sparse and devinet_ioctl

["Aneesh Kumar" <aneesh.kumar@gmail.com>]

How do i make sure i can call devinet_ioctl from kernel without having
a sparse warning.

The call i want to use was SIOCGIFADDR

Right now i am patching it as below

_devinet_ioctl(SIOCGIFADDR, &ifr)

Is this the correct way ? But then I don't want to patch any core
kernel files. In that case how will i achieve the results.


-aneesh

diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index 54419b2..e8e9eaa 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -532,11 +532,10 @@ static __inline__ int inet_abc_len(u32 a
 }
 
 
-int devinet_ioctl(unsigned int cmd, void __user *arg)
+int _devinet_ioctl(unsigned int cmd,  struct ifreq *ifr)
 {
-	struct ifreq ifr;
 	struct sockaddr_in sin_orig;
-	struct sockaddr_in *sin = (struct sockaddr_in *)&ifr.ifr_addr;
+	struct sockaddr_in *sin = (struct sockaddr_in *)&ifr->ifr_addr;
 	struct in_device *in_dev;
 	struct in_ifaddr **ifap = NULL;
 	struct in_ifaddr *ifa = NULL;
@@ -545,23 +544,17 @@ int devinet_ioctl(unsigned int cmd, void
 	int ret = -EFAULT;
 	int tryaddrmatch = 0;
 
-	/*
-	 *	Fetch the caller's info block into kernel space
-	 */
-
-	if (copy_from_user(&ifr, arg, sizeof(struct ifreq)))
-		goto out;
-	ifr.ifr_name[IFNAMSIZ - 1] = 0;
+	ifr->ifr_name[IFNAMSIZ - 1] = 0;
 
 	/* save original address for comparison */
 	memcpy(&sin_orig, sin, sizeof(*sin));
 
-	colon = strchr(ifr.ifr_name, ':');
+	colon = strchr(ifr->ifr_name, ':');
 	if (colon)
 		*colon = 0;
 
 #ifdef CONFIG_KMOD
-	dev_load(ifr.ifr_name);
+	dev_load(ifr->ifr_name);
 #endif
 
 	switch(cmd) {
@@ -602,7 +595,7 @@ #endif
 	rtnl_lock();
 
 	ret = -ENODEV;
-	if ((dev = __dev_get_by_name(ifr.ifr_name)) == NULL)
+	if ((dev = __dev_get_by_name(ifr->ifr_name)) == NULL)
 		goto done;
 
 	if (colon)
@@ -617,7 +610,7 @@ #endif
 			   This is checked above. */
 			for (ifap = &in_dev->ifa_list; (ifa = *ifap) != NULL;
 			     ifap = &ifa->ifa_next) {
-				if (!strcmp(ifr.ifr_name, ifa->ifa_label) &&
+				if (!strcmp(ifr->ifr_name, ifa->ifa_label) &&
 				    sin_orig.sin_addr.s_addr ==
 							ifa->ifa_address) {
 					break; /* found */
@@ -630,7 +623,7 @@ #endif
 		if (!ifa) {
 			for (ifap = &in_dev->ifa_list; (ifa = *ifap) != NULL;
 			     ifap = &ifa->ifa_next)
-				if (!strcmp(ifr.ifr_name, ifa->ifa_label))
+				if (!strcmp(ifr->ifr_name, ifa->ifa_label))
 					break;
 		}
 	}
@@ -662,11 +655,11 @@ #endif
 			if (!ifa)
 				break;
 			ret = 0;
-			if (!(ifr.ifr_flags & IFF_UP))
+			if (!(ifr->ifr_flags & IFF_UP))
 				inet_del_ifa(in_dev, ifap, 1);
 			break;
 		}
-		ret = dev_change_flags(dev, ifr.ifr_flags);
+		ret = dev_change_flags(dev, ifr->ifr_flags);
 		break;
 
 	case SIOCSIFADDR:	/* Set interface address (and family) */
@@ -679,7 +672,7 @@ #endif
 			if ((ifa = inet_alloc_ifa()) == NULL)
 				break;
 			if (colon)
-				memcpy(ifa->ifa_label, ifr.ifr_name, IFNAMSIZ);
+				memcpy(ifa->ifa_label, ifr->ifr_name, IFNAMSIZ);
 			else
 				memcpy(ifa->ifa_label, dev->name, IFNAMSIZ);
 		} else {
@@ -767,9 +760,26 @@ out:
 	return ret;
 rarok:
 	rtnl_unlock();
-	ret = copy_to_user(arg, &ifr, sizeof(struct ifreq)) ? -EFAULT : 0;
 	goto out;
 }
+int devinet_ioctl(unsigned int cmd, void __user *arg)
+{
+	struct ifreq ifr;
+	int ret;
+
+	/*
+	 *	Fetch the caller's info block into kernel space
+	 */
+
+	if (copy_from_user(&ifr, arg, sizeof(struct ifreq)))
+		return -EFAULT;
+
+	if ((ret = _devinet_ioctl(cmd, &ifr)) == 0 ) {
+		ret = copy_to_user(arg, &ifr, sizeof(struct ifreq)) ? -EFAULT : 0;
+	}
+	return ret;
+
+}
 
 static int inet_gifconf(struct net_device *dev, char __user *buf, int len)
 {