From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christian Brauner Subject: Re: [PATCH RFC v2 net-next 01/25] net/netlink: Pass extack to dump callbacks Date: Tue, 2 Oct 2018 13:07:39 +0200 Message-ID: <20181002110738.3jxivgmv56cmgtvj@brauner.io> References: <20181002002851.5002-1-dsahern@kernel.org> <20181002002851.5002-2-dsahern@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Cc: netdev@vger.kernel.org, davem@davemloft.net, jbenc@redhat.com, stephen@networkplumber.org, David Ahern To: David Ahern Return-path: Received: from mail-wr1-f68.google.com ([209.85.221.68]:42368 "EHLO mail-wr1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727321AbeJBRuc (ORCPT ); Tue, 2 Oct 2018 13:50:32 -0400 Received: by mail-wr1-f68.google.com with SMTP id b11-v6so1695110wru.9 for ; Tue, 02 Oct 2018 04:07:46 -0700 (PDT) Content-Disposition: inline In-Reply-To: <20181002002851.5002-2-dsahern@kernel.org> Sender: netdev-owner@vger.kernel.org List-ID: On Mon, Oct 01, 2018 at 05:28:27PM -0700, David Ahern wrote: > From: David Ahern > > Pass extack to dump callbacks by adding extack to netlink_dump_control, > transferring to netlink_callback and adding to the netlink_dump. Update > rtnetlink as the first user. Update netlink_dump to add any message after > the dump_done_errno. > > Signed-off-by: David Ahern This makes sense to me as it would allow us to report back more meaningful errors to userspace. > --- > include/linux/netlink.h | 2 ++ > net/core/rtnetlink.c | 1 + > net/netlink/af_netlink.c | 20 +++++++++++++++----- > 3 files changed, 18 insertions(+), 5 deletions(-) > > diff --git a/include/linux/netlink.h b/include/linux/netlink.h > index 71f121b66ca8..8fc90308a653 100644 > --- a/include/linux/netlink.h > +++ b/include/linux/netlink.h > @@ -176,6 +176,7 @@ struct netlink_callback { > void *data; > /* the module that dump function belong to */ > struct module *module; > + struct netlink_ext_ack *extack; > u16 family; > u16 min_dump_alloc; > unsigned int prev_seq, seq; > @@ -197,6 +198,7 @@ struct netlink_dump_control { > int (*done)(struct netlink_callback *); > void *data; > struct module *module; > + struct netlink_ext_ack *extack; > u16 min_dump_alloc; > }; > > diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c > index 35162e1b06ad..da91b38297d3 100644 > --- a/net/core/rtnetlink.c > +++ b/net/core/rtnetlink.c > @@ -4689,6 +4689,7 @@ static int rtnetlink_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh, > .dump = dumpit, > .min_dump_alloc = min_dump_alloc, > .module = owner, > + .extack = extack > }; > err = netlink_dump_start(rtnl, skb, nlh, &c); > /* netlink_dump_start() will keep a reference on > diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c > index e3a0538ec0be..7094156c94f0 100644 > --- a/net/netlink/af_netlink.c > +++ b/net/netlink/af_netlink.c > @@ -129,7 +129,7 @@ static const char *const nlk_cb_mutex_key_strings[MAX_LINKS + 1] = { > "nlk_cb_mutex-MAX_LINKS" > }; > > -static int netlink_dump(struct sock *sk); > +static int netlink_dump(struct sock *sk, struct netlink_ext_ack *extack); > > /* nl_table locking explained: > * Lookup and traversal are protected with an RCU read-side lock. Insertion > @@ -1981,7 +1981,7 @@ static int netlink_recvmsg(struct socket *sock, struct msghdr *msg, size_t len, > > if (nlk->cb_running && > atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2) { > - ret = netlink_dump(sk); > + ret = netlink_dump(sk, NULL); > if (ret) { > sk->sk_err = -ret; > sk->sk_error_report(sk); > @@ -2168,7 +2168,7 @@ EXPORT_SYMBOL(__nlmsg_put); > * It would be better to create kernel thread. > */ > > -static int netlink_dump(struct sock *sk) > +static int netlink_dump(struct sock *sk, struct netlink_ext_ack *extack) > { > struct netlink_sock *nlk = nlk_sk(sk); > struct netlink_callback *cb; > @@ -2222,8 +2222,11 @@ static int netlink_dump(struct sock *sk) > skb_reserve(skb, skb_tailroom(skb) - alloc_size); > netlink_skb_set_owner_r(skb, sk); > > - if (nlk->dump_done_errno > 0) > + if (nlk->dump_done_errno > 0) { > + cb->extack = extack; > nlk->dump_done_errno = cb->dump(skb, cb); > + cb->extack = NULL; > + } > > if (nlk->dump_done_errno > 0 || > skb_tailroom(skb) < nlmsg_total_size(sizeof(nlk->dump_done_errno))) { > @@ -2246,6 +2249,12 @@ static int netlink_dump(struct sock *sk) > memcpy(nlmsg_data(nlh), &nlk->dump_done_errno, > sizeof(nlk->dump_done_errno)); > > + if (extack && extack->_msg && nlk->flags & NETLINK_F_EXT_ACK) { > + nlh->nlmsg_flags |= NLM_F_ACK_TLVS; > + if (!nla_put_string(skb, NLMSGERR_ATTR_MSG, extack->_msg)) > + nlmsg_end(skb, nlh); > + } > + > if (sk_filter(sk, skb)) > kfree_skb(skb); > else > @@ -2307,6 +2316,7 @@ int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb, > cb->module = control->module; > cb->min_dump_alloc = control->min_dump_alloc; > cb->skb = skb; > + cb->extack = control->extack; > > if (control->start) { > ret = control->start(cb); > @@ -2319,7 +2329,7 @@ int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb, > > mutex_unlock(nlk->cb_mutex); > > - ret = netlink_dump(sk); > + ret = netlink_dump(sk, cb->extack); > > sock_put(sk); > > -- > 2.11.0 >