From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hangbin Liu Subject: [PATCHv2 iproute2 0/2] libnetlink: malloc correct buff at run time Date: Wed, 13 Sep 2017 17:59:38 +0800 Message-ID: <1505296780-8444-1-git-send-email-liuhangbin@gmail.com> Cc: Stephen Hemminger , Michal Kubecek , Phil Sutter , Hangbin Liu To: netdev@vger.kernel.org Return-path: Received: from mail-pf0-f194.google.com ([209.85.192.194]:33265 "EHLO mail-pf0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751054AbdIMKAQ (ORCPT ); Wed, 13 Sep 2017 06:00:16 -0400 Received: by mail-pf0-f194.google.com with SMTP id h4so7334319pfk.0 for ; Wed, 13 Sep 2017 03:00:16 -0700 (PDT) Sender: netdev-owner@vger.kernel.org List-ID: With commit 72b365e8e0fd ("libnetlink: Double the dump buffer size") and 460c03f3f3cc ("iplink: double the buffer size also in iplink_get()"), we extend the buffer size to avoid truncated message with large numbers of VFs. But just as Michal said, this is not future-proof since the NIC number is increasing. We have customer even has 220+ VFs now. This is not make sense to hard code the buffer and increase it all the time. So let's just malloc the correct buff size at run time. Tested with most ip cmds and all look good. --- Changes since v1 by Phil: * rtnl_recvmsg(): * Rename output buffer pointer arg to 'answer'. * Use realloc() and make sure old buffer is freed on error. * Always return a newly allocated buffer for caller to free. * Retry on EINTR or EAGAIN so caller doesn't have to. * Return well-known negative error codes instead of just -1 on error. * Simplify goto label names. * If no answer pointer was passed, just free the buffer. * rtnl_dump_filter_l(): * Don't retry if rtnl_recvmsg() returns 0 as this can't happen anymore. * Free buffer returned by rtnl_recvmsg(). * __rtnl_talk(): * Don't retry if rtnl_recvmsg() returns 0 as this can't happen anymore. * Free buffer returned by rtnl_recvmsg(). * Return a newly allocated buffer for callers to free. * genl_ctrl_resolve_family() * Replace 'ghdr + GENL_HDRLEN' to 'answer + NLMSG_LENGTH(GENL_HDRLEN)' * tc_action_gd() * Call print_action() only if cmd == RTM_GETACTION * Change callers of rtnl_talk*() to always free the answer buffer if they passed one. * Drop extra request buffer space in callers if only used for holding output data. * Drop initialization of answer pointer if not necessary. * Change callers to pass NULL instead of answer pointer if they don't use it afterwards. Hangbin Liu (2): lib/libnetlink: re malloc buff if size is not enough lib/libnetlink: update rtnl_talk to support malloc buff at run time bridge/fdb.c | 2 +- bridge/link.c | 2 +- bridge/mdb.c | 2 +- bridge/vlan.c | 2 +- genl/ctrl.c | 19 +++++--- include/libnetlink.h | 6 +-- ip/ipaddress.c | 4 +- ip/ipaddrlabel.c | 4 +- ip/ipfou.c | 4 +- ip/ipila.c | 4 +- ip/ipl2tp.c | 8 ++-- ip/iplink.c | 38 +++++++-------- ip/iplink_vrf.c | 44 ++++++++--------- ip/ipmacsec.c | 2 +- ip/ipneigh.c | 2 +- ip/ipnetns.c | 23 +++++---- ip/ipntable.c | 2 +- ip/iproute.c | 26 ++++++---- ip/iprule.c | 6 +-- ip/ipseg6.c | 8 ++-- ip/iptoken.c | 2 +- ip/link_gre.c | 11 +++-- ip/link_gre6.c | 11 +++-- ip/link_ip6tnl.c | 11 +++-- ip/link_iptnl.c | 10 ++-- ip/link_vti.c | 11 +++-- ip/link_vti6.c | 11 +++-- ip/tcp_metrics.c | 8 ++-- ip/xfrm_policy.c | 25 +++++----- ip/xfrm_state.c | 30 ++++++------ lib/libgenl.c | 9 +++- lib/libnetlink.c | 132 +++++++++++++++++++++++++++++++++------------------ misc/ss.c | 2 +- tc/m_action.c | 12 ++--- tc/tc_class.c | 2 +- tc/tc_filter.c | 8 ++-- tc/tc_qdisc.c | 2 +- 37 files changed, 296 insertions(+), 209 deletions(-) -- 2.5.5