Commit cc3327e7 authored Nov 23, 2005 by Hugh Dickins Committed by Linus Torvalds Nov 23, 2005

[PATCH] mm: unbloat get_futex_key

The follow_page changes in get_futex_key have left it with two almost
identical blocks, when handling the rare case of a futex in a nonlinear vma.
get_user_pages will itself do that follow_page, and its additional
find_extend_vma is hardly any overhead since the vma is already cached. Let's
just delete the follow_page block and let get_user_pages do it.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

parent 7b6ac9df

kernel/futex.c

+0 −15

Original line number	Diff line number	Diff line
		@@ -201,21 +201,6 @@ static int get_futex_key(unsigned long uaddr, union futex_key *key)
		* from swap. But that's a lot of code to duplicate here
		* for a rare case, so we simply fetch the page.
		*/

		/*
		* Do a quick atomic lookup first - this is the fastpath.
		*/
		page = follow_page(mm, uaddr, FOLL_TOUCH\|FOLL_GET);
		if (likely(page != NULL)) {
		key->shared.pgoff =
		page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
		put_page(page);
		return 0;
		}

		/*
		* Do it the general way.
		*/
		err = get_user_pages(current, mm, uaddr, 1, 0, 0, &page, NULL);
		if (err >= 0) {
		key->shared.pgoff =

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