[S390]: Fix use of skb after netif_rx

Author: Julia Lawall <julia@diku.dk>

Recently, Wang Chen submitted a patch
(d30f53aeb31d453a5230f526bea592af07944564) to move a call to netif_rx(skb)
after a subsequent reference to skb, because netif_rx may call kfree_skb on
its argument.  netif_rx_ni calls netif_rx, so the same problem occurs in
the files below.

I have left the updating of dev->last_rx after the calls to netif_rx_ni
because it seems time dependent, but moved the other field updates before.

This was found using the following semantic match.
(http://www.emn.fr/x-info/coccinelle/)

// 
@@
expression skb, e,e1;
@@

(
 netif_rx(skb);
|
 netif_rx_ni(skb);
)
  ... when != skb = e
(
  skb = e1
|
* skb
)
// 

Signed-off-by: Julia Lawall 
Signed-off-by: David S. Miller

---
 drivers/s390/net/ctcmain.c | 6 +++---
 drivers/s390/net/netiucv.c | 4 ++--
 2 files changed, 5 insertions(+), 5 deletions(-)
 
diff --git a/drivers/s390/net/ctcmain.c b/drivers/s390/net/ctcmain.c
index 97adc70..77a5031 100644
--- a/drivers/s390/net/ctcmain.c
+++ b/drivers/s390/net/ctcmain.c
@@ -478,14 +478,14 @@ ctc_unpack_skb(struct channel *ch, struct sk_buff *pskb)
 		skb->dev = pskb->dev;
 		skb->protocol = pskb->protocol;
 		pskb->ip_summed = CHECKSUM_UNNECESSARY;
-		netif_rx_ni(skb);
 		/**
-		 * Successful rx; reset logflags
+		 * reset logflags
 		 */
 		ch->logflags = 0;
-		dev->last_rx = jiffies;
 		privptr->stats.rx_packets++;
 		privptr->stats.rx_bytes += skb->len;
+		netif_rx_ni(skb);
+		dev->last_rx = jiffies;
 		if (len > 0) {
 			skb_pull(pskb, header->length);
 			if (skb_tailroom(pskb) < LL_HEADER_LENGTH) {
diff --git a/drivers/s390/net/netiucv.c b/drivers/s390/net/netiucv.c
index 4d18d64..c7ea938 100644
--- a/drivers/s390/net/netiucv.c
+++ b/drivers/s390/net/netiucv.c
@@ -639,14 +639,14 @@ static void netiucv_unpack_skb(struct iucv_connection *conn,
 		skb->dev = pskb->dev;
 		skb->protocol = pskb->protocol;
 		pskb->ip_summed = CHECKSUM_UNNECESSARY;
+		privptr->stats.rx_packets++;
+		privptr->stats.rx_bytes += skb->len;
 		/*
 		 * Since receiving is always initiated from a tasklet (in iucv.c),
 		 * we must use netif_rx_ni() instead of netif_rx()
 		 */
 		netif_rx_ni(skb);
 		dev->last_rx = jiffies;
-		privptr->stats.rx_packets++;
-		privptr->stats.rx_bytes += skb->len;
 		skb_pull(pskb, header->next);
 		skb_put(pskb, NETIUCV_HDRLEN);
 	}

[S390]: Fix use of skb after netif_rx

qlambert

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