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[RFC,2/4] Bluetooth: Add bt_skb_sendmmsg helper

Message ID 20210831011528.225877-2-luiz.dentz@gmail.com (mailing list archive)
State Superseded
Headers show
Series [RFC,1/4] Bluetooth: Add bt_skb_sendmsg helper | expand

Commit Message

Luiz Augusto von Dentz Aug. 31, 2021, 1:15 a.m. UTC 
From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

This works similarly to bt_skb_sendmsg but can split the msg into
multiple skb fragments which is useful for stream sockets.

Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
---
 include/net/bluetooth/bluetooth.h | 35 +++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)
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Patch

diff --git a/include/net/bluetooth/bluetooth.h b/include/net/bluetooth/bluetooth.h
index 1bfb5d3d24dd..1d66bccdf539 100644
--- a/include/net/bluetooth/bluetooth.h
+++ b/include/net/bluetooth/bluetooth.h
@@ -443,6 +443,41 @@  static inline struct sk_buff *bt_skb_sendmsg(struct sock *sk,
 	return skb;
 }
 
+/* Similar to bt_skb_sendmsg but can split the msg into multiple fragments
+ * accourding to the MTU.
+ */
+static inline struct sk_buff *bt_skb_sendmmsg(struct sock *sk,
+					      struct msghdr *msg,
+					      size_t len, size_t mtu,
+					      int reserve)
+{
+	struct sk_buff *skb, **frag;
+	size_t size = min_t(size_t, len, mtu);
+
+	skb = bt_skb_sendmsg(sk, msg, size, reserve);
+	if (IS_ERR_OR_NULL(skb))
+		return skb;
+
+	len -= size;
+	if (!len)
+		return skb;
+
+	/* Add remaining data over MTU as continuation fragments */
+	frag = &skb_shinfo(skb)->frag_list;
+	while (len) {
+		*frag = bt_skb_sendmsg(sk, msg, size, reserve);
+		if (IS_ERR_OR_NULL(*frag)) {
+			kfree_skb(skb);
+			return *frag;
+		}
+
+		len -= (*frag)->len;
+		frag = &(*frag)->next;
+	}
+
+	return skb;
+}
+
 int bt_to_errno(u16 code);
 
 void hci_sock_set_flag(struct sock *sk, int nr);