From: Jakub Kicinski <kuba@kernel.org>
To: Eric Dumazet <edumazet@google.com>
Cc: "David S . Miller" <davem@davemloft.net>,
Paolo Abeni <pabeni@redhat.com>,
Ziwei Xiao <ziweixiao@google.com>,
Praveen Kaligineedi <pkaligineedi@google.com>,
Harshitha Ramamurthy <hramamurthy@google.com>,
Willem de Bruijn <willemb@google.com>,
Jeroen de Borst <jeroendb@google.com>,
Shailend Chand <shailend@google.com>,
netdev@vger.kernel.org, eric.dumazet@gmail.com
Subject: Re: [PATCH net-next 3/6] net: ethtool: perform pm duties outside of rtnl lock
Date: Thu, 20 Jun 2024 17:22:35 -0700 [thread overview]
Message-ID: <20240620172235.6e6fd7a5@kernel.org> (raw)
In-Reply-To: <20240620114711.777046-4-edumazet@google.com>
On Thu, 20 Jun 2024 11:47:08 +0000 Eric Dumazet wrote:
> Move pm_runtime_get_sync() and pm_runtime_put() out of __dev_ethtool
> to dev_ethtool() while RTNL is not yet held.
>
> These helpers do not depend on RTNL.
The helpers themselves don't, but can we assume no drivers have
implicit dependencies on calling netif_device_detach() under rtnl_lock,
and since the presence checks are under rtnl_lock they are currently
guaranteed not to get any callbacks past detach() + rtnl_unlock()?
I think its better to completely skip PM + presence + ->begin if driver
wants the op to be unlocked, but otherwise keep the locking as is
I also keep wondering whether we shouldn't use this as an opportunity
to introduce a "netdev instance lock". I think you mentioned we should
move away from rtnl for locking ethtool and ndos since most drivers
don't care at all about global state. Doing that is a huge project,
but maybe this is where we start?
next prev parent reply other threads:[~2024-06-21 0:22 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-06-20 11:47 [PATCH net-next 0/6] net: ethtool: reduce RTNL pressure in dev_ethtool() Eric Dumazet
2024-06-20 11:47 ` [PATCH net-next 1/6] net: ethtool: grab a netdev reference " Eric Dumazet
2024-06-20 11:47 ` [PATCH net-next 2/6] net: ethtool: add dev_ethtool_cap_check() Eric Dumazet
2024-06-20 11:47 ` [PATCH net-next 3/6] net: ethtool: perform pm duties outside of rtnl lock Eric Dumazet
2024-06-21 0:22 ` Jakub Kicinski [this message]
2024-06-21 0:59 ` Andrew Lunn
2024-06-21 2:11 ` Jakub Kicinski
2024-06-21 4:16 ` Eric Dumazet
2024-06-20 11:47 ` [PATCH net-next 4/6] net: ethtool: call ethtool_get_one_feature() without RTNL Eric Dumazet
2024-06-20 11:47 ` [PATCH net-next 5/6] net: ethtool: implement lockless ETHTOOL_GFLAGS Eric Dumazet
2024-06-20 11:47 ` [PATCH net-next 6/6] net: ethtool: add the ability to run ethtool_[gs]et_rxnfc() without RTNL Eric Dumazet
2024-06-20 17:45 ` Willem de Bruijn
2024-06-20 18:29 ` Eric Dumazet
2024-06-20 17:58 ` [PATCH net-next 0/6] net: ethtool: reduce RTNL pressure in dev_ethtool() Willem de Bruijn
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