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Baghdasaryan Cc: akpm@linux-foundation.org, michel@lespinasse.org, jglisse@google.com, mhocko@suse.com, vbabka@suse.cz, hannes@cmpxchg.org, mgorman@techsingularity.net, dave@stgolabs.net, willy@infradead.org, liam.howlett@oracle.com, peterz@infradead.org, ldufour@linux.ibm.com, paulmck@kernel.org, mingo@redhat.com, will@kernel.org, luto@kernel.org, songliubraving@fb.com, peterx@redhat.com, david@redhat.com, dhowells@redhat.com, hughd@google.com, bigeasy@linutronix.de, kent.overstreet@linux.dev, punit.agrawal@bytedance.com, lstoakes@gmail.com, peterjung1337@gmail.com, rientjes@google.com, axelrasmussen@google.com, joelaf@google.com, minchan@google.com, rppt@kernel.org, jannh@google.com, shakeelb@google.com, tatashin@google.com, edumazet@google.com, gthelen@google.com, gurua@google.com, arjunroy@google.com, soheil@google.com, leewalsh@google.com, posk@google.com, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, x86@kernel.org, linux-kernel@vger.kernel.org, kernel-team@android.com, Sebastian Reichel Subject: Re: [PATCH v4 4/7] mm: replace vma->vm_flags direct modifications with modifier calls Message-ID: References: <20230126193752.297968-1-surenb@google.com> <20230126193752.297968-5-surenb@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230126193752.297968-5-surenb@google.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jan 26, 2023 at 11:37:49AM -0800, Suren Baghdasaryan wrote: > Replace direct modifications to vma->vm_flags with calls to modifier > functions to be able to track flag changes and to keep vma locking > correctness. > > Signed-off-by: Suren Baghdasaryan > Acked-by: Michal Hocko > Acked-by: Mel Gorman > Acked-by: Mike Rapoport (IBM) > Acked-by: Sebastian Reichel > --- > arch/arm/kernel/process.c | 2 +- > arch/ia64/mm/init.c | 8 ++++---- > arch/loongarch/include/asm/tlb.h | 2 +- > arch/powerpc/kvm/book3s_xive_native.c | 2 +- > arch/powerpc/mm/book3s64/subpage_prot.c | 2 +- > arch/powerpc/platforms/book3s/vas-api.c | 2 +- > arch/powerpc/platforms/cell/spufs/file.c | 14 +++++++------- > arch/s390/mm/gmap.c | 3 +-- > arch/x86/entry/vsyscall/vsyscall_64.c | 2 +- > arch/x86/kernel/cpu/sgx/driver.c | 2 +- > arch/x86/kernel/cpu/sgx/virt.c | 2 +- > arch/x86/mm/pat/memtype.c | 6 +++--- > arch/x86/um/mem_32.c | 2 +- > drivers/acpi/pfr_telemetry.c | 2 +- > drivers/android/binder.c | 3 +-- > drivers/char/mspec.c | 2 +- > drivers/crypto/hisilicon/qm.c | 2 +- > drivers/dax/device.c | 2 +- > drivers/dma/idxd/cdev.c | 2 +- > drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c | 2 +- > drivers/gpu/drm/amd/amdkfd/kfd_chardev.c | 4 ++-- > drivers/gpu/drm/amd/amdkfd/kfd_doorbell.c | 4 ++-- > drivers/gpu/drm/amd/amdkfd/kfd_events.c | 4 ++-- > drivers/gpu/drm/amd/amdkfd/kfd_process.c | 4 ++-- > drivers/gpu/drm/drm_gem.c | 2 +- > drivers/gpu/drm/drm_gem_dma_helper.c | 3 +-- > drivers/gpu/drm/drm_gem_shmem_helper.c | 2 +- > drivers/gpu/drm/drm_vm.c | 8 ++++---- > drivers/gpu/drm/etnaviv/etnaviv_gem.c | 2 +- > drivers/gpu/drm/exynos/exynos_drm_gem.c | 4 ++-- > drivers/gpu/drm/gma500/framebuffer.c | 2 +- > drivers/gpu/drm/i810/i810_dma.c | 2 +- > drivers/gpu/drm/i915/gem/i915_gem_mman.c | 4 ++-- > drivers/gpu/drm/mediatek/mtk_drm_gem.c | 2 +- > drivers/gpu/drm/msm/msm_gem.c | 2 +- > drivers/gpu/drm/omapdrm/omap_gem.c | 3 +-- > drivers/gpu/drm/rockchip/rockchip_drm_gem.c | 3 +-- > drivers/gpu/drm/tegra/gem.c | 5 ++--- > drivers/gpu/drm/ttm/ttm_bo_vm.c | 3 +-- > drivers/gpu/drm/virtio/virtgpu_vram.c | 2 +- > drivers/gpu/drm/vmwgfx/vmwgfx_ttm_glue.c | 2 +- > drivers/gpu/drm/xen/xen_drm_front_gem.c | 3 +-- > drivers/hsi/clients/cmt_speech.c | 2 +- > drivers/hwtracing/intel_th/msu.c | 2 +- > drivers/hwtracing/stm/core.c | 2 +- > drivers/infiniband/hw/hfi1/file_ops.c | 4 ++-- > drivers/infiniband/hw/mlx5/main.c | 4 ++-- > drivers/infiniband/hw/qib/qib_file_ops.c | 13 ++++++------- > drivers/infiniband/hw/usnic/usnic_ib_verbs.c | 2 +- > drivers/infiniband/hw/vmw_pvrdma/pvrdma_verbs.c | 2 +- > .../media/common/videobuf2/videobuf2-dma-contig.c | 2 +- > drivers/media/common/videobuf2/videobuf2-vmalloc.c | 2 +- > drivers/media/v4l2-core/videobuf-dma-contig.c | 2 +- > drivers/media/v4l2-core/videobuf-dma-sg.c | 4 ++-- > drivers/media/v4l2-core/videobuf-vmalloc.c | 2 +- > drivers/misc/cxl/context.c | 2 +- > drivers/misc/habanalabs/common/memory.c | 2 +- > drivers/misc/habanalabs/gaudi/gaudi.c | 4 ++-- > drivers/misc/habanalabs/gaudi2/gaudi2.c | 8 ++++---- > drivers/misc/habanalabs/goya/goya.c | 4 ++-- > drivers/misc/ocxl/context.c | 4 ++-- > drivers/misc/ocxl/sysfs.c | 2 +- > drivers/misc/open-dice.c | 4 ++-- > drivers/misc/sgi-gru/grufile.c | 4 ++-- > drivers/misc/uacce/uacce.c | 2 +- > drivers/sbus/char/oradax.c | 2 +- > drivers/scsi/cxlflash/ocxl_hw.c | 2 +- > drivers/scsi/sg.c | 2 +- > drivers/staging/media/atomisp/pci/hmm/hmm_bo.c | 2 +- > drivers/staging/media/deprecated/meye/meye.c | 4 ++-- > .../media/deprecated/stkwebcam/stk-webcam.c | 2 +- > drivers/target/target_core_user.c | 2 +- > drivers/uio/uio.c | 2 +- > drivers/usb/core/devio.c | 3 +-- > drivers/usb/mon/mon_bin.c | 3 +-- > drivers/vdpa/vdpa_user/iova_domain.c | 2 +- > drivers/vfio/pci/vfio_pci_core.c | 2 +- > drivers/vhost/vdpa.c | 2 +- > drivers/video/fbdev/68328fb.c | 2 +- > drivers/video/fbdev/core/fb_defio.c | 4 ++-- > drivers/xen/gntalloc.c | 2 +- > drivers/xen/gntdev.c | 4 ++-- > drivers/xen/privcmd-buf.c | 2 +- > drivers/xen/privcmd.c | 4 ++-- > fs/aio.c | 2 +- > fs/cramfs/inode.c | 2 +- > fs/erofs/data.c | 2 +- > fs/exec.c | 4 ++-- > fs/ext4/file.c | 2 +- > fs/fuse/dax.c | 2 +- > fs/hugetlbfs/inode.c | 4 ++-- > fs/orangefs/file.c | 3 +-- > fs/proc/task_mmu.c | 2 +- > fs/proc/vmcore.c | 3 +-- > fs/userfaultfd.c | 2 +- > fs/xfs/xfs_file.c | 2 +- > include/linux/mm.h | 2 +- > kernel/bpf/ringbuf.c | 4 ++-- > kernel/bpf/syscall.c | 4 ++-- > kernel/events/core.c | 2 +- > kernel/kcov.c | 2 +- > kernel/relay.c | 2 +- > mm/madvise.c | 2 +- > mm/memory.c | 6 +++--- > mm/mlock.c | 6 +++--- > mm/mmap.c | 10 +++++----- > mm/mprotect.c | 2 +- > mm/mremap.c | 6 +++--- > mm/nommu.c | 11 ++++++----- > mm/secretmem.c | 2 +- > mm/shmem.c | 2 +- > mm/vmalloc.c | 2 +- > net/ipv4/tcp.c | 4 ++-- > security/selinux/selinuxfs.c | 6 +++--- > sound/core/oss/pcm_oss.c | 2 +- > sound/core/pcm_native.c | 9 +++++---- > sound/soc/pxa/mmp-sspa.c | 2 +- > sound/usb/usx2y/us122l.c | 4 ++-- > sound/usb/usx2y/usX2Yhwdep.c | 2 +- > sound/usb/usx2y/usx2yhwdeppcm.c | 2 +- > 120 files changed, 188 insertions(+), 199 deletions(-) > Hello Suren, [...] Whoa, it's so long. Mostly looks fine but two things I'm not sure about: > diff --git a/drivers/misc/open-dice.c b/drivers/misc/open-dice.c > index 9dda47b3fd70..7be4e6c9f120 100644 > --- a/drivers/misc/open-dice.c > +++ b/drivers/misc/open-dice.c > @@ -95,12 +95,12 @@ static int open_dice_mmap(struct file *filp, struct vm_area_struct *vma) > if (vma->vm_flags & VM_WRITE) > return -EPERM; > /* Ensure userspace cannot acquire VM_WRITE later. */ > - vma->vm_flags &= ~VM_MAYWRITE; > + vm_flags_clear(vma, VM_MAYSHARE); > } I think it should be: s/VM_MAYSHARE/VM_MAYWRITE/ > diff --git a/mm/mlock.c b/mm/mlock.c > index 5c4fff93cd6b..ed49459e343e 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; > - WRITE_ONCE(vma->vm_flags, newflags); > + vm_flags_reset(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; > - WRITE_ONCE(vma->vm_flags, newflags); > + vm_flags_reset(vma, newflags); > } > } wondering the if the comment above is still true? /* * There is a slight chance that concurrent page migration, * or page reclaim finding a page of this now-VM_LOCKED vma, * will call mlock_vma_folio() and raise page's mlock_count: * double counting, leaving the page unevictable indefinitely. * Communicate this danger to mlock_vma_folio() with VM_IO, * which is a VM_SPECIAL flag not allowed on VM_LOCKED vmas. * mmap_lock is held in write mode here, so this weird * combination should not be visible to other mmap_lock users; * but WRITE_ONCE so rmap walkers must see VM_IO if VM_LOCKED. */ does ACCESS_PRIVATE() still guarentee that compiler cannot mysteriously optimize writes like WRITE_ONCE()?