Commit 9595d769 authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle)
Browse files

mm/rmap: Turn page_lock_anon_vma_read() into folio_lock_anon_vma_read() 



Add back page_lock_anon_vma_read() as a wrapper.  This saves a few calls
to compound_head().  If any callers were passing a tail page before,
this would have failed to lock the anon VMA as page->mapping is not
valid for tail pages.

Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
parent c8423186

include/linux/rmap.h

+1 −0
Original line number Diff line number Diff line
@@ -267,6 +267,7 @@ void remove_migration_ptes(struct folio *src, struct folio *dst, bool locked); 
 * Called by memory-failure.c to kill processes.

 */

struct anon_vma *page_lock_anon_vma_read(struct page *page);

struct anon_vma *folio_lock_anon_vma_read(struct folio *folio);

void page_unlock_anon_vma_read(struct anon_vma *anon_vma);

int page_mapped_in_vma(struct page *page, struct vm_area_struct *vma);

mm/folio-compat.c

+7 −0
Original line number Diff line number Diff line
@@ -164,3 +164,10 @@ void putback_lru_page(struct page *page) 
{

	folio_putback_lru(page_folio(page));

}



#ifdef CONFIG_MMU

struct anon_vma *page_lock_anon_vma_read(struct page *page)

{

	return folio_lock_anon_vma_read(page_folio(page));

}

#endif

mm/memory-failure.c

+2 −1
Original line number Diff line number Diff line
@@ -487,12 +487,13 @@ static struct task_struct *task_early_kill(struct task_struct *tsk, 
static void collect_procs_anon(struct page *page, struct list_head *to_kill,

				int force_early)

{

	struct folio *folio = page_folio(page);

	struct vm_area_struct *vma;

	struct task_struct *tsk;

	struct anon_vma *av;

	pgoff_t pgoff;



	av = page_lock_anon_vma_read(page);

	av = folio_lock_anon_vma_read(folio);

	if (av == NULL)	/* Not actually mapped anymore */

		return;

mm/rmap.c

+6 −6
Original line number Diff line number Diff line
@@ -526,28 +526,28 @@ struct anon_vma *page_get_anon_vma(struct page *page) 
 * atomic op -- the trylock. If we fail the trylock, we fall back to getting a

 * reference like with page_get_anon_vma() and then block on the mutex.

 */

struct anon_vma *page_lock_anon_vma_read(struct page *page)

struct anon_vma *folio_lock_anon_vma_read(struct folio *folio)

{

	struct anon_vma *anon_vma = NULL;

	struct anon_vma *root_anon_vma;

	unsigned long anon_mapping;



	rcu_read_lock();

	anon_mapping = (unsigned long)READ_ONCE(page->mapping);

	anon_mapping = (unsigned long)READ_ONCE(folio->mapping);

	if ((anon_mapping & PAGE_MAPPING_FLAGS) != PAGE_MAPPING_ANON)

		goto out;

	if (!page_mapped(page))

	if (!folio_mapped(folio))

		goto out;



	anon_vma = (struct anon_vma *) (anon_mapping - PAGE_MAPPING_ANON);

	root_anon_vma = READ_ONCE(anon_vma->root);

	if (down_read_trylock(&root_anon_vma->rwsem)) {

		/*

		 * If the page is still mapped, then this anon_vma is still

		 * If the folio is still mapped, then this anon_vma is still

		 * its anon_vma, and holding the mutex ensures that it will

		 * not go away, see anon_vma_free().

		 */

		if (!page_mapped(page)) {

		if (!folio_mapped(folio)) {

			up_read(&root_anon_vma->rwsem);

			anon_vma = NULL;

		}
@@ -560,7 +560,7 @@ struct anon_vma *page_lock_anon_vma_read(struct page *page) 
		goto out;

	}



	if (!page_mapped(page)) {

	if (!folio_mapped(folio)) {

		rcu_read_unlock();

		put_anon_vma(anon_vma);

		return NULL;