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| author | Alexei Starovoitov <ast@kernel.org> | 2020-06-30 07:33:39 +0300 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2020-07-01 18:07:13 +0300 |
| commit | bba1dc0b55ac462d24ed1228ad49800c238cd6d7 (patch) | |
| tree | d83554930260fe70393ea2d74734357577035dce /kernel/bpf/ringbuf.c | |
| parent | 8c18311067d0f0d5f332b9e1f3859eb15e23332d (diff) | |
| download | linux-bba1dc0b55ac462d24ed1228ad49800c238cd6d7.tar.xz | |
bpf: Remove redundant synchronize_rcu.
bpf_free_used_maps() or close(map_fd) will trigger map_free callback.
bpf_free_used_maps() is called after bpf prog is no longer executing:
bpf_prog_put->call_rcu->bpf_prog_free->bpf_free_used_maps.
Hence there is no need to call synchronize_rcu() to protect map elements.
Note that hash_of_maps and array_of_maps update/delete inner maps via
sys_bpf() that calls maybe_wait_bpf_programs() and synchronize_rcu().
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Paul E. McKenney <paulmck@kernel.org>
Link: https://lore.kernel.org/bpf/20200630043343.53195-2-alexei.starovoitov@gmail.com
Diffstat (limited to 'kernel/bpf/ringbuf.c')
| -rw-r--r-- | kernel/bpf/ringbuf.c | 7 |
1 files changed, 0 insertions, 7 deletions
diff --git a/kernel/bpf/ringbuf.c b/kernel/bpf/ringbuf.c index dbf37aff4827..13a8d3967e07 100644 --- a/kernel/bpf/ringbuf.c +++ b/kernel/bpf/ringbuf.c @@ -215,13 +215,6 @@ static void ringbuf_map_free(struct bpf_map *map) { struct bpf_ringbuf_map *rb_map; - /* at this point bpf_prog->aux->refcnt == 0 and this map->refcnt == 0, - * so the programs (can be more than one that used this map) were - * disconnected from events. Wait for outstanding critical sections in - * these programs to complete - */ - synchronize_rcu(); - rb_map = container_of(map, struct bpf_ringbuf_map, map); bpf_ringbuf_free(rb_map->rb); kfree(rb_map); |