Re: [RFC 1/4] Bluetooth: Add bt_skb_sendmsg helper
From: Marcel Holtmann <marcel@holtmann.org>
Date: 2021-08-31 08:35:54
Hi Luiz,
quoted hunk ↗ jump to hunk
bt_skb_sendmsg helps takes care of allocation the skb and copying the the contents of msg over to the skb while checking for possible errors so it should be safe to call it without holding lock_sock. Signed-off-by: Luiz Augusto von Dentz <redacted> --- include/net/bluetooth/bluetooth.h | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+)diff --git a/include/net/bluetooth/bluetooth.h b/include/net/bluetooth/bluetooth.h index 9125effbf448..1bfb5d3d24dd 100644 --- a/include/net/bluetooth/bluetooth.h +++ b/include/net/bluetooth/bluetooth.h@@ -420,6 +420,29 @@ static inline struct sk_buff *bt_skb_send_alloc(struct sock *sk,return NULL; } +/* Shall not be called with lock_sock held */ +static inline struct sk_buff *bt_skb_sendmsg(struct sock *sk, + struct msghdr *msg, + size_t len, int reserve) +{ + struct sk_buff *skb; + int err; + + skb = bt_skb_send_alloc(sk, len, msg->msg_flags & MSG_DONTWAIT, &err); + if (!skb) + return ERR_PTR(err); + + if (memcpy_from_msg(skb_put(skb, len), msg, len)) { + kfree_skb(skb); + return ERR_PTR(-EFAULT); + } + + skb_reserve(skb, reserve); + skb->priority = sk->sk_priority;
have you tested this? I remember vaguely (really vaguely actually) that skb_reserve needs to be called before you do any changes to the buffer via skb_put and others. Especially since bt_skb_send_alloc already calls skb_reserve in the first place. Regards Marcel