From: David Ahern <dsah...@gmail.com>

Using iproute2 to create a bridge and add 4094 vlans to it can take from
2 to 3 *minutes*. The reason is the extraneous call to ll_name_to_index.
ll_name_to_index results in an ioctl(SIOCGIFINDEX) call which in turn
invokes dev_load. If the index does not exist, which it won't when
creating a new link, dev_load calls modprobe twice -- once for
netdev-NAME and again for NAME. This is unnecessary overhead for each
link create.

When ip link is invoked for a new device, there is no reason to
call ll_name_to_index for the new device. With this patch, creating
a bridge and adding 4094 vlans takes less than 3 *seconds*.

Signed-off-by: David Ahern <dsah...@gmail.com>
---
 ip/ip_common.h    |  3 ++-
 ip/iplink.c       | 22 +++++++++++++---------
 ip/iplink_vxcan.c |  3 ++-
 ip/link_veth.c    |  3 ++-
 4 files changed, 19 insertions(+), 12 deletions(-)

diff --git a/ip/ip_common.h b/ip/ip_common.h
index 1b89795caa58..67f413474631 100644
--- a/ip/ip_common.h
+++ b/ip/ip_common.h
@@ -132,7 +132,8 @@ struct link_util {
 
 struct link_util *get_link_kind(const char *kind);
 
-int iplink_parse(int argc, char **argv, struct iplink_req *req, char **type);
+int iplink_parse(int argc, char **argv, struct iplink_req *req,
+                char **type, bool is_add_cmd);
 
 /* iplink_bridge.c */
 void br_dump_bridge_id(const struct ifla_bridge_id *id, char *buf, size_t len);
diff --git a/ip/iplink.c b/ip/iplink.c
index e6bb4493120e..c8bf49ed3d24 100644
--- a/ip/iplink.c
+++ b/ip/iplink.c
@@ -571,7 +571,8 @@ static int iplink_parse_vf(int vf, int *argcp, char 
***argvp,
        return 0;
 }
 
-int iplink_parse(int argc, char **argv, struct iplink_req *req, char **type)
+int iplink_parse(int argc, char **argv, struct iplink_req *req, char **type,
+                bool is_add_cmd)
 {
        char *name = NULL;
        char *dev = NULL;
@@ -610,7 +611,8 @@ int iplink_parse(int argc, char **argv, struct iplink_req 
*req, char **type)
                        name = *argv;
                        if (!dev) {
                                dev = name;
-                               dev_index = ll_name_to_index(dev);
+                               if (!is_add_cmd)
+                                       dev_index = ll_name_to_index(dev);
                        }
                } else if (strcmp(*argv, "index") == 0) {
                        NEXT_ARG();
@@ -919,7 +921,8 @@ int iplink_parse(int argc, char **argv, struct iplink_req 
*req, char **type)
                        if (check_ifname(*argv))
                                invarg("\"dev\" not a valid ifname", *argv);
                        dev = *argv;
-                       dev_index = ll_name_to_index(dev);
+                       if (!is_add_cmd)
+                               dev_index = ll_name_to_index(dev);
                }
                argc--; argv++;
        }
@@ -1011,7 +1014,8 @@ int iplink_parse(int argc, char **argv, struct iplink_req 
*req, char **type)
        return ret;
 }
 
-static int iplink_modify(int cmd, unsigned int flags, int argc, char **argv)
+static int iplink_modify(int cmd, unsigned int flags, int argc, char **argv,
+                        bool is_add_cmd)
 {
        char *type = NULL;
        struct iplink_req req = {
@@ -1022,7 +1026,7 @@ static int iplink_modify(int cmd, unsigned int flags, int 
argc, char **argv)
        };
        int ret;
 
-       ret = iplink_parse(argc, argv, &req, &type);
+       ret = iplink_parse(argc, argv, &req, &type, is_add_cmd);
        if (ret < 0)
                return ret;
 
@@ -1630,18 +1634,18 @@ int do_iplink(int argc, char **argv)
                if (matches(*argv, "add") == 0)
                        return iplink_modify(RTM_NEWLINK,
                                             NLM_F_CREATE|NLM_F_EXCL,
-                                            argc-1, argv+1);
+                                            argc-1, argv+1, true);
                if (matches(*argv, "set") == 0 ||
                    matches(*argv, "change") == 0)
                        return iplink_modify(RTM_NEWLINK, 0,
-                                            argc-1, argv+1);
+                                            argc-1, argv+1, false);
                if (matches(*argv, "replace") == 0)
                        return iplink_modify(RTM_NEWLINK,
                                             NLM_F_CREATE|NLM_F_REPLACE,
-                                            argc-1, argv+1);
+                                            argc-1, argv+1, false);
                if (matches(*argv, "delete") == 0)
                        return iplink_modify(RTM_DELLINK, 0,
-                                            argc-1, argv+1);
+                                            argc-1, argv+1, false);
        } else {
 #if IPLINK_IOCTL_COMPAT
                if (matches(*argv, "set") == 0)
diff --git a/ip/iplink_vxcan.c b/ip/iplink_vxcan.c
index 8b08c9a70c65..e30a784d9851 100644
--- a/ip/iplink_vxcan.c
+++ b/ip/iplink_vxcan.c
@@ -56,7 +56,8 @@ static int vxcan_parse_opt(struct link_util *lu, int argc, 
char **argv,
 
        n->nlmsg_len += sizeof(struct ifinfomsg);
 
-       err = iplink_parse(argc - 1, argv + 1, (struct iplink_req *)n, &type);
+       err = iplink_parse(argc - 1, argv + 1, (struct iplink_req *)n, &type,
+                          false);
        if (err < 0)
                return err;
 
diff --git a/ip/link_veth.c b/ip/link_veth.c
index 33e8f2b102e7..68823931c0ec 100644
--- a/ip/link_veth.c
+++ b/ip/link_veth.c
@@ -54,7 +54,8 @@ static int veth_parse_opt(struct link_util *lu, int argc, 
char **argv,
 
        n->nlmsg_len += sizeof(struct ifinfomsg);
 
-       err = iplink_parse(argc - 1, argv + 1, (struct iplink_req *)n, &type);
+       err = iplink_parse(argc - 1, argv + 1, (struct iplink_req *)n, &type,
+                          false);
        if (err < 0)
                return err;
 
-- 
2.11.0

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