fs: convert core functions to zero_user_page
It's very common for file systems to need to zero part or all of a page,
the simplist way is just to use kmap_atomic() and memset(). There's
actually a library function in include/linux/highmem.h that does exactly
that, but it's confusingly named memclear_highpage_flush(), which is
descriptive of *how* it does the work rather than what the *purpose* is.
So this patchset renames the function to zero_user_page(), and calls it
from the various places that currently open code it.
This first patch introduces the new function call, and converts all the
core kernel callsites, both the open-coded ones and the old
memclear_highpage_flush() ones. Following this patch is a series of
conversions for each file system individually, per AKPM, and finally a
patch deprecating the old call. The diffstat below shows the entire
patchset.
[akpm@linux-foundation.org: fix a few things]
Signed-off-by: Nate Diller <nate.diller@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/mpage.c b/fs/mpage.c
index fa2441f..0fb914f 100644
--- a/fs/mpage.c
+++ b/fs/mpage.c
@@ -284,11 +284,9 @@
}
if (first_hole != blocks_per_page) {
- char *kaddr = kmap_atomic(page, KM_USER0);
- memset(kaddr + (first_hole << blkbits), 0,
- PAGE_CACHE_SIZE - (first_hole << blkbits));
- flush_dcache_page(page);
- kunmap_atomic(kaddr, KM_USER0);
+ zero_user_page(page, first_hole << blkbits,
+ PAGE_CACHE_SIZE - (first_hole << blkbits),
+ KM_USER0);
if (first_hole == 0) {
SetPageUptodate(page);
unlock_page(page);
@@ -576,14 +574,11 @@
* written out to the file."
*/
unsigned offset = i_size & (PAGE_CACHE_SIZE - 1);
- char *kaddr;
if (page->index > end_index || !offset)
goto confused;
- kaddr = kmap_atomic(page, KM_USER0);
- memset(kaddr + offset, 0, PAGE_CACHE_SIZE - offset);
- flush_dcache_page(page);
- kunmap_atomic(kaddr, KM_USER0);
+ zero_user_page(page, offset, PAGE_CACHE_SIZE - offset,
+ KM_USER0);
}
/*