From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alex Elder Subject: [PATCH] libceph: don't clear bio_iter in prepare_write_message() Date: Sat, 09 Mar 2013 10:36:48 -0600 Message-ID: <513B6520.8050303@inktank.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from mail-ia0-f182.google.com ([209.85.210.182]:41114 "EHLO mail-ia0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758510Ab3CIQgv (ORCPT ); Sat, 9 Mar 2013 11:36:51 -0500 Received: by mail-ia0-f182.google.com with SMTP id b35so647060iac.27 for ; Sat, 09 Mar 2013 08:36:51 -0800 (PST) Sender: ceph-devel-owner@vger.kernel.org List-ID: To: ceph-devel@vger.kernel.org This patch is available in the branch "review/wip-msgr-refactor" (prior to 6 other patches) in the ceph-client git repository. That branch is based on branch "review/wip-abstract-2". -Alex At one time it was necessary to clear a message's bio_iter field to avoid a bad pointer dereference in write_partial_msg_pages(). That no longer seems to be the case. Here's why. The message's bio fields represent (in this case) outgoing data. Between where the bio_iter is made NULL in prepare_write_message() and the call in that function to prepare_message_data(), the bio fields are never used. In prepare_message_data(), init-bio_iter() is called, and the result of that overwrites the value in the message's bio_iter field. Because it gets overwritten anyway, there is no need to set it to NULL. So don't do it. This resolves: http://tracker.ceph.com/issues/4402 Signed-off-by: Alex Elder --- net/ceph/messenger.c | 4 ---- 1 file changed, 4 deletions(-) diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c index e75a03d..17d9321 100644 --- a/net/ceph/messenger.c +++ b/net/ceph/messenger.c @@ -804,10 +804,6 @@ static void prepare_write_message(struct ceph_connection *con) m->hdr.seq = cpu_to_le64(++con->out_seq); m->needs_out_seq = false; } -#ifdef CONFIG_BLOCK - else - m->bio_iter = NULL; -#endif dout("prepare_write_message %p seq %lld type %d len %d+%d+%d (%zd)\n", m, con->out_seq, le16_to_cpu(m->hdr.type), -- 1.7.9.5