From: Andrew Morton <akpm@osdl.org>
empty_zero_page is an arch-specific thing. Alpha does not implement it. Use
ZERO_PAGE().
Only mips seems to actually use the `vaddr' arg to ZERO_PAGE. Randomly pick
zero for it.
Generally, this seems to be a fairly weird way of handling holes. It would be
much more straightforward to simply do a clear_user() right there and be done
with it.
Does a flush_dcache_page() on the zero page work correctly on all
architectures?
Why are we testing mapping_writably_mapped() there? flush_dcache_page()
should be able to handle that?
Why are we running flush_dcache_page() at all? That's only supposed to be
used when the kernel modifies a possibly-mmapped pagecache page by hand. But
here we're _reading_ from the page which ->direct_access() returned.
Why isn't __inode_direct_access() in a generic file?
Please fix up coding style in fs/ext2/xip.c:
int
ext2_clear_xip_target(struct inode *inode, int block) {
Who made that up? It should be
int ext2_clear_xip_target(struct inode *inode, int block)
{
Please clean up ext2_get_xip_page() - it's quite nutty.
The ->direct_access() API seems poorly designed.
a) It returns an unsigned long. What if an architecture supports highmem
and wants to return data in highmem pages? For this, ->direct_access()
should return a pageframe.
b) But then again, ->get_xip_page() is supposed to return the
directly-addressed memory as a pageframe! This means that the architecture
can only perform xip access to memory which is described in its pageframe
array.
This seems weird. What if there's some random piece of ROM somewhere in
the memory map which isn't inside the mem_map[] arena? In this case we
want ->get_xip_page() to return a kernel-virtual address.
Cc: Carsten Otte <cotte@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
mm/filemap_xip.c | 2 +-
1 files changed, 1 insertion(+), 1 deletion(-)
diff -puN mm/filemap_xip.c~xip-empty_zero_page-build-fix mm/filemap_xip.c
--- devel/mm/filemap_xip.c~xip-empty_zero_page-build-fix 2005-07-02 00:53:20.000000000 -0700
+++ devel-akpm/mm/filemap_xip.c 2005-07-02 00:57:02.000000000 -0700
@@ -68,7 +68,7 @@ do_xip_mapping_read(struct address_space
if (unlikely(IS_ERR(page))) {
if (PTR_ERR(page) == -ENODATA) {
/* sparse */
- page = virt_to_page(empty_zero_page);
+ page = ZERO_PAGE(0);
} else {
desc->error = PTR_ERR(page);
goto out;
_