocko Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.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); } }