bpf: Factor out bpf_spin_lock into helpers.

Move ____bpf_spin_lock/unlock into helpers to make it more clear
that quadruple underscore bpf_spin_lock/unlock are irqsave/restore variants.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/20210715005417.78572-3-alexei.starovoitov@gmail.com

kernel/bpf/helpers.c

@@ -289,13 +289,18 @@ static inline void __bpf_spin_unlock(struct bpf_spin_lock *lock)
 
 static DEFINE_PER_CPU(unsigned long, irqsave_flags);
 
-notrace BPF_CALL_1(bpf_spin_lock, struct bpf_spin_lock *, lock)
+static inline void __bpf_spin_lock_irqsave(struct bpf_spin_lock *lock)
 {
 	unsigned long flags;
 
 	local_irq_save(flags);
 	__bpf_spin_lock(lock);
 	__this_cpu_write(irqsave_flags, flags);
+}
+
+notrace BPF_CALL_1(bpf_spin_lock, struct bpf_spin_lock *, lock)
+{
+	__bpf_spin_lock_irqsave(lock);
 	return 0;
 }
 
@@ -306,13 +311,18 @@ const struct bpf_func_proto bpf_spin_lock_proto = {
 	.arg1_type	= ARG_PTR_TO_SPIN_LOCK,
 };
 
-notrace BPF_CALL_1(bpf_spin_unlock, struct bpf_spin_lock *, lock)
+static inline void __bpf_spin_unlock_irqrestore(struct bpf_spin_lock *lock)
 {
 	unsigned long flags;
 
 	flags = __this_cpu_read(irqsave_flags);
 	__bpf_spin_unlock(lock);
 	local_irq_restore(flags);
+}
+
+notrace BPF_CALL_1(bpf_spin_unlock, struct bpf_spin_lock *, lock)
+{
+	__bpf_spin_unlock_irqrestore(lock);
 	return 0;
 }
 
@@ -333,9 +343,9 @@ void copy_map_value_locked(struct bpf_map *map, void *dst, void *src,
 	else
 		lock = dst + map->spin_lock_off;
 	preempt_disable();
-	____bpf_spin_lock(lock);
+	__bpf_spin_lock_irqsave(lock);
 	copy_map_value(map, dst, src);
-	____bpf_spin_unlock(lock);
+	__bpf_spin_unlock_irqrestore(lock);
 	preempt_enable();
 }