1 files changed, 50 insertions, 6 deletions

diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 1a0c646eb6ff..422bdf9f4e76 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -84,7 +84,7 @@ enum mapping_flags {
 	AS_EXITING	= 4, 	/* final truncate in progress */
 	/* writeback related tags are not used */
 	AS_NO_WRITEBACK_TAGS = 5,
-	AS_THP_SUPPORT = 6,	/* THPs supported */
+	AS_LARGE_FOLIO_SUPPORT = 6,
 };
 
 /**
@@ -176,9 +176,25 @@ static inline void mapping_set_gfp_mask(struct address_space *m, gfp_t mask)
 	m->gfp_mask = mask;
 }
 
-static inline bool mapping_thp_support(struct address_space *mapping)
+/**
+ * mapping_set_large_folios() - Indicate the file supports large folios.
+ * @mapping: The file.
+ *
+ * The filesystem should call this function in its inode constructor to
+ * indicate that the VFS can use large folios to cache the contents of
+ * the file.
+ *
+ * Context: This should not be called while the inode is active as it
+ * is non-atomic.
+ */
+static inline void mapping_set_large_folios(struct address_space *mapping)
 {
-	return test_bit(AS_THP_SUPPORT, &mapping->flags);
+	__set_bit(AS_LARGE_FOLIO_SUPPORT, &mapping->flags);
+}
+
+static inline bool mapping_large_folio_support(struct address_space *mapping)
+{
+	return test_bit(AS_LARGE_FOLIO_SUPPORT, &mapping->flags);
 }
 
 static inline int filemap_nr_thps(struct address_space *mapping)
@@ -193,7 +209,7 @@ static inline int filemap_nr_thps(struct address_space *mapping)
 static inline void filemap_nr_thps_inc(struct address_space *mapping)
 {
 #ifdef CONFIG_READ_ONLY_THP_FOR_FS
-	if (!mapping_thp_support(mapping))
+	if (!mapping_large_folio_support(mapping))
 		atomic_inc(&mapping->nr_thps);
 #else
 	WARN_ON_ONCE(1);
@@ -203,7 +219,7 @@ static inline void filemap_nr_thps_inc(struct address_space *mapping)
 static inline void filemap_nr_thps_dec(struct address_space *mapping)
 {
 #ifdef CONFIG_READ_ONLY_THP_FOR_FS
-	if (!mapping_thp_support(mapping))
+	if (!mapping_large_folio_support(mapping))
 		atomic_dec(&mapping->nr_thps);
 #else
 	WARN_ON_ONCE(1);
@@ -269,7 +285,6 @@ static inline struct inode *folio_inode(struct folio *folio)
 
 static inline bool page_cache_add_speculative(struct page *page, int count)
 {
-	VM_BUG_ON_PAGE(PageTail(page), page);
 	return folio_ref_try_add_rcu((struct folio *)page, count);
 }
 
@@ -947,6 +962,35 @@ static inline int add_to_page_cache(struct page *page,
 int __filemap_add_folio(struct address_space *mapping, struct folio *folio,
 		pgoff_t index, gfp_t gfp, void **shadowp);
 
+bool filemap_range_has_writeback(struct address_space *mapping,
+				 loff_t start_byte, loff_t end_byte);
+
+/**
+ * filemap_range_needs_writeback - check if range potentially needs writeback
+ * @mapping:           address space within which to check
+ * @start_byte:        offset in bytes where the range starts
+ * @end_byte:          offset in bytes where the range ends (inclusive)
+ *
+ * Find at least one page in the range supplied, usually used to check if
+ * direct writing in this range will trigger a writeback. Used by O_DIRECT
+ * read/write with IOCB_NOWAIT, to see if the caller needs to do
+ * filemap_write_and_wait_range() before proceeding.
+ *
+ * Return: %true if the caller should do filemap_write_and_wait_range() before
+ * doing O_DIRECT to a page in this range, %false otherwise.
+ */
+static inline bool filemap_range_needs_writeback(struct address_space *mapping,
+						 loff_t start_byte,
+						 loff_t end_byte)
+{
+	if (!mapping->nrpages)
+		return false;
+	if (!mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) &&
+	    !mapping_tagged(mapping, PAGECACHE_TAG_WRITEBACK))
+		return false;
+	return filemap_range_has_writeback(mapping, start_byte, end_byte);
+}
+
 /**
  * struct readahead_control - Describes a readahead request.
  *