On Wed, Oct 20, 2021 at 09:03:18PM +0100, Pavel Begunkov wrote:

+/**
+ * percpu_ref_tryget_live_rcu - same as percpu_ref_tryget_live() but the
+ * caller is responsible for taking RCU.
+ *
+ * This function is safe to call as long as @ref is between init and exit.
+ */
+static inline bool percpu_ref_tryget_live_rcu(struct percpu_ref *ref)
+{
+	unsigned long __percpu *percpu_count;
+	bool ret = false;
+
+	if (likely(__ref_is_percpu(ref, &percpu_count))) {
+		this_cpu_inc(*percpu_count);
+		ret = true;
+	} else if (!(ref->percpu_count_ptr & __PERCPU_REF_DEAD)) {
+		ret = atomic_long_inc_not_zero(&ref->data->count);
+	}
+	return ret;
+}

Can we please add rcu_read_lock_held() assertion? Other than that, looks
fine to me.

Thanks.

-- 
tejun