add kernel param to pre-allocate NICs

Orabug: 30962711

This is so that eth0, eth1, ... ethX are available for ip link rename set for certain
applications (that will not be named).

Signed-off-by: Brian Maly <[email protected]>
Reviewed-by: Saar Maoz <[email protected]>
Signed-off-by: Allen Pais<[email protected]
(cherry picked from commit dc4af8d)
This commit is cherry-picked from UEK6

Orabug: 34074776
Signed-off-by: Somasundaram Krishnasamy <[email protected]>
Reviewed-by: John Donnelly <[email protected]>

Author: Somasundaram Krishnasamy

net/core/dev.c

@@ -164,6 +164,9 @@
 #include "devmem.h"
 #include "net-sysfs.h"
 
+static int ifnames_skip = 0;
+core_param(ifnames_skip, ifnames_skip, int, 0444);
+
 static DEFINE_SPINLOCK(ptype_lock);
 struct list_head ptype_base[PTYPE_HASH_SIZE] __read_mostly;
 
@@ -1117,6 +1120,12 @@ static int __dev_alloc_name(struct net *net, const char *name, char *res)
 	if (!inuse)
 		return -ENOMEM;
 
+	if (ifnames_skip) {
+		int j;
+		for (j = 0; j < ifnames_skip && j < max_netdevices; j++)
+			set_bit(j, inuse);
+	}
+
 	for_each_netdev(net, d) {
 		struct netdev_name_node *name_node;