From: Jeff Moyer <jmoyer@redhat.com>
Date: Sat, 16 Apr 2005 22:24:05 +0000 (-0700)
Subject: [PATCH] filemap_getpage can block when MAP_NONBLOCK specified
X-Git-Tag: v2.6.12-rc3~230
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d345734267dbec642f4e34a9d392d2fd85b5fa9b;p=pandora-kernel.git

[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 <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---

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