uml: network driver MTU cleanups
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>
diff --git a/arch/um/os-Linux/drivers/ethertap_kern.c b/arch/um/os-Linux/drivers/ethertap_kern.c
index 542bcc58..04f11b9 100644
--- a/arch/um/os-Linux/drivers/ethertap_kern.c
+++ b/arch/um/os-Linux/drivers/ethertap_kern.c
@@ -36,35 +36,24 @@
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 @@
.user = ðertap_user_info,
.kern = ðertap_kern_info,
.private_size = sizeof(struct ethertap_data),
+ .setup_size = sizeof(struct ethertap_init),
};
static int register_ethertap(void)
diff --git a/arch/um/os-Linux/drivers/ethertap_user.c b/arch/um/os-Linux/drivers/ethertap_user.c
index 29404b9..4ff5536 100644
--- a/arch/um/os-Linux/drivers/ethertap_user.c
+++ b/arch/um/os-Linux/drivers/ethertap_user.c
@@ -222,11 +222,6 @@
pri->control_fd = -1;
}
-static int etap_set_mtu(int mtu, void *data)
-{
- return mtu;
-}
-
static void etap_add_addr(unsigned char *addr, unsigned char *netmask,
void *data)
{
@@ -254,8 +249,8 @@
.open = etap_open,
.close = etap_close,
.remove = NULL,
- .set_mtu = etap_set_mtu,
.add_address = etap_add_addr,
.delete_address = etap_del_addr,
- .max_packet = MAX_PACKET - ETH_HEADER_ETHERTAP
+ .mtu = ETH_MAX_PACKET,
+ .max_packet = ETH_MAX_PACKET + ETH_HEADER_ETHERTAP,
};
diff --git a/arch/um/os-Linux/drivers/tuntap_kern.c b/arch/um/os-Linux/drivers/tuntap_kern.c
index 9ade1f8..9d38480 100644
--- a/arch/um/os-Linux/drivers/tuntap_kern.c
+++ b/arch/um/os-Linux/drivers/tuntap_kern.c
@@ -35,20 +35,15 @@
printk("\n");
}
-static int tuntap_read(int fd, struct sk_buff **skb,
- struct uml_net_private *lp)
+static int tuntap_read(int fd, struct sk_buff *skb, struct uml_net_private *lp)
{
- *skb = ether_adjust_skb(*skb, ETH_HEADER_OTHER);
- if (*skb == NULL)
- return -ENOMEM;
- return net_read(fd, skb_mac_header(*skb),
- (*skb)->dev->mtu + ETH_HEADER_OTHER);
+ return net_read(fd, skb_mac_header(skb),
+ skb->dev->mtu + ETH_HEADER_OTHER);
}
-static int tuntap_write(int fd, struct sk_buff **skb,
- struct uml_net_private *lp)
+static int tuntap_write(int fd, struct sk_buff *skb, struct uml_net_private *lp)
{
- return net_write(fd, (*skb)->data, (*skb)->len);
+ return net_write(fd, skb->data, skb->len);
}
const struct net_kern_info tuntap_kern_info = {
diff --git a/arch/um/os-Linux/drivers/tuntap_user.c b/arch/um/os-Linux/drivers/tuntap_user.c
index 10714a4..6c55d3c 100644
--- a/arch/um/os-Linux/drivers/tuntap_user.c
+++ b/arch/um/os-Linux/drivers/tuntap_user.c
@@ -18,8 +18,6 @@
#include "tuntap.h"
#include "user.h"
-#define MAX_PACKET ETH_MAX_PACKET
-
static int tuntap_user_init(void *data, void *dev)
{
struct tuntap_data *pri = data;
@@ -206,18 +204,13 @@
pri->fd = -1;
}
-static int tuntap_set_mtu(int mtu, void *data)
-{
- return mtu;
-}
-
const struct net_user_info tuntap_user_info = {
.init = tuntap_user_init,
.open = tuntap_open,
.close = tuntap_close,
.remove = NULL,
- .set_mtu = tuntap_set_mtu,
.add_address = tuntap_add_addr,
.delete_address = tuntap_del_addr,
- .max_packet = MAX_PACKET
+ .mtu = ETH_MAX_PACKET,
+ .max_packet = ETH_MAX_PACKET + ETH_HEADER_OTHER,
};