tree df1aeae28ce51103a0c9eda8f7d40e463297b2ef
parent 41e5a6ac80c600e1f8bda0a4871f0b797e097d78
author Hua Zhong <hzhong@gmail.com> 1147711462 -0700
committer Linus Torvalds <torvalds@g5.osdl.org> 1147717256 -0700

[PATCH] fix can_share_swap_page() when !CONFIG_SWAP

can_share_swap_page() is used to check if the page has the last reference.
This avoids allocating a new page for COW if it's the last page.

However, if CONFIG_SWAP is not set, can_share_swap_page() is defined as 0,
thus always causes a copy for the last COW page.  The below simple patch
fixes it.

Signed-off-by: Hua Zhong <hzhong@gmail.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>