[NET]: Convert RTNL to mutex.

This patch turns the RTNL from a semaphore to a new 2.6.16 mutex and
gets rid of some of the leftover legacy.
Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/8139too.c

@@ -1605,7 +1605,7 @@ static void rtl8139_thread (void *_data)
 	if (tp->watchdog_fired) {
 		tp->watchdog_fired = 0;
 		rtl8139_tx_timeout_task(_data);
-	} else if (rtnl_shlock_nowait() == 0) {
+	} else if (rtnl_trylock()) {
 		rtl8139_thread_iter (dev, tp, tp->mmio_addr);
 		rtnl_unlock ();
 	} else {

include/linux/rtnetlink.h

@@ -907,6 +907,7 @@ struct tcamsg
 #ifdef __KERNEL__
 
 #include <linux/config.h>
+#include <linux/mutex.h>
 
 extern size_t rtattr_strlcpy(char *dest, const struct rtattr *rta, size_t size);
 static __inline__ int rtattr_strcmp(const struct rtattr *rta, const char *str)
@@ -1038,24 +1039,17 @@ __rta_reserve(struct sk_buff *skb, int attrtype, int attrlen)
 
 extern void rtmsg_ifinfo(int type, struct net_device *dev, unsigned change);
 
-extern struct semaphore rtnl_sem;
-
-#define rtnl_shlock()		down(&rtnl_sem)
-#define rtnl_shlock_nowait()	down_trylock(&rtnl_sem)
-
-#define rtnl_shunlock()	do { up(&rtnl_sem); \
-		             if (rtnl && rtnl->sk_receive_queue.qlen) \
-				     rtnl->sk_data_ready(rtnl, 0); \
-		        } while(0)
-
+/* RTNL is used as a global lock for all changes to network configuration  */
 extern void rtnl_lock(void);
-extern int rtnl_lock_interruptible(void);
 extern void rtnl_unlock(void);
+extern int rtnl_trylock(void);
+
 extern void rtnetlink_init(void);
+extern void __rtnl_unlock(void);
 
 #define ASSERT_RTNL() do { \
-	if (unlikely(down_trylock(&rtnl_sem) == 0)) { \
-		up(&rtnl_sem); \
+	if (unlikely(rtnl_trylock())) { \
+		rtnl_unlock(); \
 		printk(KERN_ERR "RTNL: assertion failed at %s (%d)\n", \
 		       __FILE__,  __LINE__); \
 		dump_stack(); \

net/core/dev.c

@@ -2466,9 +2466,9 @@ int dev_ioctl(unsigned int cmd, void __user *arg)
 	 */
 
 	if (cmd == SIOCGIFCONF) {
-		rtnl_shlock();
+		rtnl_lock();
 		ret = dev_ifconf((char __user *) arg);
-		rtnl_shunlock();
+		rtnl_unlock();
 		return ret;
 	}
 	if (cmd == SIOCGIFNAME)
@@ -2877,7 +2877,7 @@ static void netdev_wait_allrefs(struct net_device *dev)
 	rebroadcast_time = warning_time = jiffies;
 	while (atomic_read(&dev->refcnt) != 0) {
 		if (time_after(jiffies, rebroadcast_time + 1 * HZ)) {
-			rtnl_shlock();
+			rtnl_lock();
 
 			/* Rebroadcast unregister notification */
 			notifier_call_chain(&netdev_chain,
@@ -2894,7 +2894,7 @@ static void netdev_wait_allrefs(struct net_device *dev)
 				linkwatch_run_queue();
 			}
 
-			rtnl_shunlock();
+			__rtnl_unlock();
 
 			rebroadcast_time = jiffies;
 		}

net/core/link_watch.c

@@ -139,9 +139,9 @@ static void linkwatch_event(void *dummy)
 	linkwatch_nextevent = jiffies + HZ;
 	clear_bit(LW_RUNNING, &linkwatch_flags);
 
-	rtnl_shlock();
+	rtnl_lock();
 	linkwatch_run_queue();
-	rtnl_shunlock();
+	rtnl_unlock();
 }
 
 

net/core/netpoll.c

@@ -669,14 +669,14 @@ int netpoll_setup(struct netpoll *np)
 		printk(KERN_INFO "%s: device %s not up yet, forcing it\n",
 		       np->name, np->dev_name);
 
-		rtnl_shlock();
+		rtnl_lock();
 		if (dev_change_flags(ndev, ndev->flags | IFF_UP) < 0) {
 			printk(KERN_ERR "%s: failed to open %s\n",
 			       np->name, np->dev_name);
-			rtnl_shunlock();
+			rtnl_unlock();
 			goto release;
 		}
-		rtnl_shunlock();
+		rtnl_unlock();
 
 		atleast = jiffies + HZ/10;
  		atmost = jiffies + 4*HZ;

net/core/rtnetlink.c

@@ -35,6 +35,7 @@
 #include <linux/skbuff.h>
 #include <linux/init.h>
 #include <linux/security.h>
+#include <linux/mutex.h>
 
 #include <asm/uaccess.h>
 #include <asm/system.h>
@@ -51,25 +52,31 @@
 #include <net/pkt_sched.h>
 #include <net/netlink.h>
 
-DECLARE_MUTEX(rtnl_sem);
+static DEFINE_MUTEX(rtnl_mutex);
 
 void rtnl_lock(void)
 {
-	rtnl_shlock();
+	mutex_lock(&rtnl_mutex);
 }
 
-int rtnl_lock_interruptible(void)
+void __rtnl_unlock(void)
 {
-	return down_interruptible(&rtnl_sem);
+	mutex_unlock(&rtnl_mutex);
 }
 
 void rtnl_unlock(void)
 {
-	rtnl_shunlock();
-
+	mutex_unlock(&rtnl_mutex);
+	if (rtnl && rtnl->sk_receive_queue.qlen)
+		rtnl->sk_data_ready(rtnl, 0);
 	netdev_run_todo();
 }
 
+int rtnl_trylock(void)
+{
+	return mutex_trylock(&rtnl_mutex);
+}
+
 int rtattr_parse(struct rtattr *tb[], int maxattr, struct rtattr *rta, int len)
 {
 	memset(tb, 0, sizeof(struct rtattr*)*maxattr);
@@ -625,9 +632,9 @@ static void rtnetlink_rcv(struct sock *sk, int len)
 	unsigned int qlen = 0;
 
 	do {
-		rtnl_lock();
+		mutex_lock(&rtnl_mutex);
 		netlink_run_queue(sk, &qlen, &rtnetlink_rcv_msg);
-		up(&rtnl_sem);
+		mutex_unlock(&rtnl_mutex);
 
 		netdev_run_todo();
 	} while (qlen);
@@ -704,6 +711,5 @@ EXPORT_SYMBOL(rtnetlink_links);
 EXPORT_SYMBOL(rtnetlink_put_metrics);
 EXPORT_SYMBOL(rtnl);
 EXPORT_SYMBOL(rtnl_lock);
-EXPORT_SYMBOL(rtnl_lock_interruptible);
-EXPORT_SYMBOL(rtnl_sem);
+EXPORT_SYMBOL(rtnl_trylock);
 EXPORT_SYMBOL(rtnl_unlock);

net/ipv4/igmp.c

@@ -1730,7 +1730,7 @@ int ip_mc_join_group(struct sock *sk , struct ip_mreqn *imr)
 	if (!MULTICAST(addr))
 		return -EINVAL;
 
-	rtnl_shlock();
+	rtnl_lock();
 
 	in_dev = ip_mc_find_dev(imr);
 
@@ -1763,7 +1763,7 @@ int ip_mc_join_group(struct sock *sk , struct ip_mreqn *imr)
 	ip_mc_inc_group(in_dev, addr);
 	err = 0;
 done:
-	rtnl_shunlock();
+	rtnl_unlock();
 	return err;
 }
 
@@ -1837,7 +1837,7 @@ int ip_mc_source(int add, int omode, struct sock *sk, struct
 	if (!MULTICAST(addr))
 		return -EINVAL;
 
-	rtnl_shlock();
+	rtnl_lock();
 
 	imr.imr_multiaddr.s_addr = mreqs->imr_multiaddr;
 	imr.imr_address.s_addr = mreqs->imr_interface;
@@ -1947,7 +1947,7 @@ int ip_mc_source(int add, int omode, struct sock *sk, struct
 	ip_mc_add_src(in_dev, &mreqs->imr_multiaddr, omode, 1, 
 		&mreqs->imr_sourceaddr, 1);
 done:
-	rtnl_shunlock();
+	rtnl_unlock();
 	if (leavegroup)
 		return ip_mc_leave_group(sk, &imr);
 	return err;
@@ -1970,7 +1970,7 @@ int ip_mc_msfilter(struct sock *sk, struct ip_msfilter *msf, int ifindex)
 	    msf->imsf_fmode != MCAST_EXCLUDE)
 		return -EINVAL;
 
-	rtnl_shlock();
+	rtnl_lock();
 
 	imr.imr_multiaddr.s_addr = msf->imsf_multiaddr;
 	imr.imr_address.s_addr = msf->imsf_interface;
@@ -2030,7 +2030,7 @@ int ip_mc_msfilter(struct sock *sk, struct ip_msfilter *msf, int ifindex)
 	pmc->sfmode = msf->imsf_fmode;
 	err = 0;
 done:
-	rtnl_shunlock();
+	rtnl_unlock();
 	if (leavegroup)
 		err = ip_mc_leave_group(sk, &imr);
 	return err;
@@ -2050,7 +2050,7 @@ int ip_mc_msfget(struct sock *sk, struct ip_msfilter *msf,
 	if (!MULTICAST(addr))
 		return -EINVAL;
 
-	rtnl_shlock();
+	rtnl_lock();
 
 	imr.imr_multiaddr.s_addr = msf->imsf_multiaddr;
 	imr.imr_address.s_addr = msf->imsf_interface;
@@ -2072,7 +2072,7 @@ int ip_mc_msfget(struct sock *sk, struct ip_msfilter *msf,
 		goto done;
 	msf->imsf_fmode = pmc->sfmode;
 	psl = pmc->sflist;
-	rtnl_shunlock();
+	rtnl_unlock();
 	if (!psl) {
 		len = 0;
 		count = 0;
@@ -2091,7 +2091,7 @@ int ip_mc_msfget(struct sock *sk, struct ip_msfilter *msf,
 		return -EFAULT;
 	return 0;
 done:
-	rtnl_shunlock();
+	rtnl_unlock();
 	return err;
 }
 
@@ -2112,7 +2112,7 @@ int ip_mc_gsfget(struct sock *sk, struct group_filter *gsf,
 	if (!MULTICAST(addr))
 		return -EINVAL;
 
-	rtnl_shlock();
+	rtnl_lock();
 
 	err = -EADDRNOTAVAIL;
 
@@ -2125,7 +2125,7 @@ int ip_mc_gsfget(struct sock *sk, struct group_filter *gsf,
 		goto done;
 	gsf->gf_fmode = pmc->sfmode;
 	psl = pmc->sflist;
-	rtnl_shunlock();
+	rtnl_unlock();
 	count = psl ? psl->sl_count : 0;
 	copycount = count < gsf->gf_numsrc ? count : gsf->gf_numsrc;
 	gsf->gf_numsrc = count;
@@ -2146,7 +2146,7 @@ int ip_mc_gsfget(struct sock *sk, struct group_filter *gsf,
 	}
 	return 0;
 done:
-	rtnl_shunlock();
+	rtnl_unlock();
 	return err;
 }
 

net/ipv4/ipconfig.c

@@ -186,7 +186,7 @@ static int __init ic_open_devs(void)
 	unsigned short oflags;
 
 	last = &ic_first_dev;
-	rtnl_shlock();
+	rtnl_lock();
 
 	/* bring loopback device up first */
 	if (dev_change_flags(&loopback_dev, loopback_dev.flags | IFF_UP) < 0)
@@ -215,7 +215,7 @@ static int __init ic_open_devs(void)
 				continue;
 			}
 			if (!(d = kmalloc(sizeof(struct ic_device), GFP_KERNEL))) {
-				rtnl_shunlock();
+				rtnl_unlock();
 				return -1;
 			}
 			d->dev = dev;
@@ -232,7 +232,7 @@ static int __init ic_open_devs(void)
 				dev->name, able, d->xid));
 		}
 	}
-	rtnl_shunlock();
+	rtnl_unlock();
 
 	*last = NULL;
 
@@ -251,7 +251,7 @@ static void __init ic_close_devs(void)
 	struct ic_device *d, *next;
 	struct net_device *dev;
 
-	rtnl_shlock();
+	rtnl_lock();
 	next = ic_first_dev;
 	while ((d = next)) {
 		next = d->next;
@@ -262,7 +262,7 @@ static void __init ic_close_devs(void)
 		}
 		kfree(d);
 	}
-	rtnl_shunlock();
+	rtnl_unlock();
 }
 
 /*