From: Jakub Kicinski <kuba@kernel.org>
To: Petr Machata <petrm@nvidia.com>
Cc: "David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Paolo Abeni <pabeni@redhat.com>, Simon Horman <horms@kernel.org>,
<netdev@vger.kernel.org>, Ido Schimmel <idosch@nvidia.com>,
Kuniyuki Iwashima <kuniyu@google.com>,
Breno Leitao <leitao@debian.org>,
Andy Roulin <aroulin@nvidia.com>,
"Francesco Ruggeri" <fruggeri@arista.com>,
Stephen Hemminger <stephen@networkplumber.org>,
<mlxsw@nvidia.com>
Subject: Re: [PATCH net-next v2 6/8] net: core: neighbour: Reorder netlink & internal notification
Date: Sun, 25 Jan 2026 14:59:22 -0800 [thread overview]
Message-ID: <20260125145922.36ba88ad@kernel.org> (raw)
In-Reply-To: <f3ef74d5460f14c4d102b8a5857d4a6624da9a5a.1769012464.git.petrm@nvidia.com>
On Wed, 21 Jan 2026 17:43:40 +0100 Petr Machata wrote:
> The netlink message needs to be send inside the critical section where the
> neighbor is changed, so that it reflects the notified-upon neighbor state.
> On the other hand, there is no such need in case of notifier chain: the
> listeners do not assume lock, and often in fact just schedule a delayed
> work to act on the neighbor later. At least one in fact also takes the
> neighbor lock.
>
> This requires that the netlink notification be done before the internal
> notifier chain message is sent. That is safe to do, because the current
> listeners, as well as __neigh_notify(), only read the updated neighbor
> fields, and never modify them. (Apart from locking.)
Hopefully we're not setting a trap here that some driver will later
fall into.
next prev parent reply other threads:[~2026-01-25 22:59 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-21 16:43 [PATCH net-next v2 0/8] net: neighbour: Notify changes atomically Petr Machata
2026-01-21 16:43 ` [PATCH net-next v2 1/8] net: core: neighbour: Add a neigh_fill_info() helper for when lock not held Petr Machata
2026-01-21 16:43 ` [PATCH net-next v2 2/8] net: core: neighbour: Call __neigh_notify() under a lock Petr Machata
2026-01-21 16:43 ` [PATCH net-next v2 3/8] net: core: neighbour: Extract ARP queue processing to a helper function Petr Machata
2026-01-21 16:43 ` [PATCH net-next v2 4/8] net: core: neighbour: Process ARP queue later Petr Machata
2026-01-21 16:43 ` [PATCH net-next v2 5/8] net: core: neighbour: Inline neigh_update_notify() calls Petr Machata
2026-01-21 16:43 ` [PATCH net-next v2 6/8] net: core: neighbour: Reorder netlink & internal notification Petr Machata
2026-01-25 22:59 ` Jakub Kicinski [this message]
2026-01-21 16:43 ` [PATCH net-next v2 7/8] net: core: neighbour: Make one netlink notification atomically Petr Machata
2026-01-21 16:43 ` [PATCH net-next v2 8/8] net: core: neighbour: Make another " Petr Machata
2026-01-23 15:28 ` [PATCH net-next v2 0/8] net: neighbour: Notify changes atomically Simon Horman
2026-01-25 23:00 ` patchwork-bot+netdevbpf
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20260125145922.36ba88ad@kernel.org \
--to=kuba@kernel.org \
--cc=aroulin@nvidia.com \
--cc=davem@davemloft.net \
--cc=edumazet@google.com \
--cc=fruggeri@arista.com \
--cc=horms@kernel.org \
--cc=idosch@nvidia.com \
--cc=kuniyu@google.com \
--cc=leitao@debian.org \
--cc=mlxsw@nvidia.com \
--cc=netdev@vger.kernel.org \
--cc=pabeni@redhat.com \
--cc=petrm@nvidia.com \
--cc=stephen@networkplumber.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.