skbuff: Add skb parameter to the ubuf zerocopy callback

Add an optional skb parameter to the zerocopy callback parameter,
which is passed down from skb_zcopy_clear().  This gives access
to the original skb, which is needed for upcoming RX zero-copy
error handling.
Signed-off-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/tap.c

@@ -727,7 +727,7 @@ static ssize_t tap_get_user(struct tap_queue *q, void *msg_control,
 		skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
 	} else if (msg_control) {
 		struct ubuf_info *uarg = msg_control;
-		uarg->callback(uarg, false);
+		uarg->callback(NULL, uarg, false);
 	}
 
 	if (tap) {

drivers/net/tun.c

@@ -1819,7 +1819,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
 		skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
 	} else if (msg_control) {
 		struct ubuf_info *uarg = msg_control;
-		uarg->callback(uarg, false);
+		uarg->callback(NULL, uarg, false);
 	}
 
 	skb_reset_network_header(skb);

drivers/net/xen-netback/common.h

@@ -399,7 +399,8 @@ void xenvif_rx_queue_tail(struct xenvif_queue *queue, struct sk_buff *skb);
 void xenvif_carrier_on(struct xenvif *vif);
 
 /* Callback from stack when TX packet can be released */
-void xenvif_zerocopy_callback(struct ubuf_info *ubuf, bool zerocopy_success);
+void xenvif_zerocopy_callback(struct sk_buff *skb, struct ubuf_info *ubuf,
+			      bool zerocopy_success);
 
 /* Unmap a pending page and release it back to the guest */
 void xenvif_idx_unmap(struct xenvif_queue *queue, u16 pending_idx);

drivers/net/xen-netback/netback.c

@@ -1091,7 +1091,7 @@ static int xenvif_handle_frag_list(struct xenvif_queue *queue, struct sk_buff *s
 	uarg = skb_shinfo(skb)->destructor_arg;
 	/* increase inflight counter to offset decrement in callback */
 	atomic_inc(&queue->inflight_packets);
-	uarg->callback(uarg, true);
+	uarg->callback(NULL, uarg, true);
 	skb_shinfo(skb)->destructor_arg = NULL;
 
 	/* Fill the skb with the new (local) frags. */
@@ -1228,7 +1228,8 @@ static int xenvif_tx_submit(struct xenvif_queue *queue)
 	return work_done;
 }
 
-void xenvif_zerocopy_callback(struct ubuf_info *ubuf, bool zerocopy_success)
+void xenvif_zerocopy_callback(struct sk_buff *skb, struct ubuf_info *ubuf,
+			      bool zerocopy_success)
 {
 	unsigned long flags;
 	pending_ring_idx_t index;

drivers/vhost/net.c

@@ -381,7 +381,8 @@ static void vhost_zerocopy_signal_used(struct vhost_net *net,
 	}
 }
 
-static void vhost_zerocopy_callback(struct ubuf_info *ubuf, bool success)
+static void vhost_zerocopy_callback(struct sk_buff *skb,
+				    struct ubuf_info *ubuf, bool success)
 {
 	struct vhost_net_ubuf_ref *ubufs = ubuf->ctx;
 	struct vhost_virtqueue *vq = ubufs->vq;

include/linux/skbuff.h

@@ -461,7 +461,8 @@ enum {
  * The desc field is used to track userspace buffer index.
  */
 struct ubuf_info {
-	void (*callback)(struct ubuf_info *, bool zerocopy_success);
+	void (*callback)(struct sk_buff *, struct ubuf_info *,
+			 bool zerocopy_success);
 	union {
 		struct {
 			unsigned long desc;
@@ -493,7 +494,8 @@ struct ubuf_info *sock_zerocopy_realloc(struct sock *sk, size_t size,
 
 void sock_zerocopy_put_abort(struct ubuf_info *uarg, bool have_uref);
 
-void sock_zerocopy_callback(struct ubuf_info *uarg, bool success);
+void sock_zerocopy_callback(struct sk_buff *skb, struct ubuf_info *uarg,
+			    bool success);
 
 int skb_zerocopy_iter_dgram(struct sk_buff *skb, struct msghdr *msg, int len);
 int skb_zerocopy_iter_stream(struct sock *sk, struct sk_buff *skb,
@@ -1473,20 +1475,17 @@ static inline void *skb_zcopy_get_nouarg(struct sk_buff *skb)
 static inline void skb_zcopy_put(struct ubuf_info *uarg)
 {
 	if (uarg)
-		uarg->callback(uarg, true);
+		uarg->callback(NULL, uarg, true);
 }
 
 /* Release a reference on a zerocopy structure */
-static inline void skb_zcopy_clear(struct sk_buff *skb, bool zerocopy)
+static inline void skb_zcopy_clear(struct sk_buff *skb, bool zerocopy_success)
 {
 	struct ubuf_info *uarg = skb_zcopy(skb);
 
 	if (uarg) {
-		if (skb_zcopy_is_nouarg(skb)) {
-			/* no notification callback */
-		} else {
-			uarg->callback(uarg, zerocopy);
-		}
+		if (!skb_zcopy_is_nouarg(skb))
+			uarg->callback(skb, uarg, zerocopy_success);
 
 		skb_shinfo(skb)->tx_flags &= ~SKBTX_ZEROCOPY_FRAG;
 	}

net/core/skbuff.c

@@ -1242,7 +1242,8 @@ static void __sock_zerocopy_callback(struct ubuf_info *uarg)
 	sock_put(sk);
 }
 
-void sock_zerocopy_callback(struct ubuf_info *uarg, bool success)
+void sock_zerocopy_callback(struct sk_buff *skb, struct ubuf_info *uarg,
+			    bool success)
 {
 	uarg->zerocopy = uarg->zerocopy & success;