Commit 142a9c28 authored Aug 28, 2018 by Muhammad Sammar Committed by Jason Gunthorpe Sep 06, 2018

IB/ipoib: Ensure that MTU isn't less than minimum permitted



It is illegal to change MTU to a value lower than the minimum MTU
stated in ethernet spec. In addition to that we need to add 4 bytes
for encapsulation header (IPOIB_ENCAP_LEN).

Before "ifconfig ib0 mtu 0" command, succeeds while it obviously shouldn't.

Signed-off-by: Muhammad Sammar <muhammads@mellanox.com>
Reviewed-by: Feras Daoud <ferasda@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

parent 6c75520f

drivers/infiniband/ulp/ipoib/ipoib_main.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -243,7 +243,8 @@ static int ipoib_change_mtu(struct net_device *dev, int new_mtu)
		return 0;
		}

		if (new_mtu > IPOIB_UD_MTU(priv->max_ib_mtu))
		if (new_mtu < (ETH_MIN_MTU + IPOIB_ENCAP_LEN) \|\|
		new_mtu > IPOIB_UD_MTU(priv->max_ib_mtu))
		return -EINVAL;

		priv->admin_mtu = new_mtu;

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