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| author | Jarod Wilson <jarod@redhat.com> | 2016-10-07 22:04:33 -0400 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2016-10-13 09:36:56 -0400 |
| commit | 61e84623ace35ce48975e8f90bbbac7557c43d61 (patch) | |
| tree | ee8fbe9b7ec279152c80f1ca48a8a53e3b4620e2 /net | |
| parent | 1b830996c1603225a96e233c3b09bf2b12607d78 (diff) | |
| download | linux-61e84623ace35ce48975e8f90bbbac7557c43d61.tar.gz linux-61e84623ace35ce48975e8f90bbbac7557c43d61.tar.bz2 linux-61e84623ace35ce48975e8f90bbbac7557c43d61.zip | |
net: centralize net_device min/max MTU checking
While looking into an MTU issue with sfc, I started noticing that almost
every NIC driver with an ndo_change_mtu function implemented almost
exactly the same range checks, and in many cases, that was the only
practical thing their ndo_change_mtu function was doing. Quite a few
drivers have either 68, 64, 60 or 46 as their minimum MTU value checked,
and then various sizes from 1500 to 65535 for their maximum MTU value. We
can remove a whole lot of redundant code here if we simple store min_mtu
and max_mtu in net_device, and check against those in net/core/dev.c's
dev_set_mtu().
In theory, there should be zero functional change with this patch, it just
puts the infrastructure in place. Subsequent patches will attempt to start
using said infrastructure, with theoretically zero change in
functionality.
CC: netdev@vger.kernel.org
Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/core/dev.c | 13 |
1 files changed, 11 insertions, 2 deletions
diff --git a/net/core/dev.c b/net/core/dev.c index f1fe26f66458..f376639e8774 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -6499,9 +6499,18 @@ int dev_set_mtu(struct net_device *dev, int new_mtu) if (new_mtu == dev->mtu) return 0; - /* MTU must be positive. */ - if (new_mtu < 0) + /* MTU must be positive, and in range */ + if (new_mtu < 0 || new_mtu < dev->min_mtu) { + net_err_ratelimited("%s: Invalid MTU %d requested, hw min %d\n", + dev->name, new_mtu, dev->min_mtu); return -EINVAL; + } + + if (dev->max_mtu > 0 && new_mtu > dev->max_mtu) { + net_err_ratelimited("%s: Invalid MTU %d requested, hw max %d\n", + dev->name, new_mtu, dev->min_mtu); + return -EINVAL; + } if (!netif_device_present(dev)) return -ENODEV; |