caif: Don't resend if dev_queue_xmit fails.

If CAIF Link Layer returns an error, we no longer try to re-build the
CAIF packet and resend it. Instead, we simply return any transmission
errors to the socket client.
Signed-off-by: Sjur Brændeland <sjur.brandeland@stericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/caif/caif_dev.c

@@ -120,25 +120,12 @@ static int transmit(struct cflayer *layer, struct cfpkt *pkt)
 {
 	struct caif_device_entry *caifd =
 	    container_of(layer, struct caif_device_entry, layer);
-	struct sk_buff *skb, *skb2;
-	int ret = -EINVAL;
+	struct sk_buff *skb;
+
 	skb = cfpkt_tonative(pkt);
 	skb->dev = caifd->netdev;
-	/*
-	 * Don't allow SKB to be destroyed upon error, but signal resend
-	 * notification to clients. We can't rely on the return value as
-	 * congestion (NET_XMIT_CN) sometimes drops the packet, sometimes don't.
-	 */
-	if (netif_queue_stopped(caifd->netdev))
-		return -EAGAIN;
-	skb2 = skb_get(skb);
-
-	ret = dev_queue_xmit(skb2);
-
-	if (!ret)
-		kfree_skb(skb);
-	else
-		return -EAGAIN;
+
+	dev_queue_xmit(skb);
 
 	return 0;
 }

net/caif/caif_socket.c

@@ -519,43 +519,14 @@ static int transmit_skb(struct sk_buff *skb, struct caifsock *cf_sk,
 			int noblock, long timeo)
 {
 	struct cfpkt *pkt;
-	int ret, loopcnt = 0;
 
 	pkt = cfpkt_fromnative(CAIF_DIR_OUT, skb);
 	memset(cfpkt_info(pkt), 0, sizeof(struct caif_payload_info));
-	do {
-
-		ret = -ETIMEDOUT;
 
-		/* Slight paranoia, probably not needed. */
-		if (unlikely(loopcnt++ > 1000)) {
-			pr_warn("transmit retries failed, error = %d\n", ret);
-			break;
-		}
+	if (cf_sk->layer.dn == NULL)
+		return -EINVAL;
 
-		if (cf_sk->layer.dn != NULL)
-			ret = cf_sk->layer.dn->transmit(cf_sk->layer.dn, pkt);
-		if (likely(ret >= 0))
-			break;
-		/* if transmit return -EAGAIN, then retry */
-		if (noblock && ret == -EAGAIN)
-			break;
-		timeo = caif_wait_for_flow_on(cf_sk, 0, timeo, &ret);
-		if (signal_pending(current)) {
-			ret = sock_intr_errno(timeo);
-			break;
-		}
-		if (ret)
-			break;
-		if (cf_sk->sk.sk_state != CAIF_CONNECTED ||
-			sock_flag(&cf_sk->sk, SOCK_DEAD) ||
-			(cf_sk->sk.sk_shutdown & RCV_SHUTDOWN)) {
-			ret = -EPIPE;
-			cf_sk->sk.sk_err = EPIPE;
-			break;
-		}
-	} while (ret == -EAGAIN);
-	return ret;
+	return cf_sk->layer.dn->transmit(cf_sk->layer.dn, pkt);
 }
 
 /* Copied from af_unix:unix_dgram_sendmsg, and adapted to CAIF */

net/caif/cfdgml.c

@@ -108,10 +108,5 @@ static int cfdgml_transmit(struct cflayer *layr, struct cfpkt *pkt)
 	 */
 	info->hdr_len = 4;
 	info->dev_info = &service->dev_info;
-	ret = layr->dn->transmit(layr->dn, pkt);
-	if (ret < 0) {
-		u32 tmp32;
-		cfpkt_extr_head(pkt, &tmp32, 4);
-	}
-	return ret;
+	return layr->dn->transmit(layr->dn, pkt);
 }

net/caif/cffrml.c

@@ -120,7 +120,6 @@ static int cffrml_transmit(struct cflayer *layr, struct cfpkt *pkt)
 	int tmp;
 	u16 chks;
 	u16 len;
-	int ret;
 	struct cffrml *this = container_obj(layr);
 	if (this->dofcs) {
 		chks = cfpkt_iterate(pkt, cffrml_checksum, 0xffff);
@@ -137,12 +136,7 @@ static int cffrml_transmit(struct cflayer *layr, struct cfpkt *pkt)
 		pr_err("Packet is erroneous!\n");
 		return -EPROTO;
 	}
-	ret = layr->dn->transmit(layr->dn, pkt);
-	if (ret < 0) {
-		/* Remove header on faulty packet. */
-		cfpkt_extr_head(pkt, &tmp, 2);
-	}
-	return ret;
+	return layr->dn->transmit(layr->dn, pkt);
 }
 
 static void cffrml_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,

net/caif/cfmuxl.c

@@ -184,7 +184,6 @@ static int cfmuxl_receive(struct cflayer *layr, struct cfpkt *pkt)
 
 static int cfmuxl_transmit(struct cflayer *layr, struct cfpkt *pkt)
 {
-	int ret;
 	struct cfmuxl *muxl = container_obj(layr);
 	u8 linkid;
 	struct cflayer *dn;
@@ -198,11 +197,7 @@ static int cfmuxl_transmit(struct cflayer *layr, struct cfpkt *pkt)
 	info->hdr_len += 1;
 	linkid = info->channel_id;
 	cfpkt_add_head(pkt, &linkid, 1);
-	ret = dn->transmit(dn, pkt);
-	/* Remove MUX protocol header upon error. */
-	if (ret < 0)
-		cfpkt_extr_head(pkt, &linkid, 1);
-	return ret;
+	return dn->transmit(dn, pkt);
 }
 
 static void cfmuxl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,

net/caif/cfserl.c

@@ -179,15 +179,10 @@ static int cfserl_receive(struct cflayer *l, struct cfpkt *newpkt)
 static int cfserl_transmit(struct cflayer *layer, struct cfpkt *newpkt)
 {
 	struct cfserl *layr = container_obj(layer);
-	int ret;
 	u8 tmp8 = CFSERL_STX;
 	if (layr->usestx)
 		cfpkt_add_head(newpkt, &tmp8, 1);
-	ret = layer->dn->transmit(layer->dn, newpkt);
-	if (ret < 0)
-		cfpkt_extr_head(newpkt, &tmp8, 1);
-
-	return ret;
+	return layer->dn->transmit(layer->dn, newpkt);
 }
 
 static void cfserl_ctrlcmd(struct cflayer *layr, enum caif_ctrlcmd ctrl,

net/caif/cfutill.c

@@ -100,10 +100,5 @@ static int cfutill_transmit(struct cflayer *layr, struct cfpkt *pkt)
 	 */
 	info->hdr_len = 1;
 	info->dev_info = &service->dev_info;
-	ret = layr->dn->transmit(layr->dn, pkt);
-	if (ret < 0) {
-		u32 tmp32;
-		cfpkt_extr_head(pkt, &tmp32, 4);
-	}
-	return ret;
+	return layr->dn->transmit(layr->dn, pkt);
 }

net/caif/cfveil.c

@@ -96,8 +96,5 @@ static int cfvei_transmit(struct cflayer *layr, struct cfpkt *pkt)
 	info->channel_id = service->layer.id;
 	info->hdr_len = 1;
 	info->dev_info = &service->dev_info;
-	ret = layr->dn->transmit(layr->dn, pkt);
-	if (ret < 0)
-		cfpkt_extr_head(pkt, &tmp, 1);
-	return ret;
+	return layr->dn->transmit(layr->dn, pkt);
 }

net/caif/cfvidl.c

@@ -60,8 +60,5 @@ static int cfvidl_transmit(struct cflayer *layr, struct cfpkt *pkt)
 	info = cfpkt_info(pkt);
 	info->channel_id = service->layer.id;
 	info->dev_info = &service->dev_info;
-	ret = layr->dn->transmit(layr->dn, pkt);
-	if (ret < 0)
-		cfpkt_extr_head(pkt, &videoheader, 4);
-	return ret;
+	return layr->dn->transmit(layr->dn, pkt);
 }