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[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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@ -1379,8 +1379,13 @@ static struct page * filemap_getpage(struct file *file, unsigned long pgoff,
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* Ok, found a page in the page cache, now we need to check
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* Ok, found a page in the page cache, now we need to check
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* that it's up-to-date.
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* that it's up-to-date.
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*/
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*/
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if (!PageUptodate(page))
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if (!PageUptodate(page)) {
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if (nonblock) {
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page_cache_release(page);
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return NULL;
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}
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goto page_not_uptodate;
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goto page_not_uptodate;
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}
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success:
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success:
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/*
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/*
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