mm: write iovec cleanup

Hide some of the open-coded nr_segs tests into the iovec helpers.  This is all
to simplify generic_file_buffered_write, because that gets more complex in the
next patch.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Nick Piggin
2007-10-16 01:24:58 -07:00
committed by Linus Torvalds
parent eb2be18931
commit 4a9e5ef1f4
3 changed files with 77 additions and 96 deletions

View File

@@ -15,7 +15,6 @@
#include <linux/rmap.h>
#include <linux/sched.h>
#include <asm/tlbflush.h>
#include "filemap.h"
/*
* We do use our own empty page to avoid interference with other users
@@ -288,6 +287,7 @@ __xip_file_write(struct file *filp, const char __user *buf,
unsigned long index;
unsigned long offset;
size_t copied;
char *kaddr;
offset = (pos & (PAGE_CACHE_SIZE -1)); /* Within page */
index = pos >> PAGE_CACHE_SHIFT;
@@ -295,14 +295,6 @@ __xip_file_write(struct file *filp, const char __user *buf,
if (bytes > count)
bytes = count;
/*
* Bring in the user page that we will copy from _first_.
* Otherwise there's a nasty deadlock on copying from the
* same page as we're writing to, without it being marked
* up-to-date.
*/
fault_in_pages_readable(buf, bytes);
page = a_ops->get_xip_page(mapping,
index*(PAGE_SIZE/512), 0);
if (IS_ERR(page) && (PTR_ERR(page) == -ENODATA)) {
@@ -319,8 +311,13 @@ __xip_file_write(struct file *filp, const char __user *buf,
break;
}
copied = filemap_copy_from_user(page, offset, buf, bytes);
fault_in_pages_readable(buf, bytes);
kaddr = kmap_atomic(page, KM_USER0);
copied = bytes -
__copy_from_user_inatomic_nocache(kaddr, buf, bytes);
kunmap_atomic(kaddr, KM_USER0);
flush_dcache_page(page);
if (likely(copied > 0)) {
status = copied;