2006-12-26 17:12:03

by Dimitri Gorokhovik

Subject: [PATCH 1/1 2.6.20-rc2] MM: ramfs breaks without CONFIG_BLOCK

From: Dimitri Gorokhovik <[email protected]>

ramfs doesn't provide the .set_dirty_page a_op, and when the BLOCK
layer is not configured in, 'set_page_dirty' makes a call via a NULL
pointer.

Signed-off-by: Dimitri Gorokhovik <[email protected]>

---

--- linux-2.6.20-rc2-orig/mm/page-writeback.c 2006-12-26
15:12:21.000000000 +0100
+++ linux-2.6.20-rc2/mm/page-writeback.c 2006-12-26 18:32:26.000000000
+0100
@@ -800,8 +800,8 @@ int redirty_page_for_writepage(struct wr
EXPORT_SYMBOL(redirty_page_for_writepage);

/*
- * If the mapping doesn't provide a set_page_dirty a_op, then
- * just fall through and assume that it wants buffer_heads.
+ * If the mapping doesn't provide a set_page_dirty a_op, and the BLOCK
layer is
+ * available, just fall through and assume that it wants buffer_heads.
*/
int fastcall set_page_dirty(struct page *page)
{
@@ -812,8 +812,12 @@ int fastcall set_page_dirty(struct page
#ifdef CONFIG_BLOCK
if (!spd)
spd = __set_page_dirty_buffers;
-#endif
return (*spd)(page);
+#else
+ if (spd)
+ return (*spd)(page);
+#endif
+
}
if (!PageDirty(page)) {
if (!TestSetPageDirty(page))

2006-12-27 09:04:05

by Andrew Morton

Subject: Re: [PATCH 1/1 2.6.20-rc2] MM: ramfs breaks without CONFIG_BLOCK

On Tue, 26 Dec 2006 18:09:47 +0100
[email protected] wrote:

> From: Dimitri Gorokhovik <[email protected]>
>
> ramfs doesn't provide the .set_dirty_page a_op, and when the BLOCK
> layer is not configured in, 'set_page_dirty' makes a call via a NULL
> pointer.

OK. But I think it'd be better to fill in the address_space_operations:


From: Dimitri Gorokhovik <[email protected]>

ramfs doesn't provide the .set_dirty_page a_op, and when the BLOCK layer is
not configured in, 'set_page_dirty' makes a call via a NULL pointer.

Signed-off-by: Dimitri Gorokhovik <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
---

fs/ramfs/file-mmu.c | 4 +++-
fs/ramfs/file-nommu.c | 4 +++-
2 files changed, 6 insertions(+), 2 deletions(-)

diff -puN fs/ramfs/file-mmu.c~mm-ramfs-breaks-without-config_block fs/ramfs/file-mmu.c
--- a/fs/ramfs/file-mmu.c~mm-ramfs-breaks-without-config_block
+++ a/fs/ramfs/file-mmu.c
@@ -25,11 +25,13 @@
*/

#include <linux/fs.h>
+#include <linux/mm.h>

const struct address_space_operations ramfs_aops = {
.readpage = simple_readpage,
.prepare_write = simple_prepare_write,
- .commit_write = simple_commit_write
+ .commit_write = simple_commit_write,
+ .set_page_dirty = __set_page_dirty_nobuffers,
};

const struct file_operations ramfs_file_operations = {
diff -puN fs/ramfs/file-nommu.c~mm-ramfs-breaks-without-config_block fs/ramfs/file-nommu.c
--- a/fs/ramfs/file-nommu.c~mm-ramfs-breaks-without-config_block
+++ a/fs/ramfs/file-nommu.c
@@ -11,6 +11,7 @@

#include <linux/module.h>
#include <linux/fs.h>
+#include <linux/mm.h>
#include <linux/pagemap.h>
#include <linux/highmem.h>
#include <linux/init.h>
@@ -30,7 +31,8 @@ static int ramfs_nommu_setattr(struct de
const struct address_space_operations ramfs_aops = {
.readpage = simple_readpage,
.prepare_write = simple_prepare_write,
- .commit_write = simple_commit_write
+ .commit_write = simple_commit_write,
+ .set_page_dirty = __set_page_dirty_nobuffers,
};

const struct file_operations ramfs_file_operations = {
_