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authorDaniel Borkmann <daniel@iogearbox.net>2019-05-14 01:18:55 +0200
committerAlexei Starovoitov <ast@kernel.org>2019-05-14 10:47:29 -0700
commitc6110222c6f49ea68169f353565eb865488a8619 (patch)
tree181de3f33b1e298789b1827b0103d6304f532a86 /kernel
parent2474c62898c63f8bb122ffda2cd93fdaad55603a (diff)
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bpf: add map_lookup_elem_sys_only for lookups from syscall side
Add a callback map_lookup_elem_sys_only() that map implementations could use over map_lookup_elem() from system call side in case the map implementation needs to handle the latter differently than from the BPF data path. If map_lookup_elem_sys_only() is set, this will be preferred pick for map lookups out of user space. This hook is used in a follow-up fix for LRU map, but once development window opens, we can convert other map types from map_lookup_elem() (here, the one called upon BPF_MAP_LOOKUP_ELEM cmd is meant) over to use the callback to simplify and clean up the latter. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/bpf/syscall.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index ad3ccf82f31d..cb5440b02e82 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -808,7 +808,10 @@ static int map_lookup_elem(union bpf_attr *attr)
err = map->ops->map_peek_elem(map, value);
} else {
rcu_read_lock();
- ptr = map->ops->map_lookup_elem(map, key);
+ if (map->ops->map_lookup_elem_sys_only)
+ ptr = map->ops->map_lookup_elem_sys_only(map, key);
+ else
+ ptr = map->ops->map_lookup_elem(map, key);
if (IS_ERR(ptr)) {
err = PTR_ERR(ptr);
} else if (!ptr) {