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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
Download Patch File Download Diff File Expand all files Collapse all files

42
arch/um/drivers/net_kern.c
View File

@@ -41,16 +41,16 @@ static int uml_net_rx(struct net_device *dev)
struct sk_buff *skb;
/* If we can't allocate memory, try again next round. */
skb = dev_alloc_skb(dev->mtu);
skb = dev_alloc_skb(lp->max_packet);
if (skb == NULL) {
lp->stats.rx_dropped++;
return 0;
}
skb->dev = dev;
skb_put(skb, dev->mtu);
skb_put(skb, lp->max_packet);
skb_reset_mac_header(skb);
pkt_len = (*lp->read)(lp->fd, &skb, lp);
pkt_len = (*lp->read)(lp->fd, skb, lp);
if (pkt_len > 0) {
skb_trim(skb, pkt_len);
@@ -178,7 +178,7 @@ static int uml_net_start_xmit(struct sk_buff *skb, struct net_device *dev)
spin_lock_irqsave(&lp->lock, flags);
len = (*lp->write)(lp->fd, &skb, lp);
len = (*lp->write)(lp->fd, skb, lp);
if (len == skb->len) {
lp->stats.tx_packets++;
@@ -240,22 +240,9 @@ static int uml_net_set_mac(struct net_device *dev, void *addr)
static int uml_net_change_mtu(struct net_device *dev, int new_mtu)
{
struct uml_net_private *lp = dev->priv;
int err = 0;
spin_lock_irq(&lp->lock);
new_mtu = (*lp->set_mtu)(new_mtu, &lp->user);
if (new_mtu < 0) {
err = new_mtu;
goto out;
}
dev->mtu = new_mtu;
out:
spin_unlock_irq(&lp->lock);
return err;
return 0;
}
static void uml_net_get_drvinfo(struct net_device *dev,
@@ -427,6 +414,7 @@ static void eth_configure(int n, void *init, char *mac,
.dev = dev,
.fd = -1,
.mac = { 0xfe, 0xfd, 0x0, 0x0, 0x0, 0x0},
.max_packet = transport->user->max_packet,
.protocol = transport->kern->protocol,
.open = transport->user->open,
.close = transport->user->close,
@@ -434,8 +422,7 @@ static void eth_configure(int n, void *init, char *mac,
.read = transport->kern->read,
.write = transport->kern->write,
.add_address = transport->user->add_address,
.delete_address = transport->user->delete_address,
.set_mtu = transport->user->set_mtu });
.delete_address = transport->user->delete_address });
init_timer(&lp->tl);
spin_lock_init(&lp->lock);
@@ -447,7 +434,7 @@ static void eth_configure(int n, void *init, char *mac,
goto out_unregister;
set_ether_mac(dev, device->mac);
dev->mtu = transport->user->max_packet;
dev->mtu = transport->user->mtu;
dev->open = uml_net_open;
dev->hard_start_xmit = uml_net_start_xmit;
dev->stop = uml_net_close;
@@ -807,19 +794,6 @@ static void close_devices(void)
__uml_exitcall(close_devices);
struct sk_buff *ether_adjust_skb(struct sk_buff *skb, int extra)
{
if ((skb != NULL) && (skb_tailroom(skb) < extra)) {
struct sk_buff *skb2;
skb2 = skb_copy_expand(skb, 0, extra, GFP_ATOMIC);
dev_kfree_skb(skb);
skb = skb2;
}
if (skb != NULL) skb_put(skb, extra);
return skb;
}
void iter_addresses(void *d, void (*cb)(unsigned char *, unsigned char *,
void *),
void *arg)