net/core: Fix BUG to BUG_ON conditionals.

Fix BUG() calls to use BUG_ON(conditional) macros.

This was found using make coccicheck M=net/core on linux next
tag next-2017092

Signed-off-by: Tim Hansen <devtimhansen@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/core/skbuff.c

@@ -1350,8 +1350,7 @@ struct sk_buff *skb_copy(const struct sk_buff *skb, gfp_t gfp_mask)
 	/* Set the tail pointer and length */
 	skb_put(n, skb->len);
 
-	if (skb_copy_bits(skb, -headerlen, n->head, headerlen + skb->len))
-		BUG();
+	BUG_ON(skb_copy_bits(skb, -headerlen, n->head, headerlen + skb->len));
 
 	copy_skb_header(n, skb);
 	return n;
@@ -1449,8 +1448,7 @@ int pskb_expand_head(struct sk_buff *skb, int nhead, int ntail,
 
 	BUG_ON(nhead < 0);
 
-	if (skb_shared(skb))
-		BUG();
+	BUG_ON(skb_shared(skb));
 
 	size = SKB_DATA_ALIGN(size);
 
@@ -1595,9 +1593,8 @@ struct sk_buff *skb_copy_expand(const struct sk_buff *skb,
 		head_copy_off = newheadroom - head_copy_len;
 
 	/* Copy the linear header and data. */
-	if (skb_copy_bits(skb, -head_copy_len, n->head + head_copy_off,
-			  skb->len + head_copy_len))
-		BUG();
+	BUG_ON(skb_copy_bits(skb, -head_copy_len, n->head + head_copy_off,
+			     skb->len + head_copy_len));
 
 	copy_skb_header(n, skb);
 
@@ -1878,8 +1875,8 @@ void *__pskb_pull_tail(struct sk_buff *skb, int delta)
 			return NULL;
 	}
 
-	if (skb_copy_bits(skb, skb_headlen(skb), skb_tail_pointer(skb), delta))
-		BUG();
+	BUG_ON(skb_copy_bits(skb, skb_headlen(skb),
+			     skb_tail_pointer(skb), delta));
 
 	/* Optimization: no fragments, no reasons to preestimate
 	 * size of pulled pages. Superb.