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

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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 d27b9c40db ("ipv6: Preallocate nhc_pcpu_rth_output in
    ip6_route_info_create().")
  * commit 5720a328c3 ("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>
This commit is contained in:
Kuniyuki Iwashima 2025-05-15 19:27:23 -07:00 committed by Jakub Kicinski
parent d465bd07d1
commit 002dba13c8
2 changed files with 7 additions and 37 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

10
net/ipv4/fib_semantics.c
View file

@ -617,12 +617,10 @@ int fib_nh_common_init(struct net *net, struct fib_nh_common *nhc,
{ {
int err; int err;
if (!nhc->nhc_pcpu_rth_output) { nhc->nhc_pcpu_rth_output = alloc_percpu_gfp(struct rtable __rcu *,
nhc->nhc_pcpu_rth_output = alloc_percpu_gfp(struct rtable __rcu *, gfp_flags);
gfp_flags); if (!nhc->nhc_pcpu_rth_output)
if (!nhc->nhc_pcpu_rth_output) return -ENOMEM;
return -ENOMEM;
}
if (encap) { if (encap) {
struct lwtunnel_state *lwtstate; struct lwtunnel_state *lwtstate;

34
net/ipv6/route.c
View file

@ -3674,12 +3674,10 @@ int fib6_nh_init(struct net *net, struct fib6_nh *fib6_nh,
goto out; goto out;
pcpu_alloc: pcpu_alloc:
fib6_nh->rt6i_pcpu = alloc_percpu_gfp(struct rt6_info *, gfp_flags);
if (!fib6_nh->rt6i_pcpu) { if (!fib6_nh->rt6i_pcpu) {
fib6_nh->rt6i_pcpu = alloc_percpu_gfp(struct rt6_info *, gfp_flags); err = -ENOMEM;
if (!fib6_nh->rt6i_pcpu) { goto out;
err = -ENOMEM;
goto out;
}
} }
fib6_nh->fib_nh_dev = dev; 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, static struct fib6_info *ip6_route_info_create(struct fib6_config *cfg,
gfp_t gfp_flags, gfp_t gfp_flags,
struct netlink_ext_ack *extack) struct netlink_ext_ack *extack)
@ -3794,12 +3774,6 @@ static struct fib6_info *ip6_route_info_create(struct fib6_config *cfg,
goto free; 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) if (cfg->fc_flags & RTF_ADDRCONF)
rt->dst_nocount = true; 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; rt->fib6_src.plen = cfg->fc_src_len;
#endif #endif
return rt; return rt;
free_metrics:
ip_fib_metrics_put(rt->fib6_metrics);
free: free:
kfree(rt); kfree(rt);
err: err: