From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f70.google.com (mail-pa0-f70.google.com [209.85.220.70]) by kanga.kvack.org (Postfix) with ESMTP id 50E646B0038 for ; Wed, 24 Aug 2016 16:37:26 -0400 (EDT) Received: by mail-pa0-f70.google.com with SMTP id ag5so45723442pad.2 for ; Wed, 24 Aug 2016 13:37:26 -0700 (PDT) Received: from mga06.intel.com (mga06.intel.com. [134.134.136.31]) by mx.google.com with ESMTPS id ik5si11256961pac.111.2016.08.24.13.37.25 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 24 Aug 2016 13:37:25 -0700 (PDT) From: Ross Zwisler Subject: [PATCH] mm: silently skip readahead for DAX inodes Date: Wed, 24 Aug 2016 14:37:12 -0600 Message-Id: <20160824203712.4580-1-ross.zwisler@linux.intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: linux-kernel@vger.kernel.org Cc: Ross Zwisler , Andrew Morton , Dan Williams , Dave Chinner , Dave Hansen , Jan Kara , linux-mm@kvack.org, linux-nvdimm@lists.01.org, Jeff Moyer , stable@vger.kernel.org For DAX inodes we need to be careful to never have page cache pages in the mapping->page_tree. This radix tree should be composed only of DAX exceptional entries and zero pages. ltp's readahead02 test was triggering a warning because we were trying to insert a DAX exceptional entry but found that a page cache page had already been inserted into the tree. This page was being inserted into the radix tree in response to a readahead(2) call. Readahead doesn't make sense for DAX inodes, but we don't want it to report a failure either. Instead, we just return success and don't do any work. Signed-off-by: Ross Zwisler Reported-by: Jeff Moyer Cc: stable@vger.kernel.org --- mm/readahead.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/mm/readahead.c b/mm/readahead.c index 65ec288..a9ba1be 100644 --- a/mm/readahead.c +++ b/mm/readahead.c @@ -8,6 +8,7 @@ */ #include +#include #include #include #include @@ -544,6 +545,9 @@ do_readahead(struct address_space *mapping, struct file *filp, if (!mapping || !mapping->a_ops) return -EINVAL; + if (dax_mapping(mapping)) + return 0; + return force_page_cache_readahead(mapping, filp, index, nr); } -- 2.9.0 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org