| Message ID | 20210908163622.214951-1-peterx@redhat.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | mm: A few cleanup patches around zap, shmem and uffd | expand |
* Peter Xu <peterx@redhat.com> [210908 12:36]: > The first_index/last_index parameters in zap_details are actually only used in > unmap_mapping_range_tree(). At the meantime, this function is only called by > unmap_mapping_pages() once. Instead of passing these two variables through the > whole stack of page zapping code, remove them from zap_details and let them > simply be parameters of unmap_mapping_range_tree(), which is inlined. > > Reviewed-by: Alistair Popple <apopple@nvidia.com> > Reviewed-by: David Hildenbrand <david@redhat.com> > Signed-off-by: Peter Xu <peterx@redhat.com> > --- > include/linux/mm.h | 2 -- > mm/memory.c | 29 ++++++++++++++++------------- > 2 files changed, 16 insertions(+), 15 deletions(-) > > diff --git a/include/linux/mm.h b/include/linux/mm.h > index 73a52aba448f..d1126f731221 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -1722,8 +1722,6 @@ extern void user_shm_unlock(size_t, struct ucounts *); > */ > struct zap_details { > struct address_space *check_mapping; /* Check page->mapping if set */ > - pgoff_t first_index; /* Lowest page->index to unmap */ > - pgoff_t last_index; /* Highest page->index to unmap */ > struct page *single_page; /* Locked page to be unmapped */ > }; > > diff --git a/mm/memory.c b/mm/memory.c > index 7b095f07c4ef..6bba3b9fef7c 100644 > --- a/mm/memory.c > +++ b/mm/memory.c > @@ -3321,20 +3321,20 @@ static void unmap_mapping_range_vma(struct vm_area_struct *vma, > } > > static inline void unmap_mapping_range_tree(struct rb_root_cached *root, > + pgoff_t first_index, > + pgoff_t last_index, > struct zap_details *details) > { > struct vm_area_struct *vma; > pgoff_t vba, vea, zba, zea; > > - vma_interval_tree_foreach(vma, root, > - details->first_index, details->last_index) { > - > + vma_interval_tree_foreach(vma, root, first_index, last_index) { > vba = vma->vm_pgoff; > vea = vba + vma_pages(vma) - 1; > - zba = details->first_index; > + zba = first_index; > if (zba < vba) > zba = vba; > - zea = details->last_index; > + zea = last_index; > if (zea > vea) > zea = vea; > > @@ -3360,18 +3360,21 @@ void unmap_mapping_page(struct page *page) > { > struct address_space *mapping = page->mapping; > struct zap_details details = { }; > + pgoff_t first_index, last_index; > > VM_BUG_ON(!PageLocked(page)); > VM_BUG_ON(PageTail(page)); > > + first_index = page->index; > + last_index = page->index + thp_nr_pages(page) - 1; > + > details.check_mapping = mapping; > - details.first_index = page->index; > - details.last_index = page->index + thp_nr_pages(page) - 1; > details.single_page = page; > > i_mmap_lock_write(mapping); > if (unlikely(!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))) > - unmap_mapping_range_tree(&mapping->i_mmap, &details); > + unmap_mapping_range_tree(&mapping->i_mmap, first_index, > + last_index, &details); > i_mmap_unlock_write(mapping); > } > > @@ -3390,17 +3393,17 @@ void unmap_mapping_page(struct page *page) > void unmap_mapping_pages(struct address_space *mapping, pgoff_t start, > pgoff_t nr, bool even_cows) > { > + pgoff_t first_index = start, last_index = start + nr - 1; Nit: If you respin, can first_index and last_index be two lines please? > struct zap_details details = { }; > > details.check_mapping = even_cows ? NULL : mapping; > - details.first_index = start; > - details.last_index = start + nr - 1; > - if (details.last_index < details.first_index) > - details.last_index = ULONG_MAX; Nit: Maybe throw a comment about this being overflow check, if you respin. > + if (last_index < first_index) > + last_index = ULONG_MAX; > > i_mmap_lock_write(mapping); > if (unlikely(!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))) > - unmap_mapping_range_tree(&mapping->i_mmap, &details); > + unmap_mapping_range_tree(&mapping->i_mmap, first_index, > + last_index, &details); > i_mmap_unlock_write(mapping); > } > > -- > 2.31.1 > Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
On Thu, Sep 09, 2021 at 02:54:37AM +0000, Liam Howlett wrote: > > @@ -3390,17 +3393,17 @@ void unmap_mapping_page(struct page *page) > > void unmap_mapping_pages(struct address_space *mapping, pgoff_t start, > > pgoff_t nr, bool even_cows) > > { > > + pgoff_t first_index = start, last_index = start + nr - 1; > > Nit: If you respin, can first_index and last_index be two lines please? Sure. > > > struct zap_details details = { }; > > > > details.check_mapping = even_cows ? NULL : mapping; > > - details.first_index = start; > > - details.last_index = start + nr - 1; > > - if (details.last_index < details.first_index) > > - details.last_index = ULONG_MAX; > > Nit: Maybe throw a comment about this being overflow check, if you > respin. It may not be "only" an overflow check, e.g., both unmap_mapping_range() and unmap_mapping_pages() allows taking the npages to be zero: For unmap_mapping_range: * @holelen: size of prospective hole in bytes. This will be rounded * up to a PAGE_SIZE boundary. A holelen of zero truncates to the * end of the file. For unmap_mapping_pages: * @nr: Number of pages to be unmapped. 0 to unmap to end of file. So we must set it to ULONG_MAX to make sure nr==0 will work like that. I won't bother adding a comment, but if to add it I'll probably also mention about that part on allowing a nr==0 use case, please let me know if you insist. > > > + if (last_index < first_index) > > + last_index = ULONG_MAX; > > > > i_mmap_lock_write(mapping); > > if (unlikely(!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))) > > - unmap_mapping_range_tree(&mapping->i_mmap, &details); > > + unmap_mapping_range_tree(&mapping->i_mmap, first_index, > > + last_index, &details); > > i_mmap_unlock_write(mapping); > > } > > > > -- > > 2.31.1 > > > > Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com> Thanks for reviewing.
diff --git a/include/linux/mm.h b/include/linux/mm.h index 73a52aba448f..d1126f731221 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1722,8 +1722,6 @@ extern void user_shm_unlock(size_t, struct ucounts *); */ struct zap_details { struct address_space *check_mapping; /* Check page->mapping if set */ - pgoff_t first_index; /* Lowest page->index to unmap */ - pgoff_t last_index; /* Highest page->index to unmap */ struct page *single_page; /* Locked page to be unmapped */ }; diff --git a/mm/memory.c b/mm/memory.c index 7b095f07c4ef..6bba3b9fef7c 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3321,20 +3321,20 @@ static void unmap_mapping_range_vma(struct vm_area_struct *vma, } static inline void unmap_mapping_range_tree(struct rb_root_cached *root, + pgoff_t first_index, + pgoff_t last_index, struct zap_details *details) { struct vm_area_struct *vma; pgoff_t vba, vea, zba, zea; - vma_interval_tree_foreach(vma, root, - details->first_index, details->last_index) { - + vma_interval_tree_foreach(vma, root, first_index, last_index) { vba = vma->vm_pgoff; vea = vba + vma_pages(vma) - 1; - zba = details->first_index; + zba = first_index; if (zba < vba) zba = vba; - zea = details->last_index; + zea = last_index; if (zea > vea) zea = vea; @@ -3360,18 +3360,21 @@ void unmap_mapping_page(struct page *page) { struct address_space *mapping = page->mapping; struct zap_details details = { }; + pgoff_t first_index, last_index; VM_BUG_ON(!PageLocked(page)); VM_BUG_ON(PageTail(page)); + first_index = page->index; + last_index = page->index + thp_nr_pages(page) - 1; + details.check_mapping = mapping; - details.first_index = page->index; - details.last_index = page->index + thp_nr_pages(page) - 1; details.single_page = page; i_mmap_lock_write(mapping); if (unlikely(!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))) - unmap_mapping_range_tree(&mapping->i_mmap, &details); + unmap_mapping_range_tree(&mapping->i_mmap, first_index, + last_index, &details); i_mmap_unlock_write(mapping); } @@ -3390,17 +3393,17 @@ void unmap_mapping_page(struct page *page) void unmap_mapping_pages(struct address_space *mapping, pgoff_t start, pgoff_t nr, bool even_cows) { + pgoff_t first_index = start, last_index = start + nr - 1; struct zap_details details = { }; details.check_mapping = even_cows ? NULL : mapping; - details.first_index = start; - details.last_index = start + nr - 1; - if (details.last_index < details.first_index) - details.last_index = ULONG_MAX; + if (last_index < first_index) + last_index = ULONG_MAX; i_mmap_lock_write(mapping); if (unlikely(!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root))) - unmap_mapping_range_tree(&mapping->i_mmap, &details); + unmap_mapping_range_tree(&mapping->i_mmap, first_index, + last_index, &details); i_mmap_unlock_write(mapping); }