[patch 2/3] netpoll: Introduce a netpoll_info struct

From: Jeff Moyer
Date: Wed Jun 22 2005 - 20:37:12 EST

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Hi,

This patch introduces a netpoll_info structure, which the struct net_device
will now point to instead of pointing to a struct netpoll. The reason for
this is two-fold: 1) fields such as the rx_flags, poll_owner, and poll_lock
should be maintained per net_device, not per netpoll; and 2) this is a first
step in providing support for multiple netpoll clients to register against the
same net_device.

The struct netpoll is now pointed to by the netpoll_info structure. As
such, the previous behaviour of the code is preserved.

-Jeff

Signed-off-by: Jeff Moyer <jmoyer@xxxxxxxxxx>
---

--- linux-2.6.12/net/core/netpoll.c.orig 2005-06-22 20:11:06.673701253 -0400
+++ linux-2.6.12/net/core/netpoll.c 2005-06-22 20:11:45.323283581 -0400
@@ -130,19 +130,20 @@ static int checksum_udp(struct sk_buff *
*/
static void poll_napi(struct netpoll *np)
{
+ struct netpoll_info *npinfo = np->dev->npinfo;
int budget = 16;

if (test_bit(__LINK_STATE_RX_SCHED, &np->dev->state) &&
- np->poll_owner != smp_processor_id() &&
- spin_trylock(&np->poll_lock)) {
- np->rx_flags |= NETPOLL_RX_DROP;
+ npinfo->poll_owner != smp_processor_id() &&
+ spin_trylock(&npinfo->poll_lock)) {
+ npinfo->rx_flags |= NETPOLL_RX_DROP;
atomic_inc(&trapped);

np->dev->poll(np->dev, &budget);

atomic_dec(&trapped);
- np->rx_flags &= ~NETPOLL_RX_DROP;
- spin_unlock(&np->poll_lock);
+ npinfo->rx_flags &= ~NETPOLL_RX_DROP;
+ spin_unlock(&npinfo->poll_lock);
}
}

@@ -245,6 +246,7 @@ repeat:
static void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb)
{
int status;
+ struct netpoll_info *npinfo;

repeat:
if(!np || !np->dev || !netif_running(np->dev)) {
@@ -253,8 +255,9 @@ repeat:
}

/* avoid recursion */
- if(np->poll_owner == smp_processor_id() ||
- np->dev->xmit_lock_owner == smp_processor_id()) {
+ npinfo = np->dev->npinfo;
+ if (npinfo->poll_owner == smp_processor_id() ||
+ np->dev->xmit_lock_owner == smp_processor_id()) {
if (np->drop)
np->drop(skb);
else
@@ -341,14 +344,18 @@ void netpoll_send_udp(struct netpoll *np

static void arp_reply(struct sk_buff *skb)
{
+ struct netpoll_info *npinfo = skb->dev->npinfo;
struct arphdr *arp;
unsigned char *arp_ptr;
int size, type = ARPOP_REPLY, ptype = ETH_P_ARP;
u32 sip, tip;
struct sk_buff *send_skb;
- struct netpoll *np = skb->dev->np;
+ struct netpoll *np = NULL;

- if (!np) return;
+ if (npinfo)
+ np = npinfo->np;
+ if (!np)
+ return;

/* No arp on this interface */
if (skb->dev->flags & IFF_NOARP)
@@ -429,7 +436,7 @@ int __netpoll_rx(struct sk_buff *skb)
int proto, len, ulen;
struct iphdr *iph;
struct udphdr *uh;
- struct netpoll *np = skb->dev->np;
+ struct netpoll *np = skb->dev->npinfo->np;

if (!np->rx_hook)
goto out;
@@ -611,9 +618,7 @@ int netpoll_setup(struct netpoll *np)
{
struct net_device *ndev = NULL;
struct in_device *in_dev;
-
- np->poll_lock = SPIN_LOCK_UNLOCKED;
- np->poll_owner = -1;
+ struct netpoll_info *npinfo;

if (np->dev_name)
ndev = dev_get_by_name(np->dev_name);
@@ -624,7 +629,16 @@ int netpoll_setup(struct netpoll *np)
}

np->dev = ndev;
- ndev->np = np;
+ if (!ndev->npinfo) {
+ npinfo = kmalloc(sizeof(*npinfo), GFP_KERNEL);
+ if (!npinfo)
+ goto release;
+
+ npinfo->np = NULL;
+ npinfo->poll_lock = SPIN_LOCK_UNLOCKED;
+ npinfo->poll_owner = -1;
+ } else
+ npinfo = ndev->npinfo;

if (!ndev->poll_controller) {
printk(KERN_ERR "%s: %s doesn't support polling, aborting.\n",
@@ -693,12 +707,15 @@ int netpoll_setup(struct netpoll *np)
}

if(np->rx_hook)
- np->rx_flags = NETPOLL_RX_ENABLED;
+ npinfo->rx_flags = NETPOLL_RX_ENABLED;
+ npinfo->np = np;
+ ndev->npinfo = npinfo;

return 0;

release:
- ndev->np = NULL;
+ if (!ndev->npinfo)
+ kfree(npinfo);
np->dev = NULL;
dev_put(ndev);
return -1;
@@ -706,9 +723,11 @@ int netpoll_setup(struct netpoll *np)

void netpoll_cleanup(struct netpoll *np)
{
- if (np->dev)
- np->dev->np = NULL;
- dev_put(np->dev);
+ if (np->dev) {
+ if (np->dev->npinfo)
+ np->dev->npinfo->np = NULL;
+ dev_put(np->dev);
+ }
np->dev = NULL;
}

--- linux-2.6.12/include/linux/netpoll.h.orig 2005-06-22 20:11:15.326264524 -0400
+++ linux-2.6.12/include/linux/netpoll.h 2005-06-22 20:11:59.119992646 -0400
@@ -16,14 +16,18 @@ struct netpoll;
struct netpoll {
struct net_device *dev;
char dev_name[16], *name;
- int rx_flags;
void (*rx_hook)(struct netpoll *, int, char *, int);
void (*drop)(struct sk_buff *skb);
u32 local_ip, remote_ip;
u16 local_port, remote_port;
unsigned char local_mac[6], remote_mac[6];
+};
+
+struct netpoll_info {
spinlock_t poll_lock;
int poll_owner;
+ int rx_flags;
+ struct netpoll *np;
};

void netpoll_poll(struct netpoll *np);
@@ -39,22 +43,27 @@ void netpoll_queue(struct sk_buff *skb);
#ifdef CONFIG_NETPOLL
static inline int netpoll_rx(struct sk_buff *skb)
{
- return skb->dev->np && skb->dev->np->rx_flags && __netpoll_rx(skb);
+ struct netpoll_info *npinfo = skb->dev->npinfo;
+
+ if (!npinfo || !npinfo->rx_flags)
+ return 0;
+
+ return npinfo->np && __netpoll_rx(skb);
}

static inline void netpoll_poll_lock(struct net_device *dev)
{
- if (dev->np) {
- spin_lock(&dev->np->poll_lock);
- dev->np->poll_owner = smp_processor_id();
+ if (dev->npinfo) {
+ spin_lock(&dev->npinfo->poll_lock);
+ dev->npinfo->poll_owner = smp_processor_id();
}
}

static inline void netpoll_poll_unlock(struct net_device *dev)
{
- if (dev->np) {
- dev->np->poll_owner = -1;
- spin_unlock(&dev->np->poll_lock);
+ if (dev->npinfo) {
+ dev->npinfo->poll_owner = -1;
+ spin_unlock(&dev->npinfo->poll_lock);
}
}

--- linux-2.6.12/include/linux/netdevice.h.orig 2005-06-22 20:11:24.277778150 -0400
+++ linux-2.6.12/include/linux/netdevice.h 2005-06-22 20:11:45.325283249 -0400
@@ -41,7 +41,7 @@
struct divert_blk;
struct vlan_group;
struct ethtool_ops;
-struct netpoll;
+struct netpoll_info;
/* source back-compat hooks */
#define SET_ETHTOOL_OPS(netdev,ops) \
( (netdev)->ethtool_ops = (ops) )
@@ -468,7 +468,7 @@ struct net_device
unsigned char *haddr);
int (*neigh_setup)(struct net_device *dev, struct neigh_parms *);
#ifdef CONFIG_NETPOLL
- struct netpoll *np;
+ struct netpoll_info *npinfo;
#endif
#ifdef CONFIG_NET_POLL_CONTROLLER
void (*poll_controller)(struct net_device *dev);
-
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Next message: Jeff Moyer: "[patch 3/3] netpoll: allow multiple netpoll_clients to register against one interface"
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