From: Minchan Kim Date: Tue, 22 Mar 2011 23:30:53 +0000 (-0700) Subject: mm: introduce delete_from_page_cache() X-Git-Tag: v2.6.39-rc1~344 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=97cecb5a254fec22d28ef32235d888bfbfd7c783;p=pandora-kernel.git mm: introduce delete_from_page_cache() Presently we increase the page refcount in add_to_page_cache() but don't decrease it in remove_from_page_cache(). Such asymmetry adds confusion, requiring that callers notice it and a comment explaining why they release a page reference. It's not a good API. A long time ago, Hugh tried it (http://lkml.org/lkml/2004/10/24/140) but gave up because reiser4's drop_page() had to unlock the page between removing it from page cache and doing the page_cache_release(). But now the situation is changed. I think at least things in current mainline don't have any obstacles. The problem is for out-of-mainline filesystems - if they have done such things as reiser4, this patch could be a problem but they will discover this at compile time since we remove remove_from_page_cache(). This patch: This function works as just wrapper remove_from_page_cache(). The difference is that it decreases page references in itself. So caller have to make sure it has a page reference before calling. This patch is ready for removing remove_from_page_cache(). Signed-off-by: Minchan Kim Cc: Christoph Hellwig Acked-by: Hugh Dickins Acked-by: Mel Gorman Reviewed-by: KAMEZAWA Hiroyuki Reviewed-by: Johannes Weiner Reviewed-by: KOSAKI Motohiro Cc: Edward Shishkin Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Reading git-diff-tree failed