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authorAlexei Starovoitov <ast@kernel.org>2020-06-30 07:33:39 +0300
committerAlexei Starovoitov <ast@kernel.org>2020-07-01 18:07:13 +0300
commitbba1dc0b55ac462d24ed1228ad49800c238cd6d7 (patch)
treed83554930260fe70393ea2d74734357577035dce /kernel/bpf/stackmap.c
parent8c18311067d0f0d5f332b9e1f3859eb15e23332d (diff)
downloadlinux-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/stackmap.c')
-rw-r--r--kernel/bpf/stackmap.c3
1 files changed, 0 insertions, 3 deletions
diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c
index 27dc9b1b08a5..071f98d0f7c6 100644
--- a/kernel/bpf/stackmap.c
+++ b/kernel/bpf/stackmap.c
@@ -604,9 +604,6 @@ static void stack_map_free(struct bpf_map *map)
{
struct bpf_stack_map *smap = container_of(map, struct bpf_stack_map, map);
- /* wait for bpf programs to complete before freeing stack map */
- synchronize_rcu();
-
bpf_map_area_free(smap->elems);
pcpu_freelist_destroy(&smap->freelist);
bpf_map_area_free(smap);