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Date: Mon, 27 Nov 2017 17:59:45 +0100
From: Jiri Pirko <jiri@resnulli.us>
To: Arnd Bergmann <arnd@arndb.de>
Cc: "David S. Miller" <davem@davemloft.net>, y2038@lists.linaro.org,
        Shuah Khan <shuah@kernel.org>, Willem de Bruijn <willemb@google.com>,
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        Andrey Konovalov <andreyknvl@google.com>,
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        Sowmini Varadhan <sowmini.varadhan@oracle.com>, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org
Subject: Re: [PATCH 2/2] [RFC] packet: experimental support for 64-bit
 timestamps
Message-ID: <20171127165945.GC1971@nanopsycho.orion>
References: <20171127162001.4055813-1-arnd@arndb.de>
 <20171127162001.4055813-2-arnd@arndb.de>
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Mon, Nov 27, 2017 at 05:19:25PM CET, arnd@arndb.de wrote:
>I tried to figure out what it would take to do a version 4 mmap packet
>socket interface to completely avoid the y2106 overflow problem. This is
>what I came up with, reusing most of the v3 code, except for the parts
>where we access the timestamps.
>
>For kselftest, I'm adding support for testing v4 in addition to v1-v3,
>but the test currently does not look at the timestamps, so it won't
>check that the timestamp format actually works as intended, only that
>I didn't break the parts that worked in the v3 selftest.
>
>Overall, this is more of a mess than I expected, so it's probably not
>worth doing a v4 format just for the timestamp, but the patch can serve
>as a reference for anyone that needs a new format for other reasons and
>fixes this along with the other changes.
>
>Signed-off-by: Arnd Bergmann <arnd@arndb.de>
>---

[...]


>@@ -250,7 +269,8 @@ struct tpacket_block_desc {
> enum tpacket_versions {
> 	TPACKET_V1,
> 	TPACKET_V2,
>-	TPACKET_V3
>+	TPACKET_V3,
>+	TPACKET_V4,

I wonder with how many versions are we going to eventually end up with :O