From 93fac7041f082297b93655a0e49f659cd7520e40 Mon Sep 17 00:00:00 2001 From: Nick Piggin Date: Fri, 31 Mar 2006 02:29:56 -0800 Subject: [PATCH] [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 Acked-by: Hugh Dickins Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/feature-removal-schedule.txt | 12 ++++++++++++ include/linux/pagemap.h | 4 ++-- mm/swapfile.c | 14 ++++++++++---- 3 files changed, 24 insertions(+), 6 deletions(-) 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 @@ Why: The USB subsystem has changed a lot over time, and it has been Who: Greg Kroah-Hartman --------------------------- + +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 + +--------------------------- 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 @@ extern struct page * find_get_page(struct address_space *mapping, 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 @@ void free_swap_and_cache(swp_entry_t entry) 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); } -- 2.7.4