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-rw-r--r--kernel/bpf/syscall.c11
1 files changed, 11 insertions, 0 deletions
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 228f962..23eb205 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -680,6 +680,17 @@ struct bpf_prog *bpf_prog_add(struct bpf_prog *prog, int i)
}
EXPORT_SYMBOL_GPL(bpf_prog_add);
+void bpf_prog_sub(struct bpf_prog *prog, int i)
+{
+ /* Only to be used for undoing previous bpf_prog_add() in some
+ * error path. We still know that another entity in our call
+ * path holds a reference to the program, thus atomic_sub() can
+ * be safely used in such cases!
+ */
+ WARN_ON(atomic_sub_return(i, &prog->aux->refcnt) == 0);
+}
+EXPORT_SYMBOL_GPL(bpf_prog_sub);
+
struct bpf_prog *bpf_prog_inc(struct bpf_prog *prog)
{
return bpf_prog_add(prog, 1);
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