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>

9 files changed, 14 insertions, 88 deletions

diff --git a/net/caif/caif_dev.c b/net/caif/caif_dev.c
index b533bb09a002..a518fdd4da0a 100644
--- a/net/caif/caif_dev.c
+++ b/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;
 }
diff --git a/net/caif/caif_socket.c b/net/caif/caif_socket.c
index 37a4034dfc29..20212424e2e8 100644
--- a/net/caif/caif_socket.c
+++ b/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 */
diff --git a/net/caif/cfdgml.c b/net/caif/cfdgml.c
index 054fdb5aeb88..0382dec84fdc 100644
--- a/net/caif/cfdgml.c
+++ b/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);
 }
diff --git a/net/caif/cffrml.c b/net/caif/cffrml.c
index a445043931ae..2423fed8e26c 100644
--- a/net/caif/cffrml.c
+++ b/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,
diff --git a/net/caif/cfmuxl.c b/net/caif/cfmuxl.c
index f8ce0f3d9210..ebfda2c9290b 100644
--- a/net/caif/cfmuxl.c
+++ b/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,
diff --git a/net/caif/cfserl.c b/net/caif/cfserl.c
index 8303fe3ebf89..2715c84cfa87 100644
--- a/net/caif/cfserl.c
+++ b/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,
diff --git a/net/caif/cfutill.c b/net/caif/cfutill.c
index 315c0d601368..98e027db18ed 100644
--- a/net/caif/cfutill.c
+++ b/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);
 }
diff --git a/net/caif/cfveil.c b/net/caif/cfveil.c
index c3b1dec4acf6..1a588cd818ea 100644
--- a/net/caif/cfveil.c
+++ b/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);
 }
diff --git a/net/caif/cfvidl.c b/net/caif/cfvidl.c
index bf6fef2a0eff..b2f5989ad455 100644
--- a/net/caif/cfvidl.c
+++ b/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);
 }