Commit d3457342 authored by Jeff Moyer's avatar Jeff Moyer Committed by Linus Torvalds

[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: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 41aac24f
...@@ -1379,8 +1379,13 @@ static struct page * filemap_getpage(struct file *file, unsigned long pgoff, ...@@ -1379,8 +1379,13 @@ static struct page * filemap_getpage(struct file *file, unsigned long pgoff,
* Ok, found a page in the page cache, now we need to check * Ok, found a page in the page cache, now we need to check
* that it's up-to-date. * that it's up-to-date.
*/ */
if (!PageUptodate(page)) if (!PageUptodate(page)) {
if (nonblock) {
page_cache_release(page);
return NULL;
}
goto page_not_uptodate; goto page_not_uptodate;
}
success: success:
/* /*
......
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