rndis_host: reduce MTU instead of refusing to talk to devices with low max packet...

This patch makes the host RNDIS driver talk to RNDIS devices with an MTU
less than 1.5k, instead of refusing to talk to such a device.

Signed-Off-by: Thomas Sailer <t.sailer@alumni.ethz.ch>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
--

Hi Jeff,
are you the right person to send this to?
Nobody else seems to be wanting to forward this to Linus...

Thanks,
Tom

Signed-off-by: Jeff Garzik <jeff@garzik.org>

diff --git a/drivers/net/usb/rndis_host.c b/drivers/net/usb/rndis_host.c
index cd991a0f75bb3ef919d8ba9f513b982eba884163..1ebe3259be0d1dd937c9807249b3d657e8ef15a6 100644 (file)
--- a/drivers/net/usb/rndis_host.c
+++ b/drivers/net/usb/rndis_host.c
@@ -512,11 +512,19 @@ static int rndis_bind(struct usbnet *dev, struct usb_interface *intf)
        }
        tmp = le32_to_cpu(u.init_c->max_transfer_size);
        if (tmp < dev->hard_mtu) {
-               dev_err(&intf->dev,
-                       "dev can't take %u byte packets (max %u)\n",
-                       dev->hard_mtu, tmp);
-               retval = -EINVAL;
-               goto fail_and_release;
+               if (tmp <= net->hard_header_len) {
+                       dev_err(&intf->dev,
+                               "dev can't take %u byte packets (max %u)\n",
+                               dev->hard_mtu, tmp);
+                       retval = -EINVAL;
+                       goto fail_and_release;
+               }
+               dev->hard_mtu = tmp;
+               net->mtu = dev->hard_mtu - net->hard_header_len;
+               dev_warn(&intf->dev,
+                        "dev can't take %u byte packets (max %u), "
+                        "adjusting MTU to %u\n",
+                        dev->hard_mtu, tmp, net->mtu);
        }
 
        /* REVISIT:  peripheral "alignment" request is ignored ... */