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Commit f000944d authored by Hugh Dickins's avatar Hugh Dickins Committed by Linus Torvalds
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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: default avatarHugh Dickins <hugh@veritas.com>
No-problems-with: Nick Piggin <npiggin@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent bb63be0a

mm/swap_state.c

+19 −34
Original line number Diff line number Diff line
@@ -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 */
@@ -334,17 +312,22 @@ struct page *read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask, 
				break;		/* Out of memory */

		}



		/*

		 * 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);