mm: cleanup descriptions of filler arg

The often-NULL data arg to read_cache_page() and read_mapping_page()
functions is misdescribed as "destination for read data": no, it's the
first arg to the filler function, often struct file * to ->readpage().

Satisfy checkpatch.pl on those filler prototypes, and tidy up the
declarations in linux/pagemap.h.

Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 8e38d4c..cfaaa69 100644 (file)
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -255,26 +255,24 @@ static inline struct page *grab_cache_page(struct address_space *mapping,
 extern struct page * grab_cache_page_nowait(struct address_space *mapping,
                                pgoff_t index);
 extern struct page * read_cache_page_async(struct address_space *mapping,
-                               pgoff_t index, filler_t *filler,
-                               void *data);
+                               pgoff_t index, filler_t *filler, void *data);
 extern struct page * read_cache_page(struct address_space *mapping,
-                               pgoff_t index, filler_t *filler,
-                               void *data);
+                               pgoff_t index, filler_t *filler, void *data);
 extern struct page * read_cache_page_gfp(struct address_space *mapping,
                                pgoff_t index, gfp_t gfp_mask);
 extern int read_cache_pages(struct address_space *mapping,
                struct list_head *pages, filler_t *filler, void *data);
 
 static inline struct page *read_mapping_page_async(
-                                               struct address_space *mapping,
-                                                    pgoff_t index, void *data)
+                               struct address_space *mapping,
+                               pgoff_t index, void *data)
 {
        filler_t *filler = (filler_t *)mapping->a_ops->readpage;
        return read_cache_page_async(mapping, index, filler, data);
 }
 
 static inline struct page *read_mapping_page(struct address_space *mapping,
-                                            pgoff_t index, void *data)
+                               pgoff_t index, void *data)
 {
        filler_t *filler = (filler_t *)mapping->a_ops->readpage;
        return read_cache_page(mapping, index, filler, data);

diff --git a/mm/filemap.c b/mm/filemap.c
index f820e60..2780be4 100644 (file)
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1792,7 +1792,7 @@ EXPORT_SYMBOL(generic_file_readonly_mmap);
 
 static struct page *__read_cache_page(struct address_space *mapping,
                                pgoff_t index,
-                               int (*filler)(void *,struct page*),
+                               int (*filler)(void *, struct page *),
                                void *data,
                                gfp_t gfp)
 {
@@ -1823,7 +1823,7 @@ repeat:
 
 static struct page *do_read_cache_page(struct address_space *mapping,
                                pgoff_t index,
-                               int (*filler)(void *,struct page*),
+                               int (*filler)(void *, struct page *),
                                void *data,
                                gfp_t gfp)
 
@@ -1863,7 +1863,7 @@ out:
  * @mapping:   the page's address_space
  * @index:     the page index
  * @filler:    function to perform the read
- * @data:      destination for read data
+ * @data:      first arg to filler(data, page) function, often left as NULL
  *
  * Same as read_cache_page, but don't wait for page to become unlocked
  * after submitting it to the filler.
@@ -1875,7 +1875,7 @@ out:
  */
 struct page *read_cache_page_async(struct address_space *mapping,
                                pgoff_t index,
-                               int (*filler)(void *,struct page*),
+                               int (*filler)(void *, struct page *),
                                void *data)
 {
        return do_read_cache_page(mapping, index, filler, data, mapping_gfp_mask(mapping));
@@ -1923,7 +1923,7 @@ EXPORT_SYMBOL(read_cache_page_gfp);
  * @mapping:   the page's address_space
  * @index:     the page index
  * @filler:    function to perform the read
- * @data:      destination for read data
+ * @data:      first arg to filler(data, page) function, often left as NULL
  *
  * Read into the page cache. If a page already exists, and PageUptodate() is
  * not set, try to fill the page then wait for it to become unlocked.
@@ -1932,7 +1932,7 @@ EXPORT_SYMBOL(read_cache_page_gfp);
  */
 struct page *read_cache_page(struct address_space *mapping,
                                pgoff_t index,
-                               int (*filler)(void *,struct page*),
+                               int (*filler)(void *, struct page *),
                                void *data)
 {
        return wait_on_page_read(read_cache_page_async(mapping, index, filler, data));