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Commit b522c94d authored by Michel Lespinasse's avatar Michel Lespinasse Committed by Linus Torvalds
Browse files

mm: filemap_fault: unique path for locking page 



Introduce a single location where filemap_fault() locks the desired page.
There used to be two such places, depending if the initial find_get_page()
was successful or not.

Signed-off-by: default avatarMichel Lespinasse <walken@google.com>
Acked-by: default avatarRik van Riel <riel@redhat.com>
Acked-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Reviewed-by: default avatarWu Fengguang <fengguang.wu@intel.com>
Cc: Ying Han <yinghan@google.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 182fea8f

mm/filemap.c

+11 −9
Original line number Diff line number Diff line
@@ -1539,25 +1539,27 @@ int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf) 
		 * waiting for the lock.

		 */

		do_async_mmap_readahead(vma, ra, file, page, offset);

		lock_page(page);



		/* Did it get truncated? */

		if (unlikely(page->mapping != mapping)) {

			unlock_page(page);

			put_page(page);

			goto no_cached_page;

		}

	} else {

		/* No page in the page cache at all */

		do_sync_mmap_readahead(vma, ra, file, offset);

		count_vm_event(PGMAJFAULT);

		ret = VM_FAULT_MAJOR;

retry_find:

		page = find_lock_page(mapping, offset);

		page = find_get_page(mapping, offset);

		if (!page)

			goto no_cached_page;

	}



	lock_page(page);



	/* Did it get truncated? */

	if (unlikely(page->mapping != mapping)) {

		unlock_page(page);

		put_page(page);

		goto retry_find;

	}

	VM_BUG_ON(page->index != offset);



	/*

	 * We have a locked page in the page cache, now we need to check

	 * that it's up-to-date. If not, it is going to be due to an error.