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[PATCH] filemap_getpage can block when MAP_NONBLOCK specified

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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>
This commit is contained in:
Jeff Moyer 2005-04-16 15:24:05 -07:00 committed by Linus Torvalds
parent 41aac24f8f
commit d345734267
1 changed files with 6 additions and 1 deletions
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7
mm/filemap.c
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@ -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
* 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:
/*