Merge tag 'folio-5.19' of git://git.infradead.org/users/willy/pagecache

Pull page cache updates from Matthew Wilcox:

 - Appoint myself page cache maintainer

 - Fix how scsicam uses the page cache

 - Use the memalloc_nofs_save() API to replace AOP_FLAG_NOFS

 - Remove the AOP flags entirely

 - Remove pagecache_write_begin() and pagecache_write_end()

 - Documentation updates

 - Convert several address_space operations to use folios:
     - is_dirty_writeback
     - readpage becomes read_folio
     - releasepage becomes release_folio
     - freepage becomes free_folio

 - Change filler_t to require a struct file pointer be the first
   argument like ->read_folio

* tag 'folio-5.19' of git://git.infradead.org/users/willy/pagecache: (107 commits)
  nilfs2: Fix some kernel-doc comments
  Appoint myself page cache maintainer
  fs: Remove aops->freepage
  secretmem: Convert to free_folio
  nfs: Convert to free_folio
  orangefs: Convert to free_folio
  fs: Add free_folio address space operation
  fs: Convert drop_buffers() to use a folio
  fs: Change try_to_free_buffers() to take a folio
  jbd2: Convert release_buffer_page() to use a folio
  jbd2: Convert jbd2_journal_try_to_free_buffers to take a folio
  reiserfs: Convert release_buffer_page() to use a folio
  fs: Remove last vestiges of releasepage
  ubifs: Convert to release_folio
  reiserfs: Convert to release_folio
  orangefs: Convert to release_folio
  ocfs2: Convert to release_folio
  nilfs2: Remove comment about releasepage
  nfs: Convert to release_folio
  jfs: Convert to release_folio
  ...

1 files changed, 63 insertions, 15 deletions

diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 6165283bdb6f..ce96866fbec4 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -492,7 +492,7 @@ static inline gfp_t readahead_gfp_mask(struct address_space *x)
 	return mapping_gfp_mask(x) | __GFP_NORETRY | __GFP_NOWARN;
 }
 
-typedef int filler_t(void *, struct page *);
+typedef int filler_t(struct file *, struct folio *);
 
 pgoff_t page_cache_next_miss(struct address_space *mapping,
 			     pgoff_t index, unsigned long max_scan);
@@ -735,7 +735,7 @@ static inline unsigned find_get_pages_tag(struct address_space *mapping,
 }
 
 struct page *grab_cache_page_write_begin(struct address_space *mapping,
-			pgoff_t index, unsigned flags);
+			pgoff_t index);
 
 /*
  * Returns locked page at given index in given cache, creating it if needed.
@@ -747,9 +747,9 @@ static inline struct page *grab_cache_page(struct address_space *mapping,
 }
 
 struct folio *read_cache_folio(struct address_space *, pgoff_t index,
-		filler_t *filler, void *data);
+		filler_t *filler, struct file *file);
 struct page *read_cache_page(struct address_space *, pgoff_t index,
-		filler_t *filler, void *data);
+		filler_t *filler, struct file *file);
 extern struct page * read_cache_page_gfp(struct address_space *mapping,
 				pgoff_t index, gfp_t gfp_mask);
 
@@ -888,6 +888,18 @@ bool __folio_lock_or_retry(struct folio *folio, struct mm_struct *mm,
 void unlock_page(struct page *page);
 void folio_unlock(struct folio *folio);
 
+/**
+ * folio_trylock() - Attempt to lock a folio.
+ * @folio: The folio to attempt to lock.
+ *
+ * Sometimes it is undesirable to wait for a folio to be unlocked (eg
+ * when the locks are being taken in the wrong order, or if making
+ * progress through a batch of folios is more important than processing
+ * them in order).  Usually folio_lock() is the correct function to call.
+ *
+ * Context: Any context.
+ * Return: Whether the lock was successfully acquired.
+ */
 static inline bool folio_trylock(struct folio *folio)
 {
 	return likely(!test_and_set_bit_lock(PG_locked, folio_flags(folio, 0)));
@@ -901,6 +913,28 @@ static inline int trylock_page(struct page *page)
 	return folio_trylock(page_folio(page));
 }
 
+/**
+ * folio_lock() - Lock this folio.
+ * @folio: The folio to lock.
+ *
+ * The folio lock protects against many things, probably more than it
+ * should.  It is primarily held while a folio is being brought uptodate,
+ * either from its backing file or from swap.  It is also held while a
+ * folio is being truncated from its address_space, so holding the lock
+ * is sufficient to keep folio->mapping stable.
+ *
+ * The folio lock is also held while write() is modifying the page to
+ * provide POSIX atomicity guarantees (as long as the write does not
+ * cross a page boundary).  Other modifications to the data in the folio
+ * do not hold the folio lock and can race with writes, eg DMA and stores
+ * to mapped pages.
+ *
+ * Context: May sleep.  If you need to acquire the locks of two or
+ * more folios, they must be in order of ascending index, if they are
+ * in the same address_space.  If they are in different address_spaces,
+ * acquire the lock of the folio which belongs to the address_space which
+ * has the lowest address in memory first.
+ */
 static inline void folio_lock(struct folio *folio)
 {
 	might_sleep();
@@ -908,8 +942,16 @@ static inline void folio_lock(struct folio *folio)
 		__folio_lock(folio);
 }
 
-/*
- * lock_page may only be called if we have the page's inode pinned.
+/**
+ * lock_page() - Lock the folio containing this page.
+ * @page: The page to lock.
+ *
+ * See folio_lock() for a description of what the lock protects.
+ * This is a legacy function and new code should probably use folio_lock()
+ * instead.
+ *
+ * Context: May sleep.  Pages in the same folio share a lock, so do not
+ * attempt to lock two pages which share a folio.
  */
 static inline void lock_page(struct page *page)
 {
@@ -921,6 +963,16 @@ static inline void lock_page(struct page *page)
 		__folio_lock(folio);
 }
 
+/**
+ * folio_lock_killable() - Lock this folio, interruptible by a fatal signal.
+ * @folio: The folio to lock.
+ *
+ * Attempts to lock the folio, like folio_lock(), except that the sleep
+ * to acquire the lock is interruptible by a fatal signal.
+ *
+ * Context: May sleep; see folio_lock().
+ * Return: 0 if the lock was acquired; -EINTR if a fatal signal was received.
+ */
 static inline int folio_lock_killable(struct folio *folio)
 {
 	might_sleep();
@@ -967,8 +1019,8 @@ int folio_wait_bit_killable(struct folio *folio, int bit_nr);
  * Wait for a folio to be unlocked.
  *
  * This must be called with the caller "holding" the folio,
- * ie with increased "page->count" so that the folio won't
- * go away during the wait..
+ * ie with increased folio reference count so that the folio won't
+ * go away during the wait.
  */
 static inline void folio_wait_locked(struct folio *folio)
 {
@@ -1015,10 +1067,6 @@ static inline void folio_cancel_dirty(struct folio *folio)
 	if (folio_test_dirty(folio))
 		__folio_cancel_dirty(folio);
 }
-static inline void cancel_dirty_page(struct page *page)
-{
-	folio_cancel_dirty(page_folio(page));
-}
 bool folio_clear_dirty_for_io(struct folio *folio);
 bool clear_page_dirty_for_io(struct page *page);
 void folio_invalidate(struct folio *folio, size_t offset, size_t length);
@@ -1191,7 +1239,7 @@ void page_cache_sync_readahead(struct address_space *mapping,
  * @mapping: address_space which holds the pagecache and I/O vectors
  * @ra: file_ra_state which holds the readahead state
  * @file: Used by the filesystem for authentication.
- * @page: The page at @index which triggered the readahead call.
+ * @folio: The folio at @index which triggered the readahead call.
  * @index: Index of first page to be read.
  * @req_count: Total number of pages being read by the caller.
  *
@@ -1203,10 +1251,10 @@ void page_cache_sync_readahead(struct address_space *mapping,
 static inline
 void page_cache_async_readahead(struct address_space *mapping,
 		struct file_ra_state *ra, struct file *file,
-		struct page *page, pgoff_t index, unsigned long req_count)
+		struct folio *folio, pgoff_t index, unsigned long req_count)
 {
 	DEFINE_READAHEAD(ractl, file, ra, mapping, index);
-	page_cache_async_ra(&ractl, page_folio(page), req_count);
+	page_cache_async_ra(&ractl, folio, req_count);
 }
 
 static inline struct folio *__readahead_folio(struct readahead_control *ractl)