2.6.26-stable review patch. If anyone has any objections, please let us know.

------------------

From: Ian Campbell

commit d847471d063663b9f36927d265c66a270c0cfaab upstream

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

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

commit 14fcc23fdc78e9d32372553ccf21758a9bd56fa1
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
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
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
Signed-off-by: Greg Kroah-Hartman

---
drivers/video/fb_defio.c | 19 +++++++++++++++++++
drivers/video/fbmem.c | 4 ++++
include/linux/fb.h | 3 +++
3 files changed, 26 insertions(+)

--- a/drivers/video/fb_defio.c
+++ b/drivers/video/fb_defio.c
@@ -114,6 +114,17 @@ static struct vm_operations_struct fb_de
.page_mkwrite = fb_deferred_io_mkwrite,
};

+static int fb_deferred_io_set_page_dirty(struct page *page)
+{
+ if (!PageDirty(page))
+ SetPageDirty(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
}
EXPORT_SYMBOL_GPL(fb_deferred_io_init);

+void fb_deferred_io_open(struct fb_info *info,
+ struct inode *inode,
+ struct file *file)
+{
+ file->f_mapping->a_ops = &fb_deferred_io_aops;
+}
+EXPORT_SYMBOL_GPL(fb_deferred_io_open);
+
void fb_deferred_io_cleanup(struct fb_info *info)
{
void *screen_base = (void __force *) info->screen_base;
--- a/drivers/video/fbmem.c
+++ b/drivers/video/fbmem.c
@@ -1340,6 +1340,10 @@ fb_open(struct inode *inode, struct file
if (res)
module_put(info->fbops->owner);
}
+#ifdef CONFIG_FB_DEFERRED_IO
+ if (info->fbdefio)
+ fb_deferred_io_open(info, inode, file);
+#endif
return res;
}

--- a/include/linux/fb.h
+++ b/include/linux/fb.h
@@ -973,6 +973,9 @@ static inline void __fb_pad_aligned_buff

/* 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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