[PATCH net-next v2 03/14] nexthop: Add a dedicated flag for multipath next-hop groups

[Petr Machata]

With the introduction of resilient nexthop groups, there will be two types
of multipath groups: the current hash-threshold "mpath" ones, and resilient
groups. Both are multipath, but to determine the fact, the system needs to
consider two flags. This might prove costly in the datapath. Therefore,
introduce a new flag, that should be set for next-hop groups that have more
than one nexthop, and should be considered multipath.

Signed-off-by: Petr Machata <pe...@nvidia.com>
Reviewed-by: Ido Schimmel <ido...@nvidia.com>
Reviewed-by: David Ahern <dsah...@kernel.org>
---

Notes:
    v1 (changes since RFC):
    - This patch is new

 include/net/nexthop.h | 7 ++++---
 net/ipv4/nexthop.c    | 5 ++++-
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/include/net/nexthop.h b/include/net/nexthop.h
index 7bc057aee40b..5062c2c08e2b 100644
--- a/include/net/nexthop.h
+++ b/include/net/nexthop.h
@@ -80,6 +80,7 @@ struct nh_grp_entry {
 struct nh_group {
        struct nh_group         *spare; /* spare group for removals */
        u16                     num_nh;
+       bool                    is_multipath;
        bool                    mpath;
        bool                    fdb_nh;
        bool                    has_v4;
@@ -212,7 +213,7 @@ static inline bool nexthop_is_multipath(const struct 
nexthop *nh)
                struct nh_group *nh_grp;
 
                nh_grp = rcu_dereference_rtnl(nh->nh_grp);
-               return nh_grp->mpath;
+               return nh_grp->is_multipath;
        }
        return false;
 }
@@ -227,7 +228,7 @@ static inline unsigned int nexthop_num_path(const struct 
nexthop *nh)
                struct nh_group *nh_grp;
 
                nh_grp = rcu_dereference_rtnl(nh->nh_grp);
-               if (nh_grp->mpath)
+               if (nh_grp->is_multipath)
                        rc = nh_grp->num_nh;
        }
 
@@ -308,7 +309,7 @@ struct fib_nh_common *nexthop_fib_nhc(struct nexthop *nh, 
int nhsel)
                struct nh_group *nh_grp;
 
                nh_grp = rcu_dereference_rtnl(nh->nh_grp);
-               if (nh_grp->mpath) {
+               if (nh_grp->is_multipath) {
                        nh = nexthop_mpath_select(nh_grp, nhsel);
                        if (!nh)
                                return NULL;
diff --git a/net/ipv4/nexthop.c b/net/ipv4/nexthop.c
index 69c8b50a936e..56c54d0fbacc 100644
--- a/net/ipv4/nexthop.c
+++ b/net/ipv4/nexthop.c
@@ -967,6 +967,7 @@ static void remove_nh_grp_entry(struct net *net, struct 
nh_grp_entry *nhge,
        }
 
        newg->has_v4 = false;
+       newg->is_multipath = nhg->is_multipath;
        newg->mpath = nhg->mpath;
        newg->fdb_nh = nhg->fdb_nh;
        newg->num_nh = nhg->num_nh;
@@ -1488,8 +1489,10 @@ static struct nexthop *nexthop_create_group(struct net 
*net,
                nhg->nh_entries[i].nh_parent = nh;
        }
 
-       if (cfg->nh_grp_type == NEXTHOP_GRP_TYPE_MPATH)
+       if (cfg->nh_grp_type == NEXTHOP_GRP_TYPE_MPATH) {
                nhg->mpath = 1;
+               nhg->is_multipath = true;
+       }
 
        WARN_ON_ONCE(nhg->mpath != 1);
 
-- 
2.26.2