mm: abstract out wake_page_match() from wake_page_function() (c7510ab2) · Commits · 戴 / test

include/linux/pagemap.h

+37 −0

Original line number	Diff line number	Diff line
		@@ -496,6 +496,43 @@ static inline pgoff_t linear_page_index(struct vm_area_struct *vma,
		return pgoff;
		}

		/* This has the same layout as wait_bit_key - see fs/cachefiles/rdwr.c */
		struct wait_page_key {
		struct page *page;
		int bit_nr;
		int page_match;
		};

		struct wait_page_queue {
		struct page *page;
		int bit_nr;
		wait_queue_entry_t wait;
		};

		static inline int wake_page_match(struct wait_page_queue *wait_page,
		struct wait_page_key *key)
		{
		if (wait_page->page != key->page)
		return 0;
		key->page_match = 1;

		if (wait_page->bit_nr != key->bit_nr)
		return 0;

		/*
		* Stop walking if it's locked.
		* Is this safe if put_and_wait_on_page_locked() is in use?
		* Yes: the waker must hold a reference to this page, and if PG_locked
		* has now already been set by another task, that task must also hold
		* a reference to the same usage of this page; so there is no need
		* to walk on to wake even the put_and_wait_on_page_locked() callers.
		*/
		if (test_bit(key->bit_nr, &key->page->flags))
		return -1;

		return 1;
		}

		extern void __lock_page(struct page *page);
		extern int __lock_page_killable(struct page *page);
		extern int __lock_page_or_retry(struct page page, struct mm_struct mm,

+4 −31

Original line number	Diff line number	Diff line
		@@ -987,43 +987,16 @@ void __init pagecache_init(void)
		page_writeback_init();
		}

		/* This has the same layout as wait_bit_key - see fs/cachefiles/rdwr.c */
		struct wait_page_key {
		struct page *page;
		int bit_nr;
		int page_match;
		};

		struct wait_page_queue {
		struct page *page;
		int bit_nr;
		wait_queue_entry_t wait;
		};

		static int wake_page_function(wait_queue_entry_t wait, unsigned mode, int sync, void arg)
		{
		struct wait_page_key *key = arg;
		struct wait_page_queue *wait_page
		= container_of(wait, struct wait_page_queue, wait);
		int ret;

		if (wait_page->page != key->page)
		return 0;
		key->page_match = 1;

		if (wait_page->bit_nr != key->bit_nr)
		return 0;

		/*
		* Stop walking if it's locked.
		* Is this safe if put_and_wait_on_page_locked() is in use?
		* Yes: the waker must hold a reference to this page, and if PG_locked
		* has now already been set by another task, that task must also hold
		* a reference to the same usage of this page; so there is no need
		* to walk on to wake even the put_and_wait_on_page_locked() callers.
		*/
		if (test_bit(key->bit_nr, &key->page->flags))
		return -1;

		ret = wake_page_match(wait_page, key);
		if (ret != 1)
		return ret;
		return autoremove_wake_function(wait, mode, sync, key);
		}