net: extend ubuf_info callback to ops structure

We'll need to associate additional callbacks with ubuf_info, introduce
a structure holding ubuf_info callbacks. Apart from a more smarter
io_uring notification management introduced in next patches, it can be
used to generalise msg_zerocopy_put_abort() and also store
->sg_from_iter, which is currently passed in struct msghdr.

Reviewed-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://lore.kernel.org/all/a62015541de49c0e2a8a0377a1d5d0a5aeb07016.1713369317.git.asml.silence@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

5 files changed, 13 insertions, 9 deletions

diff --git a/drivers/net/tap.c b/drivers/net/tap.c
index 9f0495e8df4d..bfdd3875fe86 100644
--- a/drivers/net/tap.c
+++ b/drivers/net/tap.c
@@ -754,7 +754,7 @@ static ssize_t tap_get_user(struct tap_queue *q, void *msg_control,
 		skb_zcopy_init(skb, msg_control);
 	} else if (msg_control) {
 		struct ubuf_info *uarg = msg_control;
-		uarg->callback(NULL, uarg, false);
+		uarg->ops->complete(NULL, uarg, false);
 	}
 
 	dev_queue_xmit(skb);
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 0b3f21cba552..b7401d990680 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -1906,7 +1906,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
 		skb_zcopy_init(skb, msg_control);
 	} else if (msg_control) {
 		struct ubuf_info *uarg = msg_control;
-		uarg->callback(NULL, uarg, false);
+		uarg->ops->complete(NULL, uarg, false);
 	}
 
 	skb_reset_network_header(skb);
diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h
index 1fcbd83f7ff2..17421da139f2 100644
--- a/drivers/net/xen-netback/common.h
+++ b/drivers/net/xen-netback/common.h
@@ -390,9 +390,8 @@ bool 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 sk_buff *skb, struct ubuf_info *ubuf,
-			      bool zerocopy_success);
+/* Callbacks from stack when TX packet can be released */
+extern const struct ubuf_info_ops xenvif_ubuf_ops;
 
 static inline pending_ring_idx_t nr_pending_reqs(struct xenvif_queue *queue)
 {
diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c
index 7cff90aa8d24..65db5f14465f 100644
--- a/drivers/net/xen-netback/interface.c
+++ b/drivers/net/xen-netback/interface.c
@@ -593,7 +593,7 @@ int xenvif_init_queue(struct xenvif_queue *queue)
 
 	for (i = 0; i < MAX_PENDING_REQS; i++) {
 		queue->pending_tx_info[i].callback_struct = (struct ubuf_info_msgzc)
-			{ { .callback = xenvif_zerocopy_callback },
+			{ { .ops = &xenvif_ubuf_ops },
 			  { { .ctx = NULL,
 			      .desc = i } } };
 		queue->grant_tx_handle[i] = NETBACK_INVALID_HANDLE;
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index ef76850d9bcd..bab7e43ea05b 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -1156,7 +1156,7 @@ 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(NULL, uarg, true);
+	uarg->ops->complete(NULL, uarg, true);
 	skb_shinfo(skb)->destructor_arg = NULL;
 
 	/* Fill the skb with the new (local) frags. */
@@ -1278,8 +1278,9 @@ static int xenvif_tx_submit(struct xenvif_queue *queue)
 	return work_done;
 }
 
-void xenvif_zerocopy_callback(struct sk_buff *skb, struct ubuf_info *ubuf_base,
-			      bool zerocopy_success)
+static void xenvif_zerocopy_callback(struct sk_buff *skb,
+				     struct ubuf_info *ubuf_base,
+				     bool zerocopy_success)
 {
 	unsigned long flags;
 	pending_ring_idx_t index;
@@ -1312,6 +1313,10 @@ void xenvif_zerocopy_callback(struct sk_buff *skb, struct ubuf_info *ubuf_base,
 	xenvif_skb_zerocopy_complete(queue);
 }
 
+const struct ubuf_info_ops xenvif_ubuf_ops = {
+	.complete = xenvif_zerocopy_callback,
+};
+
 static inline void xenvif_tx_dealloc_action(struct xenvif_queue *queue)
 {
 	struct gnttab_unmap_grant_ref *gop;