Subject: Re: [RFC PATCH v3 1/2] can: fix multiple delivery of a single CAN frame for overlapping CAN filters

From: Marc Kleine-Budde <[email-masked]>
Date: Wed, 01 Apr 2015 11:07:33 +0200

On 04/01/2015 07:50 AM, Oliver Hartkopp wrote:
> The CAN_RAW socket can set multiple CAN identifier specific filters that lead
> to multiple filters in the af_can.c filter processing. These filters are
> indenpendent from each other which leads to logical OR'ed filters when applied.
> 
> This patch makes sure that every CAN frame which is filtered for a specific
> socket is only delivered once to the user space. This is independent from the
> number of matching CAN filters of this socket.
> 
> As the raw_rcv() function is executed from NET_RX softirq the introduced
> variables are implemented as per-CPU variables to avoid extensive locking at
> CAN frame reception time.
> 
> Signed-off-by: Oliver Hartkopp <[email-masked]>
> ---
>  net/can/raw.c | 21 +++++++++++++++++++++
>  1 file changed, 21 insertions(+)
> 
> diff --git a/net/can/raw.c b/net/can/raw.c
> index 00c13ef..8c75446 100644
> --- a/net/can/raw.c
> +++ b/net/can/raw.c
> @@ -74,6 +74,11 @@ MODULE_ALIAS("can-proto-1");
>   * storing the single filter in dfilter, to avoid using dynamic memory.
>   */
>  
> +struct uniqframe {
> +	const struct sk_buff *skb;
> +	ktime_t tstamp;
> +};

Nitpick: as ktime_t is always a 64 bit value, I think putting it first
might provide better alignment.

No need to repost, I'll change this while applying, if you're okay with
this.

Marc
-- 
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