From: Hugh Dickins <hugh@veritas.com>
Very minor adjustments to shmem_getpage return path: I now prefer it to return
NULL and let do_shmem_file_read use ZERO_PAGE(0) in that case; and we don't
need a local majmin variable, do_no_page initializes *type to VM_FAULT_MINOR
already.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/mm/shmem.c | 26 ++++++++++++--------------
1 files changed, 12 insertions(+), 14 deletions(-)
diff -puN mm/shmem.c~shmem-rework-majmin-and-zero_page mm/shmem.c
--- 25/mm/shmem.c~shmem-rework-majmin-and-zero_page 2004-09-05 21:24:50.827778112 -0700
+++ 25-akpm/mm/shmem.c 2004-09-05 21:24:50.833777200 -0700
@@ -885,7 +885,7 @@ static int shmem_getpage(struct inode *i
struct page *swappage;
swp_entry_t *entry;
swp_entry_t swap;
- int error, majmin = VM_FAULT_MINOR;
+ int error;
if (idx >= SHMEM_MAX_INDEX)
return -EFBIG;
@@ -923,9 +923,10 @@ repeat:
shmem_swp_unmap(entry);
spin_unlock(&info->lock);
/* here we actually do the io */
- if (majmin == VM_FAULT_MINOR && type)
+ if (type && *type == VM_FAULT_MINOR) {
inc_page_state(pgmajfault);
- majmin = VM_FAULT_MAJOR;
+ *type = VM_FAULT_MAJOR;
+ }
swappage = shmem_swapin(info, swap, idx);
if (!swappage) {
spin_lock(&info->lock);
@@ -1077,15 +1078,10 @@ repeat:
SetPageUptodate(filepage);
}
done:
- if (!*pagep) {
- if (filepage) {
- unlock_page(filepage);
- *pagep = filepage;
- } else
- *pagep = ZERO_PAGE(0);
+ if (*pagep != filepage) {
+ unlock_page(filepage);
+ *pagep = filepage;
}
- if (type)
- *type = majmin;
return 0;
failed:
@@ -1442,13 +1438,14 @@ static void do_shmem_file_read(struct fi
if (index == end_index) {
nr = i_size & ~PAGE_CACHE_MASK;
if (nr <= offset) {
- page_cache_release(page);
+ if (page)
+ page_cache_release(page);
break;
}
}
nr -= offset;
- if (page != ZERO_PAGE(0)) {
+ if (page) {
/*
* If users can be writing to this page using arbitrary
* virtual addresses, take care about potential aliasing
@@ -1461,7 +1458,8 @@ static void do_shmem_file_read(struct fi
*/
if (!offset)
mark_page_accessed(page);
- }
+ } else
+ page = ZERO_PAGE(0);
/*
* Ok, we have the page, and it's up-to-date, so
_