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From: David Miller <davem@davemloft.net>
To: kubakici@wp.pl
Cc: jarod@redhat.com, linux-kernel@vger.kernel.org, netdev@vger.kernel.org
Subject: Re: [PATCH v3 net-next 2/2] net: deprecate eth_change_mtu, remove usage
Date: Mon, 17 Oct 2016 13:25:53 -0400 (EDT)	[thread overview]
Message-ID: <20161017.132553.1015830249902227215.davem@davemloft.net> (raw)
In-Reply-To: <20161017182049.4be802d1@jkicinski-Precision-T1700>

From: Jakub Kicinski <kubakici@wp.pl>
Date: Mon, 17 Oct 2016 18:20:49 +0100

> Hm.  I must be missing something really obvious.  I just booted
> net-next an hour ago and couldn't set MTU to anything larger than 1500
> on either nfp or igb.  As far as I can read the code it will set the
> max_mtu to 1500 in setup_ether() but none of the jumbo-capable drivers
> had been touched by Jarod so far...

Indeed.

Jarod, this doesn't work.

I guess the idea was that if the driver overrides ndo_change_mtu and
enforeced it's limits there, the driver would still work after your
changes.

But that isn't what is happening, look at the IGB example.

It uses ether_setup(), which sets those new defaults, but now when
the MTU is changed you enforce those default min/max before the
driver's ->ndo_change_mtu() has a change to step in front and make
the decision on it's own.

This means your changes pretty much did indeed break a lot of
drivers's ability to set larger than a 1500 byte MTU.

  reply	other threads:[~2016-10-17 17:26 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-09-12 20:11 [PATCH net-next 0/2] net: centralize net_device MTU bounds checking Jarod Wilson
2016-09-12 20:11 ` [PATCH net-next 1/2] net: centralize net_device min/max MTU checking Jarod Wilson
2016-09-12 20:11 ` [PATCH net-next 2/2] net: deprecate eth_change_mtu, remove usage Jarod Wilson
2016-09-13 21:59   ` kbuild test robot
2016-09-14 18:45     ` Jarod Wilson
2016-09-28 21:17 ` [PATCH v2 net-next 0/2] net: centralize net_device MTU bounds checking Jarod Wilson
2016-09-28 21:17   ` [PATCH v2 net-next 1/2] net: centralize net_device min/max MTU checking Jarod Wilson
2016-09-28 21:17   ` [PATCH v2 net-next 2/2] net: deprecate eth_change_mtu, remove usage Jarod Wilson
2016-09-28 22:20 ` [PATCH v2 net-next 0/2] net: centralize net_device MTU bounds checking Jarod Wilson
2016-09-28 22:20   ` [PATCH v2 net-next 1/2] net: centralize net_device min/max MTU checking Jarod Wilson
2016-09-30  9:37     ` Jakub Sitnicki
2016-10-03  2:43       ` David Miller
2016-10-03 17:46         ` Jarod Wilson
2016-10-08  2:04         ` [PATCH v3 net-next 0/2] net: centralize net_device MTU bounds checking Jarod Wilson
2016-10-08  2:04           ` [PATCH v3 net-next 1/2] net: centralize net_device min/max MTU checking Jarod Wilson
2016-10-08  2:04           ` [PATCH v3 net-next 2/2] net: deprecate eth_change_mtu, remove usage Jarod Wilson
2016-10-17 16:20             ` Jakub Kicinski
2016-10-17 16:49               ` David Miller
2016-10-17 17:00                 ` Jakub Kicinski
2016-10-17 17:04                   ` Jakub Kicinski
2016-10-17 17:15                   ` David Miller
2016-10-17 17:20                     ` Jakub Kicinski
2016-10-17 17:25                       ` David Miller [this message]
2016-10-17 20:07                         ` Jarod Wilson
2016-10-17 20:22                           ` Jarod Wilson
2016-10-13 13:37           ` [PATCH v3 net-next 0/2] net: centralize net_device MTU bounds checking David Miller
2016-09-28 22:20   ` [PATCH v2 net-next 2/2] net: deprecate eth_change_mtu, remove usage Jarod Wilson

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