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ipv6: Preallocate nhc_pcpu_rth_output in ip6_route_info_create().

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ip6_route_info_create_nh() will be called under RCU.

It calls fib_nh_common_init() and allocates nhc->nhc_pcpu_rth_output.

As with the reason for rt->fib6_nh->rt6i_pcpu, we want to avoid
GFP_ATOMIC allocation for nhc->nhc_pcpu_rth_output under RCU.

Let's preallocate it in ip6_route_info_create().

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://patch.msgid.link/20250418000443.43734-9-kuniyu@amazon.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
This commit is contained in:
Kuniyuki Iwashima 2025-04-17 17:03:49 -07:00 committed by Paolo Abeni
parent 5720a328c3
commit d27b9c40db
2 changed files with 15 additions and 4 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

2
net/ipv4/fib_semantics.c
View file

@ -617,10 +617,12 @@ 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;
}
if (encap) {
struct lwtunnel_state *lwtstate;

9
net/ipv6/route.c
View file

@ -3732,10 +3732,19 @@ 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;
}