Commit d847471d authored by Ian Campbell's avatar Ian Campbell Committed by Linus Torvalds

fbdefio: add set_page_dirty handler to deferred IO FB

Fixes kernel BUG at lib/radix-tree.c:473.

Previously the handler was incidentally provided by tmpfs but this was
removed with:

  commit 14fcc23f
  Author: Hugh Dickins <>
  Date:   Mon Jul 28 15:46:19 2008 -0700

    tmpfs: fix kernel BUG in shmem_delete_inode

relying on this behaviour was incorrect in any case and the BUG also
appeared when the device node was on an ext3 filesystem.

v2: override a_ops at open() time rather than mmap() time to minimise
races per AKPM's concerns.
Signed-off-by: Ian Campbell's avatarIan Campbell <>
Cc: Jaya Kumar <>
Cc: Nick Piggin <>
Cc: Peter Zijlstra <>
Cc: Hugh Dickins <>
Cc: Johannes Weiner <>
Cc: Jeremy Fitzhardinge <>
Cc: Kel Modderman <>
Cc: Markus Armbruster <>
Cc: Krzysztof Helt <>
Cc: <> [14fcc23f is in and]
Signed-off-by: default avatarAndrew Morton <>
Signed-off-by: default avatarLinus Torvalds <>
parent b42f9317
......@@ -114,6 +114,17 @@ static struct vm_operations_struct fb_deferred_io_vm_ops = {
.page_mkwrite = fb_deferred_io_mkwrite,
static int fb_deferred_io_set_page_dirty(struct page *page)
if (!PageDirty(page))
return 0;
static const struct address_space_operations fb_deferred_io_aops = {
.set_page_dirty = fb_deferred_io_set_page_dirty,
static int fb_deferred_io_mmap(struct fb_info *info, struct vm_area_struct *vma)
vma->vm_ops = &fb_deferred_io_vm_ops;
......@@ -163,6 +174,14 @@ void fb_deferred_io_init(struct fb_info *info)
void fb_deferred_io_open(struct fb_info *info,
struct inode *inode,
struct file *file)
file->f_mapping->a_ops = &fb_deferred_io_aops;
void fb_deferred_io_cleanup(struct fb_info *info)
void *screen_base = (void __force *) info->screen_base;
......@@ -1344,6 +1344,10 @@ fb_open(struct inode *inode, struct file *file)
if (res)
if (info->fbdefio)
fb_deferred_io_open(info, inode, file);
return res;
......@@ -976,6 +976,9 @@ static inline void __fb_pad_aligned_buffer(u8 *dst, u32 d_pitch,
/* drivers/video/fb_defio.c */
extern void fb_deferred_io_init(struct fb_info *info);
extern void fb_deferred_io_open(struct fb_info *info,
struct inode *inode,
struct file *file);
extern void fb_deferred_io_cleanup(struct fb_info *info);
extern int fb_deferred_io_fsync(struct file *file, struct dentry *dentry,
int datasync);
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