[WAN]: kfree of NULL pointer is valid

kfree(0) is perfectly valid, checking pointers for NULL before calling 
kfree() on them is redundant. The patch below cleans away a few such 
redundant checks (and while I was around some of those bits I couldn't 
stop myself from making a few tiny whitespace changes as well).
Signed-off-by: NJesper Juhl <juhl-lkml@dif.dk>
Acked-by: NArnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/wan/cycx_x25.c

@@ -436,9 +436,7 @@ static int cycx_wan_new_if(struct wan_device *wandev, struct net_device *dev,
 	}
 
 	if (err) {
-		if (chan->local_addr)
 		kfree(chan->local_addr);
-
 		kfree(chan);
 		return err;
 	}
@@ -458,9 +456,7 @@ static int cycx_wan_del_if(struct wan_device *wandev, struct net_device *dev)
 		struct cycx_x25_channel *chan = dev->priv;
 
 		if (chan->svc) {
-			if (chan->local_addr)
 			kfree(chan->local_addr);
-
 			if (chan->state == WAN_CONNECTED)
 				del_timer(&chan->timer);
 		}

drivers/net/wan/pc300_tty.c

@@ -400,10 +400,8 @@ static void cpc_tty_close(struct tty_struct *tty, struct file *flip)
 		cpc_tty->buf_rx.last = NULL;
 	}
 	
-	if (cpc_tty->buf_tx) {
 	kfree(cpc_tty->buf_tx);
 	cpc_tty->buf_tx = NULL;
-	}
 
 	CPC_TTY_DBG("%s: TTY closed\n",cpc_tty->name);
 	
@@ -666,7 +664,7 @@ static void cpc_tty_rx_work(void * data)
 	unsigned long port;
 	int i, j;
 	st_cpc_tty_area *cpc_tty; 
-	volatile st_cpc_rx_buf * buf;
+	volatile st_cpc_rx_buf *buf;
 	char flags=0,flg_rx=1; 
 	struct tty_ldisc *ld;
 
@@ -680,9 +678,9 @@ static void cpc_tty_rx_work(void * data)
 			cpc_tty = &cpc_tty_area[port];
 		
 			if ((buf=cpc_tty->buf_rx.first) != 0) {
-				if(cpc_tty->tty) {
+				if (cpc_tty->tty) {
 					ld = tty_ldisc_ref(cpc_tty->tty);
-					if(ld) {
+					if (ld) {
 						if (ld->receive_buf) {
 							CPC_TTY_DBG("%s: call line disc. receive_buf\n",cpc_tty->name);
 							ld->receive_buf(cpc_tty->tty, (char *)(buf->data), &flags, buf->size);
@@ -691,7 +689,7 @@ static void cpc_tty_rx_work(void * data)
 					}
 				}	
 				cpc_tty->buf_rx.first = cpc_tty->buf_rx.first->next;
-				kfree((unsigned char *)buf);
+				kfree(buf);
 				buf = cpc_tty->buf_rx.first;
 				flg_rx = 1;
 			}
@@ -742,7 +740,7 @@ void cpc_tty_receive(pc300dev_t *pc300dev)
 	int rx_len, rx_aux; 
 	volatile unsigned char status; 
 	unsigned short first_bd = pc300chan->rx_first_bd;
-	st_cpc_rx_buf	*new=NULL;
+	st_cpc_rx_buf *new = NULL;
 	unsigned char dsr_rx;
 
 	if (pc300dev->cpc_tty == NULL) { 
@@ -762,7 +760,7 @@ void cpc_tty_receive(pc300dev_t *pc300dev)
 			if (status & DST_EOM) {
 				break;
 			}
-			ptdescr=(pcsca_bd_t __iomem *)(card->hw.rambase+cpc_readl(&ptdescr->next));
+			ptdescr = (pcsca_bd_t __iomem *)(card->hw.rambase+cpc_readl(&ptdescr->next));
 		}
 			
 		if (!rx_len) { 
@@ -771,10 +769,7 @@ void cpc_tty_receive(pc300dev_t *pc300dev)
 				cpc_writel(card->hw.scabase + DRX_REG(EDAL, ch), 
 						RX_BD_ADDR(ch, pc300chan->rx_last_bd)); 
 			}
-			if (new) {
 			kfree(new);
-				new = NULL;
-			}
 			return; 
 		}
 		
@@ -787,7 +782,7 @@ void cpc_tty_receive(pc300dev_t *pc300dev)
 			continue;
 		} 
 		
-		new = (st_cpc_rx_buf *) kmalloc(rx_len + sizeof(st_cpc_rx_buf), GFP_ATOMIC);
+		new = (st_cpc_rx_buf *)kmalloc(rx_len + sizeof(st_cpc_rx_buf), GFP_ATOMIC);
 		if (new == 0) {
 			cpc_tty_rx_disc_frame(pc300chan);
 			continue;

drivers/net/wan/sdla_chdlc.c

@@ -3664,15 +3664,10 @@ static void wanpipe_tty_close(struct tty_struct *tty, struct file * filp)
 		chdlc_disable_comm_shutdown(card);
 		unlock_adapter_irq(&card->wandev.lock,&smp_flags);
 
-		if (card->tty_buf){
 		kfree(card->tty_buf);
-			card->tty_buf=NULL;			
-		}
-
-		if (card->tty_rx){
+		card->tty_buf = NULL;			
 		kfree(card->tty_rx);
-			card->tty_rx=NULL;
-		}
+		card->tty_rx = NULL;
 	}
 	return;
 }

drivers/net/wan/x25_asy.c

@@ -107,13 +107,9 @@ static struct x25_asy *x25_asy_alloc(void)
 static void x25_asy_free(struct x25_asy *sl)
 {
 	/* Free all X.25 frame buffers. */
-	if (sl->rbuff)  {
 	kfree(sl->rbuff);
-	}
 	sl->rbuff = NULL;
-	if (sl->xbuff)  {
 	kfree(sl->xbuff);
-	}
 	sl->xbuff = NULL;
 
 	if (!test_and_clear_bit(SLF_INUSE, &sl->flags)) {
@@ -134,9 +130,7 @@ static int x25_asy_change_mtu(struct net_device *dev, int newmtu)
 	{
 		printk("%s: unable to grow X.25 buffers, MTU change cancelled.\n",
 		       dev->name);
-		if (xbuff != NULL)  
 		kfree(xbuff);
-		if (rbuff != NULL)  
 		kfree(rbuff);
 		return -ENOMEM;
 	}
@@ -169,9 +163,7 @@ static int x25_asy_change_mtu(struct net_device *dev, int newmtu)
 
 	spin_unlock_bh(&sl->lock);
 
-	if (xbuff != NULL) 
 	kfree(xbuff);
-	if (rbuff != NULL)
 	kfree(rbuff);
 	return 0;
 }