bpf: {cpu,dev}map: Change various functions return type from int to void

The functions bq_enqueue(), bq_flush_to_queue(), and bq_xmit_all() in
{cpu,dev}map.c always return zero. Changing the return type from int
to void makes the code easier to follow.
Suggested-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/20200901083928.6199-1-bjorn.topel@gmail.com

kernel/bpf/cpumap.c

@@ -79,8 +79,6 @@ struct bpf_cpu_map {
 
 static DEFINE_PER_CPU(struct list_head, cpu_map_flush_list);
 
-static int bq_flush_to_queue(struct xdp_bulk_queue *bq);
-
 static struct bpf_map *cpu_map_alloc(union bpf_attr *attr)
 {
 	u32 value_size = attr->value_size;
@@ -670,7 +668,7 @@ const struct bpf_map_ops cpu_map_ops = {
 	.map_btf_id		= &cpu_map_btf_id,
 };
 
-static int bq_flush_to_queue(struct xdp_bulk_queue *bq)
+static void bq_flush_to_queue(struct xdp_bulk_queue *bq)
 {
 	struct bpf_cpu_map_entry *rcpu = bq->obj;
 	unsigned int processed = 0, drops = 0;
@@ -679,7 +677,7 @@ static int bq_flush_to_queue(struct xdp_bulk_queue *bq)
 	int i;
 
 	if (unlikely(!bq->count))
-		return 0;
+		return;
 
 	q = rcpu->queue;
 	spin_lock(&q->producer_lock);
@@ -702,13 +700,12 @@ static int bq_flush_to_queue(struct xdp_bulk_queue *bq)
 
 	/* Feedback loop via tracepoints */
 	trace_xdp_cpumap_enqueue(rcpu->map_id, processed, drops, to_cpu);
-	return 0;
 }
 
 /* Runs under RCU-read-side, plus in softirq under NAPI protection.
  * Thus, safe percpu variable access.
  */
-static int bq_enqueue(struct bpf_cpu_map_entry *rcpu, struct xdp_frame *xdpf)
+static void bq_enqueue(struct bpf_cpu_map_entry *rcpu, struct xdp_frame *xdpf)
 {
 	struct list_head *flush_list = this_cpu_ptr(&cpu_map_flush_list);
 	struct xdp_bulk_queue *bq = this_cpu_ptr(rcpu->bulkq);
@@ -729,8 +726,6 @@ static int bq_enqueue(struct bpf_cpu_map_entry *rcpu, struct xdp_frame *xdpf)
 
 	if (!bq->flush_node.prev)
 		list_add(&bq->flush_node, flush_list);
-
-	return 0;
 }
 
 int cpu_map_enqueue(struct bpf_cpu_map_entry *rcpu, struct xdp_buff *xdp,

kernel/bpf/devmap.c

@@ -341,14 +341,14 @@ bool dev_map_can_have_prog(struct bpf_map *map)
 	return false;
 }
 
-static int bq_xmit_all(struct xdp_dev_bulk_queue *bq, u32 flags)
+static void bq_xmit_all(struct xdp_dev_bulk_queue *bq, u32 flags)
 {
 	struct net_device *dev = bq->dev;
 	int sent = 0, drops = 0, err = 0;
 	int i;
 
 	if (unlikely(!bq->count))
-		return 0;
+		return;
 
 	for (i = 0; i < bq->count; i++) {
 		struct xdp_frame *xdpf = bq->q[i];
@@ -369,7 +369,7 @@ static int bq_xmit_all(struct xdp_dev_bulk_queue *bq, u32 flags)
 	trace_xdp_devmap_xmit(bq->dev_rx, dev, sent, drops, err);
 	bq->dev_rx = NULL;
 	__list_del_clearprev(&bq->flush_node);
-	return 0;
+	return;
 error:
 	/* If ndo_xdp_xmit fails with an errno, no frames have been
 	 * xmit'ed and it's our responsibility to them free all.
@@ -421,8 +421,8 @@ struct bpf_dtab_netdev *__dev_map_lookup_elem(struct bpf_map *map, u32 key)
 /* Runs under RCU-read-side, plus in softirq under NAPI protection.
  * Thus, safe percpu variable access.
  */
-static int bq_enqueue(struct net_device *dev, struct xdp_frame *xdpf,
-		      struct net_device *dev_rx)
+static void bq_enqueue(struct net_device *dev, struct xdp_frame *xdpf,
+		       struct net_device *dev_rx)
 {
 	struct list_head *flush_list = this_cpu_ptr(&dev_flush_list);
 	struct xdp_dev_bulk_queue *bq = this_cpu_ptr(dev->xdp_bulkq);
@@ -441,8 +441,6 @@ static int bq_enqueue(struct net_device *dev, struct xdp_frame *xdpf,
 
 	if (!bq->flush_node.prev)
 		list_add(&bq->flush_node, flush_list);
-
-	return 0;
 }
 
 static inline int __xdp_enqueue(struct net_device *dev, struct xdp_buff *xdp,
@@ -462,7 +460,8 @@ static inline int __xdp_enqueue(struct net_device *dev, struct xdp_buff *xdp,
 	if (unlikely(!xdpf))
 		return -EOVERFLOW;
 
-	return bq_enqueue(dev, xdpf, dev_rx);
+	bq_enqueue(dev, xdpf, dev_rx);
+	return 0;
 }
 
 static struct xdp_buff *dev_map_run_prog(struct net_device *dev,