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From: Ido Schimmel <idosch@idosch.org>
To: Jiri Pirko <jiri@resnulli.us>
Cc: netdev@vger.kernel.org, davem@davemloft.net, kuba@kernel.org,
	dsahern@gmail.com, roopa@nvidia.com, mlxsw@nvidia.com,
	Ido Schimmel <idosch@nvidia.com>
Subject: Re: [RFC PATCH net-next 03/22] nexthop: Only emit a notification when nexthop is actually deleted
Date: Fri, 11 Sep 2020 17:40:48 +0300	[thread overview]
Message-ID: <20200911144048.GA3160975@shredder> (raw)
In-Reply-To: <20200908143959.GP2997@nanopsycho.orion>

On Tue, Sep 08, 2020 at 04:39:59PM +0200, Jiri Pirko wrote:
> Tue, Sep 08, 2020 at 11:10:18AM CEST, idosch@idosch.org wrote:
> >From: Ido Schimmel <idosch@nvidia.com>
> >
> >Currently, the delete notification is emitted from the error path of
> >nexthop_add() and replace_nexthop(), which can be confusing to listeners
> >as they are not familiar with the nexthop.
> >
> >Instead, only emit the notification when the nexthop is actually
> >deleted. The following sub-cases are covered:
> 
> Well, in theory, this might break some very odd app that is adding a
> route and checking the errors using this notification. My opinion is to
> allow this breakage to happen, but I'm usually too benevolent :)

There is no uAPI breakage since the patch is only changing the in-kernel
notification. After this patch the in-kernel and RTM_DELNEXTHOP netlink
notifications are both emitted from the same function (i.e.,
remove_nexthop()).

I'll reword the commit message to make it clear.

> 
> 
> >
> >1. User space deletes the nexthop
> >2. The nexthop is deleted by the kernel due to a netdev event (e.g.,
> >   nexthop device going down)
> >3. A group is deleted because its last nexthop is being deleted
> >4. The network namespace of the nexthop device is deleted
> >
> >Signed-off-by: Ido Schimmel <idosch@nvidia.com>
> >---
> > net/ipv4/nexthop.c | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> >diff --git a/net/ipv4/nexthop.c b/net/ipv4/nexthop.c
> >index 13d9219a9aa1..8c0f17c6863c 100644
> >--- a/net/ipv4/nexthop.c
> >+++ b/net/ipv4/nexthop.c
> >@@ -870,8 +870,6 @@ static void __remove_nexthop_fib(struct net *net, struct nexthop *nh)
> > 	bool do_flush = false;
> > 	struct fib_info *fi;
> > 
> >-	call_nexthop_notifiers(net, NEXTHOP_EVENT_DEL, nh);
> >-
> > 	list_for_each_entry(fi, &nh->fi_list, nh_list) {
> > 		fi->fib_flags |= RTNH_F_DEAD;
> > 		do_flush = true;
> >@@ -909,6 +907,8 @@ static void __remove_nexthop(struct net *net, struct nexthop *nh,
> > static void remove_nexthop(struct net *net, struct nexthop *nh,
> > 			   struct nl_info *nlinfo)
> > {
> >+	call_nexthop_notifiers(net, NEXTHOP_EVENT_DEL, nh);
> >+
> > 	/* remove from the tree */
> > 	rb_erase(&nh->rb_node, &net->nexthop.rb_root);
> > 
> >-- 
> >2.26.2
> >

  parent reply	other threads:[~2020-09-11 16:54 UTC|newest]

Thread overview: 56+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-08  9:10 [RFC PATCH net-next 00/22] nexthop: Add support for nexthop objects offload Ido Schimmel
2020-09-08  9:10 ` [RFC PATCH net-next 01/22] nexthop: Remove unused function declaration from header file Ido Schimmel
2020-09-08 14:29   ` David Ahern
2020-09-08  9:10 ` [RFC PATCH net-next 02/22] nexthop: Convert to blocking notification chain Ido Schimmel
2020-09-08 14:34   ` David Ahern
2020-09-08  9:10 ` [RFC PATCH net-next 03/22] nexthop: Only emit a notification when nexthop is actually deleted Ido Schimmel
2020-09-08 14:34   ` David Ahern
2020-09-08 14:39   ` Jiri Pirko
2020-09-08 14:42     ` David Ahern
2020-09-11 14:40     ` Ido Schimmel [this message]
2020-09-08  9:10 ` [RFC PATCH net-next 04/22] selftests: fib_nexthops: Test cleanup of FDB entries following nexthop deletion Ido Schimmel
2020-09-08 14:35   ` David Ahern
2020-09-08  9:10 ` [RFC PATCH net-next 05/22] nexthop: Add nexthop notification data structures Ido Schimmel
2020-09-08 14:43   ` David Ahern
2020-09-11 14:50     ` Ido Schimmel
2020-09-08  9:10 ` [RFC PATCH net-next 06/22] nexthop: Pass extack to nexthop notifier Ido Schimmel
2020-09-08 14:44   ` David Ahern
2020-09-08  9:10 ` [RFC PATCH net-next 07/22] nexthop: Prepare new notification info Ido Schimmel
2020-09-08 14:55   ` David Ahern
2020-09-11 15:01     ` Ido Schimmel
2020-09-08  9:10 ` [RFC PATCH net-next 08/22] nexthop: vxlan: Convert to " Ido Schimmel
2020-09-08 14:58   ` David Ahern
2020-09-11 15:05     ` Ido Schimmel
2020-09-08  9:10 ` [RFC PATCH net-next 09/22] rtnetlink: Add RTNH_F_TRAP flag Ido Schimmel
2020-09-08 15:02   ` David Ahern
2020-09-11 15:26     ` Ido Schimmel
2020-09-11 15:54       ` David Ahern
2020-09-08  9:10 ` [RFC PATCH net-next 10/22] nexthop: Allow setting "offload" and "trap" indications on nexthops Ido Schimmel
2020-09-08 15:14   ` David Ahern
2020-09-11 15:29     ` Ido Schimmel
2020-09-08  9:10 ` [RFC PATCH net-next 11/22] nexthop: Emit a notification when a nexthop is added Ido Schimmel
2020-09-08 15:21   ` David Ahern
2020-09-11 16:20     ` Ido Schimmel
2020-09-08  9:10 ` [RFC PATCH net-next 12/22] nexthop: Emit a notification when a nexthop group is replaced Ido Schimmel
2020-09-08 15:22   ` David Ahern
2020-09-08  9:10 ` [RFC PATCH net-next 13/22] nexthop: Emit a notification when a single nexthop " Ido Schimmel
2020-09-08 15:25   ` David Ahern
2020-09-11 16:24     ` Ido Schimmel
2020-09-08  9:10 ` [RFC PATCH net-next 14/22] nexthop: Emit a notification when a nexthop group is modified Ido Schimmel
2020-09-08 15:29   ` David Ahern
2020-09-08  9:10 ` [RFC PATCH net-next 15/22] nexthop: Emit a notification when a nexthop group is reduced Ido Schimmel
2020-09-08 15:33   ` David Ahern
2020-09-11 16:29     ` Ido Schimmel
2020-09-08  9:10 ` [RFC PATCH net-next 16/22] nexthop: Pass extack to register_nexthop_notifier() Ido Schimmel
2020-09-08 15:34   ` David Ahern
2020-09-08  9:10 ` [RFC PATCH net-next 17/22] nexthop: Replay nexthops when registering a notifier Ido Schimmel
2020-09-08 15:37   ` David Ahern
2020-09-11 16:40     ` Ido Schimmel
2020-09-11 16:47       ` David Ahern
2020-09-08  9:10 ` [RFC PATCH net-next 18/22] nexthop: Remove in-kernel route notifications when nexthop changes Ido Schimmel
2020-09-08 15:38   ` David Ahern
2020-09-08  9:10 ` [RFC PATCH net-next 19/22] netdevsim: Add devlink resource for nexthops Ido Schimmel
2020-09-08  9:10 ` [RFC PATCH net-next 20/22] netdevsim: Add dummy implementation for nexthop offload Ido Schimmel
2020-09-08  9:10 ` [RFC PATCH net-next 21/22] netdevsim: Allow programming routes with nexthop objects Ido Schimmel
2020-09-08 15:40   ` David Ahern
2020-09-08  9:10 ` [RFC PATCH net-next 22/22] selftests: netdevsim: Add test for nexthop offload API Ido Schimmel

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