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authorHugh Dickins <hugh@veritas.com>2008-02-04 22:28:49 -0800
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2008-02-05 09:44:15 -0800
commitf000944d03a5b74ab3c92b2fcdf0e944cc898065 (patch)
tree07b64eeed416f3869a3fc4f06d00bd1fb1321f20 /mm/swap_state.c
parentbb63be0a091c512fb566ee235eb8320d5831b6e2 (diff)
downloadvexpress-lsk-f000944d03a5b74ab3c92b2fcdf0e944cc898065.tar.gz
tmpfs: shuffle add_to_swap_caches
add_to_swap_cache doesn't amount to much: merge it into its sole caller read_swap_cache_async. But we'll be needing to call __add_to_swap_cache from shmem.c, so promote it to the new add_to_swap_cache. Both were static, so there's no interface confusion to worry about. And lose that inappropriate "Anon pages are already on the LRU" comment in the merging: they're not already on the LRU, as Nick Piggin noticed. Signed-off-by: Hugh Dickins <hugh@veritas.com> No-problems-with: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/swap_state.c')
-rw-r--r--mm/swap_state.c53
1 files changed, 19 insertions, 34 deletions
diff --git a/mm/swap_state.c b/mm/swap_state.c
index 18fce3613e5..c75eda2c9cc 100644
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -64,10 +64,10 @@ void show_swap_cache_info(void)
}
/*
- * __add_to_swap_cache resembles add_to_page_cache on swapper_space,
+ * add_to_swap_cache resembles add_to_page_cache on swapper_space,
* but sets SwapCache flag and private instead of mapping and index.
*/
-static int __add_to_swap_cache(struct page *page, swp_entry_t entry,
+static int add_to_swap_cache(struct page *page, swp_entry_t entry,
gfp_t gfp_mask)
{
int error;
@@ -94,28 +94,6 @@ static int __add_to_swap_cache(struct page *page, swp_entry_t entry,
return error;
}
-static int add_to_swap_cache(struct page *page, swp_entry_t entry,
- gfp_t gfp_mask)
-{
- int error;
-
- BUG_ON(PageLocked(page));
- if (!swap_duplicate(entry))
- return -ENOENT;
-
- SetPageLocked(page);
- error = __add_to_swap_cache(page, entry, gfp_mask & GFP_KERNEL);
- /*
- * Anon pages are already on the LRU, we don't run lru_cache_add here.
- */
- if (error) {
- ClearPageLocked(page);
- swap_free(entry);
- return error;
- }
- return 0;
-}
-
/*
* This must be called only on pages that have
* been verified to be in the swap cache.
@@ -165,7 +143,7 @@ int add_to_swap(struct page * page, gfp_t gfp_mask)
/*
* Add it to the swap cache and mark it dirty
*/
- err = __add_to_swap_cache(page, entry,
+ err = add_to_swap_cache(page, entry,
gfp_mask|__GFP_NOMEMALLOC|__GFP_NOWARN);
switch (err) {
@@ -210,7 +188,7 @@ void delete_from_swap_cache(struct page *page)
*/
int move_to_swap_cache(struct page *page, swp_entry_t entry)
{
- int err = __add_to_swap_cache(page, entry, GFP_ATOMIC);
+ int err = add_to_swap_cache(page, entry, GFP_ATOMIC);
if (!err) {
remove_from_page_cache(page);
page_cache_release(page); /* pagecache ref */
@@ -335,16 +313,21 @@ struct page *read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
}
/*
+ * Swap entry may have been freed since our caller observed it.
+ */
+ if (!swap_duplicate(entry))
+ break;
+
+ /*
* Associate the page with swap entry in the swap cache.
- * May fail (-ENOENT) if swap entry has been freed since
- * our caller observed it. May fail (-EEXIST) if there
- * is already a page associated with this entry in the
- * swap cache: added by a racing read_swap_cache_async,
- * or by try_to_swap_out (or shmem_writepage) re-using
- * the just freed swap entry for an existing page.
+ * May fail (-EEXIST) if there is already a page associated
+ * with this entry in the swap cache: added by a racing
+ * read_swap_cache_async, or add_to_swap or shmem_writepage
+ * re-using the just freed swap entry for an existing page.
* May fail (-ENOMEM) if radix-tree node allocation failed.
*/
- err = add_to_swap_cache(new_page, entry, gfp_mask);
+ SetPageLocked(new_page);
+ err = add_to_swap_cache(new_page, entry, gfp_mask & GFP_KERNEL);
if (!err) {
/*
* Initiate read into locked page and return.
@@ -353,7 +336,9 @@ struct page *read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
swap_readpage(NULL, new_page);
return new_page;
}
- } while (err != -ENOENT && err != -ENOMEM);
+ ClearPageLocked(new_page);
+ swap_free(entry);
+ } while (err != -ENOMEM);
if (new_page)
page_cache_release(new_page);