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uml: network driver MTU cleanups

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A bunch of MTU-related cleanups in the network code.

First, there is the addition of the notion of a maximally-sized packet, which
is the MTU plus headers.  This is used to size the skb that will receive a
packet.  This allows ether_adjust_skb to go away, as it was used to resize the
skb after it was allocated.

Since the skb passed into the low-level read routine is no longer resized, and
possibly reallocated, there, they (and the write routines) don't need to get
an sk_buff **.  They just need the sk_buff * now.  The callers of
ether_adjust_skb still need to do the skb_put, so that's now inlined.

The MAX_PACKET definitions in most of the drivers are gone.

The set_mtu methods were all the same and did nothing, so they can be
removed.

The ethertap driver had a typo which doubled the size of the packet rather
than adding two bytes to it.  It also wasn't defining its setup_size, causing
a zero-byte kmalloc and crash when the invalid pointer returned from kmalloc
was dereferenced.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Jeff Dike
2007-10-16 01:27:31 -07:00
committed by Linus Torvalds
parent cd1ae0e49b
commit b53f35a809
19 changed files with 80 additions and 188 deletions
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30
arch/um/os-Linux/drivers/ethertap_kern.c
View File

@@ -36,35 +36,24 @@ static void etap_init(struct net_device *dev, void *data)
printk("\n");
}
static int etap_read(int fd, struct sk_buff **skb, struct uml_net_private *lp)
static int etap_read(int fd, struct sk_buff *skb, struct uml_net_private *lp)
{
int len;
*skb = ether_adjust_skb(*skb, ETH_HEADER_ETHERTAP);
if (*skb == NULL)
return -ENOMEM;
len = net_recvfrom(fd, skb_mac_header(*skb),
(*skb)->dev->mtu + 2 * ETH_HEADER_ETHERTAP);
len = net_recvfrom(fd, skb_mac_header(skb),
skb->dev->mtu + 2 + ETH_HEADER_ETHERTAP);
if (len <= 0)
return len;
skb_pull(*skb, 2);
return(len);
skb_pull(skb, 2);
len -= 2;
return len;
}
static int etap_write(int fd, struct sk_buff **skb, struct uml_net_private *lp)
static int etap_write(int fd, struct sk_buff *skb, struct uml_net_private *lp)
{
if (skb_headroom(*skb) < 2) {
struct sk_buff *skb2;
skb2 = skb_realloc_headroom(*skb, 2);
dev_kfree_skb(*skb);
if (skb2 == NULL)
return -ENOMEM;
*skb = skb2;
}
skb_push(*skb, 2);
return net_send(fd, (*skb)->data, (*skb)->len);
skb_push(skb, 2);
return net_send(fd, skb->data, skb->len);
}
const struct net_kern_info ethertap_kern_info = {
@@ -99,6 +88,7 @@ static struct transport ethertap_transport = {
.user = &ethertap_user_info,
.kern = &ethertap_kern_info,
.private_size = sizeof(struct ethertap_data),
.setup_size = sizeof(struct ethertap_init),
};
static int register_ethertap(void)