[PATCH v4 08/36] fs: Do not update nr_thps for large page mappings

[Matthew Wilcox]

From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>

The nr_thps counter is to support large pages in the page cache
when the filesystem does not support writing large pages.  Eventually
it will be removed, but we should still support filesystems which
do not understand large pages yet.  Move the nr_thp manipulation
functions to filemap.h since they're page-cache specific.

Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
---
 include/linux/fs.h      | 27 ---------------------------
 include/linux/pagemap.h | 29 +++++++++++++++++++++++++++++
 2 files changed, 29 insertions(+), 27 deletions(-)

diff --git a/include/linux/fs.h b/include/linux/fs.h
index 777783c8760b..1ab65898bd96 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2830,33 +2830,6 @@ static inline errseq_t filemap_sample_wb_err(struct address_space *mapping)
 	return errseq_sample(&mapping->wb_err);
 }
 
-static inline int filemap_nr_thps(struct address_space *mapping)
-{
-#ifdef CONFIG_READ_ONLY_THP_FOR_FS
-	return atomic_read(&mapping->nr_thps);
-#else
-	return 0;
-#endif
-}
-
-static inline void filemap_nr_thps_inc(struct address_space *mapping)
-{
-#ifdef CONFIG_READ_ONLY_THP_FOR_FS
-	atomic_inc(&mapping->nr_thps);
-#else
-	WARN_ON_ONCE(1);
-#endif
-}
-
-static inline void filemap_nr_thps_dec(struct address_space *mapping)
-{
-#ifdef CONFIG_READ_ONLY_THP_FOR_FS
-	atomic_dec(&mapping->nr_thps);
-#else
-	WARN_ON_ONCE(1);
-#endif
-}
-
 extern int vfs_fsync_range(struct file *file, loff_t start, loff_t end,
 			   int datasync);
 extern int vfs_fsync(struct file *file, int datasync);
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index c6db74b5e62f..cacd5a30cb9d 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -121,6 +121,35 @@ static inline bool mapping_large_pages(struct address_space *mapping)
 	return mapping->host->i_sb->s_type->fs_flags & FS_LARGE_PAGES;
 }
 
+static inline int filemap_nr_thps(struct address_space *mapping)
+{
+#ifdef CONFIG_READ_ONLY_THP_FOR_FS
+	return atomic_read(&mapping->nr_thps);
+#else
+	return 0;
+#endif
+}
+
+static inline void filemap_nr_thps_inc(struct address_space *mapping)
+{
+#ifdef CONFIG_READ_ONLY_THP_FOR_FS
+	if (!mapping_large_pages(mapping))
+		atomic_inc(&mapping->nr_thps);
+#else
+	WARN_ON_ONCE(1);
+#endif
+}
+
+static inline void filemap_nr_thps_dec(struct address_space *mapping)
+{
+#ifdef CONFIG_READ_ONLY_THP_FOR_FS
+	if (!mapping_large_pages(mapping))
+		atomic_dec(&mapping->nr_thps);
+#else
+	WARN_ON_ONCE(1);
+#endif
+}
+
 void release_pages(struct page **pages, int nr);
 
 /*
-- 
2.26.2