[lustre-devel] [PATCH 3/5] lustre: change lnet_ipaddr_enumerate() to use for_each_netdev()

[NeilBrown]

for_each_netdev() is a more direct interface than
lnet_ipif_enumerate(), so use it instead.  Also get
address and 'up' status directly from the device.

This means we need to possible re-allocate the storage
space if there are lots of IP addresses.

However there is no need to resize the allocation down if we
over-allocated.  This is only used once, and is freed soon
after it is allocated, so that is a false optimization.

Signed-off-by: NeilBrown <neilb at suse.com>
---
 drivers/staging/lustre/lnet/lnet/config.c |   78 +++++++++++++----------------
 1 file changed, 35 insertions(+), 43 deletions(-)

diff --git a/drivers/staging/lustre/lnet/lnet/config.c b/drivers/staging/lustre/lnet/lnet/config.c
index 55ecc1998b7e..136905db2746 100644
--- a/drivers/staging/lustre/lnet/lnet/config.c
+++ b/drivers/staging/lustre/lnet/lnet/config.c
@@ -36,6 +36,7 @@
 #include <net/net_namespace.h>
 #include <linux/ctype.h>
 #include <linux/lnet/lib-lnet.h>
+#include <linux/inetdevice.h>
 
 struct lnet_text_buf {	    /* tmp struct for parsing routes */
 	struct list_head ltb_list;	/* stash on lists */
@@ -1134,66 +1135,57 @@ lnet_match_networks(char **networksp, char *ip2nets, __u32 *ipaddrs, int nip)
 static int
 lnet_ipaddr_enumerate(__u32 **ipaddrsp)
 {
-	int up;
-	__u32 netmask;
+	struct net_device *dev;
 	__u32 *ipaddrs;
-	__u32 *ipaddrs2;
+	int nalloc = 64;
 	int nip;
-	char **ifnames;
-	int nif = lnet_ipif_enumerate(&ifnames);
-	int i;
-	int rc;
 
-	if (nif <= 0)
-		return nif;
-
-	ipaddrs = kcalloc(nif, sizeof(*ipaddrs), GFP_KERNEL);
+	ipaddrs = kcalloc(nalloc, sizeof(*ipaddrs), GFP_KERNEL);
 	if (!ipaddrs) {
-		CERROR("Can't allocate ipaddrs[%d]\n", nif);
-		lnet_ipif_free_enumeration(ifnames, nif);
+		CERROR("Can't allocate ipaddrs[%d]\n", nalloc);
 		return -ENOMEM;
 	}
 
-	for (i = nip = 0; i < nif; i++) {
-		if (!strcmp(ifnames[i], "lo"))
+	rtnl_lock();
+	for_each_netdev(&init_net, dev) {
+		struct in_device *in_dev;
+
+		if (strcmp(dev->name, "lo") == 0)
 			continue;
 
-		rc = lnet_ipif_query(ifnames[i], &up, &ipaddrs[nip], &netmask);
-		if (rc) {
-			CWARN("Can't query interface %s: %d\n",
-			      ifnames[i], rc);
+		if (!(dev_get_flags(dev) & IFF_UP)) {
+			CWARN("Ignoring interface %s: it's down\n", dev->name);
 			continue;
 		}
-
-		if (!up) {
-			CWARN("Ignoring interface %s: it's down\n",
-			      ifnames[i]);
+		in_dev = __in_dev_get_rtnl(dev);
+		if (!in_dev) {
+			CWARN("Interface %s has no IPv4 status.\n", dev->name);
 			continue;
 		}
 
-		nip++;
-	}
-
-	lnet_ipif_free_enumeration(ifnames, nif);
-
-	if (nip == nif) {
-		*ipaddrsp = ipaddrs;
-	} else {
-		if (nip > 0) {
-			ipaddrs2 = kcalloc(nip, sizeof(*ipaddrs2),
-					   GFP_KERNEL);
-			if (!ipaddrs2) {
-				CERROR("Can't allocate ipaddrs[%d]\n", nip);
-				nip = -ENOMEM;
-			} else {
-				memcpy(ipaddrs2, ipaddrs,
-				       nip * sizeof(*ipaddrs));
-				*ipaddrsp = ipaddrs2;
-				rc = nip;
+		if (nip >= nalloc) {
+			__u32 *ipaddrs2;
+			nalloc += nalloc;
+			ipaddrs2 = krealloc(ipaddrs, nalloc * sizeof(*ipaddrs2),
+					    GFP_KERNEL);
+			if (ipaddrs2 == NULL) {
+				kfree(ipaddrs);
+				CERROR("Can't allocate ipaddrs[%d]\n", nalloc);
+				return -ENOMEM;
 			}
+			ipaddrs = ipaddrs2;
 		}
-		kfree(ipaddrs);
+
+		for_primary_ifa(in_dev)
+			if (strcmp(ifa->ifa_label, dev->name) == 0) {
+				ipaddrs[nip++] = ifa->ifa_local;
+				break;
+			}
+		endfor_ifa(in_dev);
 	}
+	rtnl_unlock();
+
+	*ipaddrsp = ipaddrs;
 	return nip;
 }