bpf: don't rely on the verifier lock for metadata_dst allocation

bpf_skb_set_tunnel_*() functions require allocation of per-cpu
metadata_dst.  The allocation happens upon verification of the
first program using those helpers.  In preparation for removing
the verifier lock, use cmpxchg() to make sure we only allocate
the metadata_dsts once.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Simon Horman <simon.horman@netronome.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Jakub Kicinski
2017-10-09 10:30:14 -07:00
committed by David S. Miller
parent c9c35995bc
commit d66f2b91f9
3 changed files with 26 additions and 7 deletions

View File

@@ -87,6 +87,7 @@ static inline int skb_metadata_dst_cmp(const struct sk_buff *skb_a,
void metadata_dst_free(struct metadata_dst *);
struct metadata_dst *metadata_dst_alloc(u8 optslen, enum metadata_type type,
gfp_t flags);
void metadata_dst_free_percpu(struct metadata_dst __percpu *md_dst);
struct metadata_dst __percpu *
metadata_dst_alloc_percpu(u8 optslen, enum metadata_type type, gfp_t flags);