Messages in this thread Patch in this message | | | From | Jeff Moyer <> | Date | Wed, 30 Mar 2005 15:15:46 -0500 | Subject | [patch] filemap_getpage can block when MAP_NONBLOCK specified |
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Hello,
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;
Patch attached.
Thanks,
Jeff
--- linux-2.6.11/mm/filemap.c.orig 2005-03-30 14:57:02.252975936 -0500 +++ linux-2.6.11/mm/filemap.c 2005-03-30 15:02:51.808835368 -0500 @@ -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: /* - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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