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Commit b53f35a8 authored by Jeff Dike's avatar Jeff Dike Committed by Linus Torvalds
Browse files

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: default avatarJeff Dike <jdike@linux.intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent cd1ae0e4

arch/um/drivers/daemon_kern.c

+5 −10
Original line number Diff line number Diff line
@@ -39,20 +39,15 @@ static void daemon_init(struct net_device *dev, void *data) 
	printk("\n");

}



static int daemon_read(int fd, struct sk_buff **skb,

		       struct uml_net_private *lp)

static int daemon_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_recvfrom(fd, skb_mac_header(*skb),

			    (*skb)->dev->mtu + ETH_HEADER_OTHER);

	return net_recvfrom(fd, skb_mac_header(skb),

			    skb->dev->mtu + ETH_HEADER_OTHER);

}



static int daemon_write(int fd, struct sk_buff **skb,

			struct uml_net_private *lp)

static int daemon_write(int fd, struct sk_buff *skb, struct uml_net_private *lp)

{

	return daemon_user_write(fd, (*skb)->data, (*skb)->len,

	return daemon_user_write(fd, skb->data, skb->len,

				 (struct daemon_data *) &lp->user);

}

arch/um/drivers/daemon_user.c

+2 −9
Original line number Diff line number Diff line
@@ -19,8 +19,6 @@ 
#include "um_malloc.h"

#include "user.h"



#define MAX_PACKET (ETH_MAX_PACKET + ETH_HEADER_OTHER)



enum request_type { REQ_NEW_CONTROL };



#define SWITCH_MAGIC 0xfeedface
@@ -184,18 +182,13 @@ int daemon_user_write(int fd, void *buf, int len, struct daemon_data *pri) 
	return net_sendto(fd, buf, len, data_addr, sizeof(*data_addr));

}



static int daemon_set_mtu(int mtu, void *data)

{

	return mtu;

}



const struct net_user_info daemon_user_info = {

	.init		= daemon_user_init,

	.open		= daemon_open,

	.close	 	= NULL,

	.remove	 	= daemon_remove,

	.set_mtu	= daemon_set_mtu,

	.add_address	= NULL,

	.delete_address = NULL,

	.max_packet	= MAX_PACKET - ETH_HEADER_OTHER

	.mtu		= ETH_MAX_PACKET,

	.max_packet	= ETH_MAX_PACKET + ETH_HEADER_OTHER,

};

arch/um/drivers/mcast_kern.c

+5 −8
Original line number Diff line number Diff line
@@ -39,18 +39,15 @@ static void mcast_init(struct net_device *dev, void *data) 
	       dpri->addr, dpri->port, dpri->ttl);

}



static int mcast_read(int fd, struct sk_buff **skb, struct uml_net_private *lp)

static int mcast_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_recvfrom(fd, skb_mac_header(*skb),

			    (*skb)->dev->mtu + ETH_HEADER_OTHER);

	return net_recvfrom(fd, skb_mac_header(skb),

			    skb->dev->mtu + ETH_HEADER_OTHER);

}



static int mcast_write(int fd, struct sk_buff **skb, struct uml_net_private *lp)

static int mcast_write(int fd, struct sk_buff *skb, struct uml_net_private *lp)

{

	return mcast_user_write(fd, (*skb)->data, (*skb)->len,

	return mcast_user_write(fd, skb->data, skb->len,

				(struct mcast_data *) &lp->user);

}

arch/um/drivers/mcast_user.c

+2 −9
Original line number Diff line number Diff line
@@ -20,8 +20,6 @@ 
#include "um_malloc.h"

#include "user.h"



#define MAX_PACKET (ETH_MAX_PACKET + ETH_HEADER_OTHER)



static struct sockaddr_in *new_addr(char *addr, unsigned short port)

{

	struct sockaddr_in *sin;
@@ -154,18 +152,13 @@ int mcast_user_write(int fd, void *buf, int len, struct mcast_data *pri) 
	return net_sendto(fd, buf, len, data_addr, sizeof(*data_addr));

}



static int mcast_set_mtu(int mtu, void *data)

{

	return mtu;

}



const struct net_user_info mcast_user_info = {

	.init		= mcast_user_init,

	.open		= mcast_open,

	.close	 	= mcast_close,

	.remove	 	= mcast_remove,

	.set_mtu	= mcast_set_mtu,

	.add_address	= NULL,

	.delete_address = NULL,

	.max_packet	= MAX_PACKET - ETH_HEADER_OTHER

	.mtu		= ETH_MAX_PACKET,

	.max_packet	= ETH_MAX_PACKET + ETH_HEADER_OTHER,

};

arch/um/drivers/net_kern.c

+8 −34
Original line number Diff line number Diff line
@@ -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)