mctp i2c: notify user space on TX failure

Currently, there is no error handling mechanism for TX failures, causing
user space to remain unaware of these failures until a timeout occurs.
This leads to unnecessary waiting and delays.

This update sends an immediate error notification to user space upon TX
failure, reducing wait times and improving response handling for failed
tx.

Signed-off-by: Jian Zhang <zhangjian.3032@bytedance.com>
Signed-off-by: NipaLocal <nipa@local>

drivers/net/mctp/mctp-i2c.c

@@ -485,6 +485,7 @@ static void mctp_i2c_xmit(struct mctp_i2c_dev *midev, struct sk_buff *skb)
 	struct mctp_i2c_hdr *hdr;
 	struct i2c_msg msg = {0};
 	u8 *pecp;
+	struct sock *sk;
 	int rc;
 
 	fs = mctp_i2c_get_tx_flow_state(midev, skb);
@@ -551,6 +552,14 @@ static void mctp_i2c_xmit(struct mctp_i2c_dev *midev, struct sk_buff *skb)
 		dev_warn_ratelimited(&midev->adapter->dev,
 				     "__i2c_transfer failed %d\n", rc);
 		stats->tx_errors++;
+
+		sk = skb->sk;
+		if (sk) {
+			sk->sk_err = -rc;
+			if (!sock_flag(sk, SOCK_DEAD))
+				sk_error_report(sk);
+		}
+
 	} else {
 		stats->tx_bytes += skb->len;
 		stats->tx_packets++;