On Fri 16-12-22 11:20:12, Mike Kravetz wrote: > zap_page_range was originally designed to unmap pages within an address > range that could span multiple vmas. While working on [1], it was > discovered that all callers of zap_page_range pass a range entirely within > a single vma. In addition, the mmu notification call within zap_page > range does not correctly handle ranges that span multiple vmas as calls > should be vma specific.
Could you spend a sentence or two explaining what is wrong here? > Instead of fixing zap_page_range, change all callers to use the new > routine zap_vma_page_range. zap_vma_page_range is just a wrapper around > zap_page_range_single passing in NULL zap details. The name is also > more in line with other exported routines that operate within a vma. > We can then remove zap_page_range. I would stick with zap_page_range_single rather than adding a new wrapper but nothing really critical. > Also, change madvise_dontneed_single_vma to use this new routine. > > [1] > https://lore.kernel.org/linux-mm/20221114235507.294320-2-mike.krav...@oracle.com/ > Suggested-by: Peter Xu <pet...@redhat.com> > Signed-off-by: Mike Kravetz <mike.krav...@oracle.com> Other than that LGTM Acked-by: Michal Hocko <mho...@suse.com> Thanks! > --- > arch/arm64/kernel/vdso.c | 4 ++-- > arch/powerpc/kernel/vdso.c | 2 +- > arch/powerpc/platforms/book3s/vas-api.c | 2 +- > arch/powerpc/platforms/pseries/vas.c | 2 +- > arch/riscv/kernel/vdso.c | 4 ++-- > arch/s390/kernel/vdso.c | 2 +- > arch/s390/mm/gmap.c | 2 +- > arch/x86/entry/vdso/vma.c | 2 +- > drivers/android/binder_alloc.c | 2 +- > include/linux/mm.h | 7 ++++-- > mm/madvise.c | 4 ++-- > mm/memory.c | 30 ------------------------- > mm/page-writeback.c | 2 +- > net/ipv4/tcp.c | 6 ++--- > 14 files changed, 22 insertions(+), 49 deletions(-) > > diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c > index e59a32aa0c49..a7b10e182f78 100644 > --- a/arch/arm64/kernel/vdso.c > +++ b/arch/arm64/kernel/vdso.c > @@ -141,10 +141,10 @@ int vdso_join_timens(struct task_struct *task, struct > time_namespace *ns) > unsigned long size = vma->vm_end - vma->vm_start; > > if (vma_is_special_mapping(vma, vdso_info[VDSO_ABI_AA64].dm)) > - zap_page_range(vma, vma->vm_start, size); > + zap_vma_page_range(vma, vma->vm_start, size); > #ifdef CONFIG_COMPAT_VDSO > if (vma_is_special_mapping(vma, vdso_info[VDSO_ABI_AA32].dm)) > - zap_page_range(vma, vma->vm_start, size); > + zap_vma_page_range(vma, vma->vm_start, size); > #endif > } > > diff --git a/arch/powerpc/kernel/vdso.c b/arch/powerpc/kernel/vdso.c > index 507f8228f983..479d70fe8c55 100644 > --- a/arch/powerpc/kernel/vdso.c > +++ b/arch/powerpc/kernel/vdso.c > @@ -123,7 +123,7 @@ int vdso_join_timens(struct task_struct *task, struct > time_namespace *ns) > unsigned long size = vma->vm_end - vma->vm_start; > > if (vma_is_special_mapping(vma, &vvar_spec)) > - zap_page_range(vma, vma->vm_start, size); > + zap_vma_page_range(vma, vma->vm_start, size); > } > mmap_read_unlock(mm); > > diff --git a/arch/powerpc/platforms/book3s/vas-api.c > b/arch/powerpc/platforms/book3s/vas-api.c > index eb5bed333750..8f57388b760b 100644 > --- a/arch/powerpc/platforms/book3s/vas-api.c > +++ b/arch/powerpc/platforms/book3s/vas-api.c > @@ -414,7 +414,7 @@ static vm_fault_t vas_mmap_fault(struct vm_fault *vmf) > /* > * When the LPAR lost credits due to core removal or during > * migration, invalidate the existing mapping for the current > - * paste addresses and set windows in-active (zap_page_range in > + * paste addresses and set windows in-active (zap_vma_page_range in > * reconfig_close_windows()). > * New mapping will be done later after migration or new credits > * available. So continue to receive faults if the user space > diff --git a/arch/powerpc/platforms/pseries/vas.c > b/arch/powerpc/platforms/pseries/vas.c > index 4ad6e510d405..2aef8d9295a2 100644 > --- a/arch/powerpc/platforms/pseries/vas.c > +++ b/arch/powerpc/platforms/pseries/vas.c > @@ -760,7 +760,7 @@ static int reconfig_close_windows(struct vas_caps *vcap, > int excess_creds, > * is done before the original mmap() and after the ioctl. > */ > if (vma) > - zap_page_range(vma, vma->vm_start, > + zap_vma_page_range(vma, vma->vm_start, > vma->vm_end - vma->vm_start); > > mmap_write_unlock(task_ref->mm); > diff --git a/arch/riscv/kernel/vdso.c b/arch/riscv/kernel/vdso.c > index e410275918ac..a405119da2c0 100644 > --- a/arch/riscv/kernel/vdso.c > +++ b/arch/riscv/kernel/vdso.c > @@ -127,10 +127,10 @@ int vdso_join_timens(struct task_struct *task, struct > time_namespace *ns) > unsigned long size = vma->vm_end - vma->vm_start; > > if (vma_is_special_mapping(vma, vdso_info.dm)) > - zap_page_range(vma, vma->vm_start, size); > + zap_vma_page_range(vma, vma->vm_start, size); > #ifdef CONFIG_COMPAT > if (vma_is_special_mapping(vma, compat_vdso_info.dm)) > - zap_page_range(vma, vma->vm_start, size); > + zap_vma_page_range(vma, vma->vm_start, size); > #endif > } > > diff --git a/arch/s390/kernel/vdso.c b/arch/s390/kernel/vdso.c > index ff7bf4432229..eccfcd505403 100644 > --- a/arch/s390/kernel/vdso.c > +++ b/arch/s390/kernel/vdso.c > @@ -63,7 +63,7 @@ int vdso_join_timens(struct task_struct *task, struct > time_namespace *ns) > > if (!vma_is_special_mapping(vma, &vvar_mapping)) > continue; > - zap_page_range(vma, vma->vm_start, size); > + zap_vma_page_range(vma, vma->vm_start, size); > break; > } > mmap_read_unlock(mm); > diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c > index 74e1d873dce0..67d998152142 100644 > --- a/arch/s390/mm/gmap.c > +++ b/arch/s390/mm/gmap.c > @@ -722,7 +722,7 @@ void gmap_discard(struct gmap *gmap, unsigned long from, > unsigned long to) > if (is_vm_hugetlb_page(vma)) > continue; > size = min(to - gaddr, PMD_SIZE - (gaddr & ~PMD_MASK)); > - zap_page_range(vma, vmaddr, size); > + zap_vma_page_range(vma, vmaddr, size); > } > mmap_read_unlock(gmap->mm); > } > diff --git a/arch/x86/entry/vdso/vma.c b/arch/x86/entry/vdso/vma.c > index b8f3f9b9e53c..5aafbd19e869 100644 > --- a/arch/x86/entry/vdso/vma.c > +++ b/arch/x86/entry/vdso/vma.c > @@ -116,7 +116,7 @@ int vdso_join_timens(struct task_struct *task, struct > time_namespace *ns) > unsigned long size = vma->vm_end - vma->vm_start; > > if (vma_is_special_mapping(vma, &vvar_mapping)) > - zap_page_range(vma, vma->vm_start, size); > + zap_vma_page_range(vma, vma->vm_start, size); > } > mmap_read_unlock(mm); > > diff --git a/drivers/android/binder_alloc.c b/drivers/android/binder_alloc.c > index 4ad42b0f75cd..f7f10248c742 100644 > --- a/drivers/android/binder_alloc.c > +++ b/drivers/android/binder_alloc.c > @@ -1019,7 +1019,7 @@ enum lru_status binder_alloc_free_page(struct list_head > *item, > if (vma) { > trace_binder_unmap_user_start(alloc, index); > > - zap_page_range(vma, page_addr, PAGE_SIZE); > + zap_vma_page_range(vma, page_addr, PAGE_SIZE); > > trace_binder_unmap_user_end(alloc, index); > } > diff --git a/include/linux/mm.h b/include/linux/mm.h > index 6b28eb9c6ea2..706efaf95783 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -1980,10 +1980,13 @@ struct page *vm_normal_page_pmd(struct vm_area_struct > *vma, unsigned long addr, > > void zap_vma_ptes(struct vm_area_struct *vma, unsigned long address, > unsigned long size); > -void zap_page_range(struct vm_area_struct *vma, unsigned long address, > - unsigned long size); > void zap_page_range_single(struct vm_area_struct *vma, unsigned long address, > unsigned long size, struct zap_details *details); > +static inline void zap_vma_page_range(struct vm_area_struct *vma, > + unsigned long address, unsigned long size) > +{ > + zap_page_range_single(vma, address, size, NULL); > +} > void unmap_vmas(struct mmu_gather *tlb, struct maple_tree *mt, > struct vm_area_struct *start_vma, unsigned long start, > unsigned long end); > diff --git a/mm/madvise.c b/mm/madvise.c > index 87703a19bbef..3c4d9829d4e1 100644 > --- a/mm/madvise.c > +++ b/mm/madvise.c > @@ -787,7 +787,7 @@ static int madvise_free_single_vma(struct vm_area_struct > *vma, > * Application no longer needs these pages. If the pages are dirty, > * it's OK to just throw them away. The app will be more careful about > * data it wants to keep. Be sure to free swap resources too. The > - * zap_page_range_single call sets things up for shrink_active_list to > actually > + * zap_vma_page_range call sets things up for shrink_active_list to actually > * free these pages later if no one else has touched them in the meantime, > * although we could add these pages to a global reuse list for > * shrink_active_list to pick up before reclaiming other pages. > @@ -805,7 +805,7 @@ static int madvise_free_single_vma(struct vm_area_struct > *vma, > static long madvise_dontneed_single_vma(struct vm_area_struct *vma, > unsigned long start, unsigned long end) > { > - zap_page_range_single(vma, start, end - start, NULL); > + zap_vma_page_range(vma, start, end - start); > return 0; > } > > diff --git a/mm/memory.c b/mm/memory.c > index 5b2c137dfb2a..e953a0108278 100644 > --- a/mm/memory.c > +++ b/mm/memory.c > @@ -1687,36 +1687,6 @@ void unmap_vmas(struct mmu_gather *tlb, struct > maple_tree *mt, > mmu_notifier_invalidate_range_end(&range); > } > > -/** > - * zap_page_range - remove user pages in a given range > - * @vma: vm_area_struct holding the applicable pages > - * @start: starting address of pages to zap > - * @size: number of bytes to zap > - * > - * Caller must protect the VMA list > - */ > -void zap_page_range(struct vm_area_struct *vma, unsigned long start, > - unsigned long size) > -{ > - struct maple_tree *mt = &vma->vm_mm->mm_mt; > - unsigned long end = start + size; > - struct mmu_notifier_range range; > - struct mmu_gather tlb; > - MA_STATE(mas, mt, vma->vm_end, vma->vm_end); > - > - lru_add_drain(); > - mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm, > - start, start + size); > - tlb_gather_mmu(&tlb, vma->vm_mm); > - update_hiwater_rss(vma->vm_mm); > - mmu_notifier_invalidate_range_start(&range); > - do { > - unmap_single_vma(&tlb, vma, start, range.end, NULL); > - } while ((vma = mas_find(&mas, end - 1)) != NULL); > - mmu_notifier_invalidate_range_end(&range); > - tlb_finish_mmu(&tlb); > -} > - > /** > * zap_page_range_single - remove user pages in a given range > * @vma: vm_area_struct holding the applicable pages > diff --git a/mm/page-writeback.c b/mm/page-writeback.c > index ad608ef2a243..bd9fe6ff6557 100644 > --- a/mm/page-writeback.c > +++ b/mm/page-writeback.c > @@ -2713,7 +2713,7 @@ void folio_account_cleaned(struct folio *folio, struct > bdi_writeback *wb) > * > * The caller must hold lock_page_memcg(). Most callers have the folio > * locked. A few have the folio blocked from truncation through other > - * means (eg zap_page_range() has it mapped and is holding the page table > + * means (eg zap_vma_page_range() has it mapped and is holding the page table > * lock). This can also be called from mark_buffer_dirty(), which I > * cannot prove is always protected against truncate. > */ > diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c > index c567d5e8053e..afaad3cfed00 100644 > --- a/net/ipv4/tcp.c > +++ b/net/ipv4/tcp.c > @@ -2092,7 +2092,7 @@ static int tcp_zerocopy_vm_insert_batch_error(struct > vm_area_struct *vma, > maybe_zap_len = total_bytes_to_map - /* All bytes to map */ > *length + /* Mapped or pending */ > (pages_remaining * PAGE_SIZE); /* Failed map. */ > - zap_page_range(vma, *address, maybe_zap_len); > + zap_vma_page_range(vma, *address, maybe_zap_len); > err = 0; > } > > @@ -2100,7 +2100,7 @@ static int tcp_zerocopy_vm_insert_batch_error(struct > vm_area_struct *vma, > unsigned long leftover_pages = pages_remaining; > int bytes_mapped; > > - /* We called zap_page_range, try to reinsert. */ > + /* We called zap_vma_page_range, try to reinsert. */ > err = vm_insert_pages(vma, *address, > pending_pages, > &pages_remaining); > @@ -2234,7 +2234,7 @@ static int tcp_zerocopy_receive(struct sock *sk, > total_bytes_to_map = avail_len & ~(PAGE_SIZE - 1); > if (total_bytes_to_map) { > if (!(zc->flags & TCP_RECEIVE_ZEROCOPY_FLAG_TLB_CLEAN_HINT)) > - zap_page_range(vma, address, total_bytes_to_map); > + zap_vma_page_range(vma, address, total_bytes_to_map); > zc->length = total_bytes_to_map; > zc->recv_skip_hint = 0; > } else { > -- > 2.38.1 -- Michal Hocko SUSE Labs
