[PATCH] mm: schedule find_trylock_page() removal
find_trylock_page() is an odd interface in that it doesn't take a reference
like the others. Now that XFS no longer uses it, and its last remaining
caller actually wants an elevated refcount, opencode that callsite and
schedule find_trylock_page() for removal.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Acked-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt
index 495858b..a92b10b 100644
--- a/Documentation/feature-removal-schedule.txt
+++ b/Documentation/feature-removal-schedule.txt
@@ -241,3 +241,15 @@
Who: Greg Kroah-Hartman <gregkh@suse.de>
---------------------------
+
+What: find_trylock_page
+When: January 2007
+Why: The interface no longer has any callers left in the kernel. It
+ is an odd interface (compared with other find_*_page functions), in
+ that it does not take a refcount to the page, only the page lock.
+ It should be replaced with find_get_page or find_lock_page if possible.
+ This feature removal can be reevaluated if users of the interface
+ cannot cleanly use something else.
+Who: Nick Piggin <npiggin@suse.de>
+
+---------------------------
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 839f0b3..9539efd 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -72,8 +72,8 @@
unsigned long index);
extern struct page * find_lock_page(struct address_space *mapping,
unsigned long index);
-extern struct page * find_trylock_page(struct address_space *mapping,
- unsigned long index);
+extern __deprecated_for_modules struct page * find_trylock_page(
+ struct address_space *mapping, unsigned long index);
extern struct page * find_or_create_page(struct address_space *mapping,
unsigned long index, gfp_t gfp_mask);
unsigned find_get_pages(struct address_space *mapping, pgoff_t start,
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 39aa9d1..e5fd538 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -397,18 +397,24 @@
p = swap_info_get(entry);
if (p) {
- if (swap_entry_free(p, swp_offset(entry)) == 1)
- page = find_trylock_page(&swapper_space, entry.val);
+ if (swap_entry_free(p, swp_offset(entry)) == 1) {
+ page = find_get_page(&swapper_space, entry.val);
+ if (page && unlikely(TestSetPageLocked(page))) {
+ page_cache_release(page);
+ page = NULL;
+ }
+ }
spin_unlock(&swap_lock);
}
if (page) {
int one_user;
BUG_ON(PagePrivate(page));
- page_cache_get(page);
one_user = (page_count(page) == 2);
/* Only cache user (+us), or swap space full? Free it! */
- if (!PageWriteback(page) && (one_user || vm_swap_full())) {
+ /* Also recheck PageSwapCache after page is locked (above) */
+ if (PageSwapCache(page) && !PageWriteback(page) &&
+ (one_user || vm_swap_full())) {
delete_from_swap_cache(page);
SetPageDirty(page);
}