From d345734267dbec642f4e34a9d392d2fd85b5fa9b Mon Sep 17 00:00:00 2001 From: Jeff Moyer Date: Sat, 16 Apr 2005 15:24:05 -0700 Subject: [PATCH] [PATCH] filemap_getpage can block when MAP_NONBLOCK specified We will return NULL from filemap_getpage when a page does not exist in the page cache and MAP_NONBLOCK is specified, here: page = find_get_page(mapping, pgoff); if (!page) { if (nonblock) return NULL; goto no_cached_page; } But we forget to do so when the page in the cache is not uptodate. The following could result in a blocking call: /* * Ok, found a page in the page cache, now we need to check * that it's up-to-date. */ if (!PageUptodate(page)) goto page_not_uptodate; Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/filemap.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/mm/filemap.c b/mm/filemap.c index 439b2bea8e34..93595c327bbd 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1379,8 +1379,13 @@ retry_find: * Ok, found a page in the page cache, now we need to check * that it's up-to-date. */ - if (!PageUptodate(page)) + if (!PageUptodate(page)) { + if (nonblock) { + page_cache_release(page); + return NULL; + } goto page_not_uptodate; + } success: /* -- 2.20.1