From e1d3e7635f3fd22ec216805a22f63e8002863af8 Mon Sep 17 00:00:00 2001
From: "Jason A. Donenfeld" <Jason@zx2c4.com>
Date: Fri, 29 Nov 2019 04:47:27 +0100
Subject: device: prepare skb_list_walk_safe for upstreaming

---
 src/device.c | 6 +++---
 src/device.h | 8 ++++++++
 src/send.c   | 8 ++------
 3 files changed, 13 insertions(+), 9 deletions(-)

diff --git a/src/device.c b/src/device.c
index 532d399..e888ac3 100644
--- a/src/device.c
+++ b/src/device.c
@@ -171,8 +171,8 @@ static netdev_tx_t wg_xmit(struct sk_buff *skb, struct net_device *dev)
 		dev_kfree_skb(skb);
 		skb = segs;
 	}
-	do {
-		next = skb->next;
+
+	skb_list_walk_safe(skb, skb, next) {
 		skb_mark_not_on_list(skb);
 
 		skb = skb_share_check(skb, GFP_ATOMIC);
@@ -187,7 +187,7 @@ static netdev_tx_t wg_xmit(struct sk_buff *skb, struct net_device *dev)
 		PACKET_CB(skb)->mtu = mtu;
 
 		__skb_queue_tail(&packets, skb);
-	} while ((skb = next) != NULL);
+	}
 
 	spin_lock_bh(&peer->staged_packet_queue.lock);
 	/* If the queue is getting too big, we start removing the oldest packets
diff --git a/src/device.h b/src/device.h
index b15a8be..c91f305 100644
--- a/src/device.h
+++ b/src/device.h
@@ -62,4 +62,12 @@ struct wg_device {
 int wg_device_init(void);
 void wg_device_uninit(void);
 
+/* Later after the dust settles, this can be moved into include/linux/skbuff.h,
+ * where virtually all code that deals with GSO segs can benefit, around ~30
+ * drivers as of writing.
+ */
+#define skb_list_walk_safe(first, skb, next)                                   \
+	for (skb = first, next = skb->next; skb;                               \
+	     skb = next, next = skb ? skb->next : NULL)
+
 #endif /* _WG_DEVICE_H */
diff --git a/src/send.c b/src/send.c
index 3da27d6..9b54f4a 100644
--- a/src/send.c
+++ b/src/send.c
@@ -233,10 +233,6 @@ void wg_packet_send_keepalive(struct wg_peer *peer)
 	wg_packet_send_staged_packets(peer);
 }
 
-#define skb_walk_null_queue_safe(first, skb, next)                             \
-	for (skb = first, next = skb->next; skb;                               \
-	     skb = next, next = skb ? skb->next : NULL)
-
 static void wg_packet_create_data_done(struct sk_buff *first,
 				       struct wg_peer *peer)
 {
@@ -245,7 +241,7 @@ static void wg_packet_create_data_done(struct sk_buff *first,
 
 	wg_timers_any_authenticated_packet_traversal(peer);
 	wg_timers_any_authenticated_packet_sent(peer);
-	skb_walk_null_queue_safe(first, skb, next) {
+	skb_list_walk_safe(first, skb, next) {
 		is_keepalive = skb->len == message_data_len(0);
 		if (likely(!wg_socket_send_skb_to_peer(peer, skb,
 				PACKET_CB(skb)->ds) && !is_keepalive))
@@ -295,7 +291,7 @@ void wg_packet_encrypt_worker(struct work_struct *work)
 	while ((first = ptr_ring_consume_bh(&queue->ring)) != NULL) {
 		enum packet_state state = PACKET_STATE_CRYPTED;
 
-		skb_walk_null_queue_safe(first, skb, next) {
+		skb_list_walk_safe(first, skb, next) {
 			if (likely(encrypt_packet(skb,
 						  PACKET_CB(first)->keypair,
 						  &simd_context))) {
-- 
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