[PATCH 5.4 75/87] Bluetooth: Add bt_skb_sendmmsg helper

Greg Kroah-Hartman
2022-07-27T16:44:53Z

From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

commit 97e4e80299844bb5f6ce5a7540742ffbffae3d97 upstream.

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>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Cc: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
include/net/bluetooth/bluetooth.h | 38 ++++++++++++++++++++++++++++++++++++++
1 file changed, 38 insertions(+)

--- a/include/net/bluetooth/bluetooth.h
+++ b/include/net/bluetooth/bluetooth.h
@@ -398,6 +398,44 @@ static inline struct sk_buff *bt_skb_sen
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,
+ size_t headroom, size_t tailroom)
+{
+ struct sk_buff *skb, **frag;
+
+ skb = bt_skb_sendmsg(sk, msg, len, mtu, headroom, tailroom);
+ if (IS_ERR_OR_NULL(skb))
+ return skb;
+
+ len -= skb->len;
+ if (!len)
+ return skb;
+
+ /* Add remaining data over MTU as continuation fragments */
+ frag = &skb_shinfo(skb)->frag_list;
+ while (len) {
+ struct sk_buff *tmp;
+
+ tmp = bt_skb_sendmsg(sk, msg, len, mtu, headroom, tailroom);
+ if (IS_ERR_OR_NULL(tmp)) {
+ kfree_skb(skb);
+ return tmp;
+ }
+
+ len -= tmp->len;
+
+ *frag = tmp;
+ frag = &(*frag)->next;
+ }
+
+ return skb;
+}
+
int bt_to_errno(u16 code);

void hci_sock_set_flag(struct sock *sk, int nr);