From: "Toke Høiland-Jørgensen" <toke@redhat.com>
To: Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
bpf@vger.kernel.org, netdev@vger.kernel.org
Cc: "David S. Miller" <davem@davemloft.net>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>,
Jesper Dangaard Brouer <hawk@kernel.org>,
John Fastabend <john.fastabend@gmail.com>,
Thomas Gleixner <tglx@linutronix.de>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Subject: Re: [PATCH net-next 2/4] net: dev: Remove get_cpu() in netif_rx_internal().
Date: Thu, 03 Feb 2022 13:14:26 +0100 [thread overview]
Message-ID: <87sft0b10d.fsf@toke.dk> (raw)
In-Reply-To: <20220202122848.647635-3-bigeasy@linutronix.de>
Sebastian Andrzej Siewior <bigeasy@linutronix.de> writes:
> The get_cpu() usage was added in commit
> b0e28f1effd1d ("net: netif_rx() must disable preemption")
>
> because ip_dev_loopback_xmit() invoked netif_rx() with enabled preemtion
> causing a warning in smp_processor_id(). The function netif_rx() should
> only be invoked from an interrupt context which implies disabled
> preemption. The commit
> e30b38c298b55 ("ip: Fix ip_dev_loopback_xmit()")
>
> was addressing this and replaced netif_rx() with in netif_rx_ni() in
> ip_dev_loopback_xmit().
>
> Based on the discussion on the list, the former patch (b0e28f1effd1d)
> should not have been applied only the latter (e30b38c298b55).
>
> Remove get_cpu() since the function is supossed to be invoked from
> context with stable per-CPU pointers (either by disabling preemption or
> software interrupts).
>
> Link: https://lkml.kernel.org/r/20100415.013347.98375530.davem@davemloft.net
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
next prev parent reply other threads:[~2022-02-03 12:14 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-02 12:28 [PATCH net-next 0/4] net: dev: PREEMPT_RT fixups Sebastian Andrzej Siewior
2022-02-02 12:28 ` [PATCH net-next 1/4] net: dev: Remove the preempt_disable() in netif_rx_internal() Sebastian Andrzej Siewior
2022-02-02 17:10 ` Eric Dumazet
2022-02-03 12:00 ` Toke Høiland-Jørgensen
2022-02-03 12:17 ` Sebastian Andrzej Siewior
2022-02-03 12:41 ` Toke Høiland-Jørgensen
2022-02-03 15:50 ` Sebastian Andrzej Siewior
2022-02-04 15:20 ` [PATCH net-next v2 1/4] net: dev: Remove preempt_disable() and get_cpu() " Sebastian Andrzej Siewior
2022-02-04 16:31 ` Jakub Kicinski
2022-02-04 16:42 ` Sebastian Andrzej Siewior
2022-02-04 16:32 ` Eric Dumazet
2022-02-03 12:16 ` [PATCH net-next 1/4] net: dev: Remove the preempt_disable() " Sebastian Andrzej Siewior
2022-02-02 12:28 ` [PATCH net-next 2/4] net: dev: Remove get_cpu() " Sebastian Andrzej Siewior
2022-02-02 17:14 ` Eric Dumazet
2022-02-03 12:14 ` Toke Høiland-Jørgensen [this message]
2022-02-02 12:28 ` [PATCH net-next 3/4] net: dev: Makes sure netif_rx() can be invoked in any context Sebastian Andrzej Siewior
2022-02-02 16:50 ` Jakub Kicinski
2022-02-03 12:20 ` Sebastian Andrzej Siewior
2022-02-03 19:38 ` Jakub Kicinski
2022-02-02 17:43 ` Eric Dumazet
2022-02-03 12:19 ` Toke Høiland-Jørgensen
2022-02-03 15:10 ` Sebastian Andrzej Siewior
2022-02-03 15:25 ` Eric Dumazet
2022-02-03 15:40 ` Sebastian Andrzej Siewior
2022-02-03 16:18 ` Eric Dumazet
2022-02-03 16:44 ` Sebastian Andrzej Siewior
2022-02-03 17:45 ` Sebastian Andrzej Siewior
2022-02-04 13:00 ` [PATCH net-next v2 " Sebastian Andrzej Siewior
2022-02-04 18:46 ` Eric Dumazet
2022-02-02 12:28 ` [PATCH net-next 4/4] net: dev: Make rps_lock() disable interrupts Sebastian Andrzej Siewior
2022-02-02 16:47 ` Jakub Kicinski
2022-02-03 16:41 ` [PATCH net-next v2 " Sebastian Andrzej Siewior
2022-02-03 19:39 ` Jakub Kicinski
2022-02-02 16:14 ` [PATCH net-next 0/4] net: dev: PREEMPT_RT fixups Jakub Kicinski
2022-02-03 11:59 ` Toke Høiland-Jørgensen
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