ipv6: Revert two per-cpu var allocation for RTM_NEWROUTE.

These two commits preallocated two per-cpu variables in
ip6_route_info_create() as fib_nh_common_init() and fib6_nh_init()
were expected to be called under RCU.

  * commit d27b9c40dbd6 ("ipv6: Preallocate nhc_pcpu_rth_output in
    ip6_route_info_create().")
  * commit 5720a328c3e9 ("ipv6: Preallocate rt->fib6_nh->rt6i_pcpu in
    ip6_route_info_create().")

Now these functions can be called without RCU and can use GFP_KERNEL.

Let's revert the commits.

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://patch.msgid.link/20250516022759.44392-8-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
index dabe2b7044ab8eac4d8f217b53d9832b3b79f260..d643bd1a0d9df46e2c946ce2696f73ebe8c40b14 100644 (file)
--- a/net/ipv4/fib_semantics.c
+++ b/net/ipv4/fib_semantics.c
@@ -617,12 +617,10 @@ int fib_nh_common_init(struct net *net, struct fib_nh_common *nhc,
 {
        int err;
 
-       if (!nhc->nhc_pcpu_rth_output) {
-               nhc->nhc_pcpu_rth_output = alloc_percpu_gfp(struct rtable __rcu *,
-                                                           gfp_flags);
-               if (!nhc->nhc_pcpu_rth_output)
-                       return -ENOMEM;
-       }
+       nhc->nhc_pcpu_rth_output = alloc_percpu_gfp(struct rtable __rcu *,
+                                                   gfp_flags);
+       if (!nhc->nhc_pcpu_rth_output)
+               return -ENOMEM;
 
        if (encap) {
                struct lwtunnel_state *lwtstate;

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index dda913ebd2d3ee4f0581f48a8369f4ce692d1f26..0143262094b0a88d7f5889c292ad0a1b17b01753 100644 (file)
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -3674,12 +3674,10 @@ int fib6_nh_init(struct net *net, struct fib6_nh *fib6_nh,
                goto out;
 
 pcpu_alloc:
+       fib6_nh->rt6i_pcpu = alloc_percpu_gfp(struct rt6_info *, gfp_flags);
        if (!fib6_nh->rt6i_pcpu) {
-               fib6_nh->rt6i_pcpu = alloc_percpu_gfp(struct rt6_info *, gfp_flags);
-               if (!fib6_nh->rt6i_pcpu) {
-                       err = -ENOMEM;
-                       goto out;
-               }
+               err = -ENOMEM;
+               goto out;
        }
 
        fib6_nh->fib_nh_dev = dev;
@@ -3739,24 +3737,6 @@ void fib6_nh_release_dsts(struct fib6_nh *fib6_nh)
        }
 }
 
-static int fib6_nh_prealloc_percpu(struct fib6_nh *fib6_nh, gfp_t gfp_flags)
-{
-       struct fib_nh_common *nhc = &fib6_nh->nh_common;
-
-       fib6_nh->rt6i_pcpu = alloc_percpu_gfp(struct rt6_info *, gfp_flags);
-       if (!fib6_nh->rt6i_pcpu)
-               return -ENOMEM;
-
-       nhc->nhc_pcpu_rth_output = alloc_percpu_gfp(struct rtable __rcu *,
-                                                   gfp_flags);
-       if (!nhc->nhc_pcpu_rth_output) {
-               free_percpu(fib6_nh->rt6i_pcpu);
-               return -ENOMEM;
-       }
-
-       return 0;
-}
-
 static struct fib6_info *ip6_route_info_create(struct fib6_config *cfg,
                                               gfp_t gfp_flags,
                                               struct netlink_ext_ack *extack)
@@ -3794,12 +3774,6 @@ static struct fib6_info *ip6_route_info_create(struct fib6_config *cfg,
                goto free;
        }
 
-       if (!cfg->fc_nh_id) {
-               err = fib6_nh_prealloc_percpu(&rt->fib6_nh[0], gfp_flags);
-               if (err)
-                       goto free_metrics;
-       }
-
        if (cfg->fc_flags & RTF_ADDRCONF)
                rt->dst_nocount = true;
 
@@ -3824,8 +3798,6 @@ static struct fib6_info *ip6_route_info_create(struct fib6_config *cfg,
        rt->fib6_src.plen = cfg->fc_src_len;
 #endif
        return rt;
-free_metrics:
-       ip_fib_metrics_put(rt->fib6_metrics);
 free:
        kfree(rt);
 err: