IB/ipoib: Ensure that MTU isn't less than minimum permitted
[ Upstream commit
142a9c287613560edf5a03c8d142c8b6ebc1995b ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>