[PATCH] 8139cp: allocate statistics space only when needed

Don't crash if ethtool statistics are requested and device is down.
Fix is to allocate pci space for statistics only when needed.

Signed-off-by: Stephen Hemminger <[e-mail]>
Signed-off-by: Jeff Garzik <[e-mail]>

drivers/net/8139cp.c

···
 
 	struct net_device_stats net_stats;
 	struct cp_extra_stats	cp_stats;
-	struct cp_dma_stats	*nic_stats;
-	dma_addr_t		nic_stats_dma;
 
 	unsigned		rx_tail		____cacheline_aligned;
 	struct cp_desc		*rx_ring;
···
 	cp->rx_ring = mem;
 	cp->tx_ring = &cp->rx_ring[CP_RX_RING_SIZE];
 
-	mem += (CP_RING_BYTES - CP_STATS_SIZE);
-	cp->nic_stats = mem;
-	cp->nic_stats_dma = cp->ring_dma + (CP_RING_BYTES - CP_STATS_SIZE);
-
 	return cp_init_rings(cp);
 }
 
···
 	pci_free_consistent(cp->pdev, CP_RING_BYTES, cp->rx_ring, cp->ring_dma);
 	cp->rx_ring = NULL;
 	cp->tx_ring = NULL;
-	cp->nic_stats = NULL;
 }
 
 static int cp_open (struct net_device *dev)
···
 				  struct ethtool_stats *estats, u64 *tmp_stats)
 {
 	struct cp_private *cp = netdev_priv(dev);
+	struct cp_dma_stats *nic_stats;
+	dma_addr_t dma;
 	int i;
 
-	memset(cp->nic_stats, 0, sizeof(struct cp_dma_stats));
+	nic_stats = pci_alloc_consistent(cp->pdev, sizeof(*nic_stats), &dma);
+	if (!nic_stats)
+		return;
 
 	/* begin NIC statistics dump */
-	cpw32(StatsAddr + 4, (cp->nic_stats_dma >> 16) >> 16);
-	cpw32(StatsAddr, (cp->nic_stats_dma & 0xffffffff) | DumpStats);
+	cpw32(StatsAddr + 4, (u64)dma >> 32);
+	cpw32(StatsAddr, ((u64)dma & DMA_32BIT_MASK) | DumpStats);
 	cpr32(StatsAddr);
 
 	for (i = 0; i < 1000; i++) {
···
 	}
 	cpw32(StatsAddr, 0);
 	cpw32(StatsAddr + 4, 0);
+	cpr32(StatsAddr);
 
 	i = 0;
-	tmp_stats[i++] = le64_to_cpu(cp->nic_stats->tx_ok);
-	tmp_stats[i++] = le64_to_cpu(cp->nic_stats->rx_ok);
-	tmp_stats[i++] = le64_to_cpu(cp->nic_stats->tx_err);
-	tmp_stats[i++] = le32_to_cpu(cp->nic_stats->rx_err);
-	tmp_stats[i++] = le16_to_cpu(cp->nic_stats->rx_fifo);
-	tmp_stats[i++] = le16_to_cpu(cp->nic_stats->frame_align);
-	tmp_stats[i++] = le32_to_cpu(cp->nic_stats->tx_ok_1col);
-	tmp_stats[i++] = le32_to_cpu(cp->nic_stats->tx_ok_mcol);
-	tmp_stats[i++] = le64_to_cpu(cp->nic_stats->rx_ok_phys);
-	tmp_stats[i++] = le64_to_cpu(cp->nic_stats->rx_ok_bcast);
-	tmp_stats[i++] = le32_to_cpu(cp->nic_stats->rx_ok_mcast);
-	tmp_stats[i++] = le16_to_cpu(cp->nic_stats->tx_abort);
-	tmp_stats[i++] = le16_to_cpu(cp->nic_stats->tx_underrun);
+	tmp_stats[i++] = le64_to_cpu(nic_stats->tx_ok);
+	tmp_stats[i++] = le64_to_cpu(nic_stats->rx_ok);
+	tmp_stats[i++] = le64_to_cpu(nic_stats->tx_err);
+	tmp_stats[i++] = le32_to_cpu(nic_stats->rx_err);
+	tmp_stats[i++] = le16_to_cpu(nic_stats->rx_fifo);
+	tmp_stats[i++] = le16_to_cpu(nic_stats->frame_align);
+	tmp_stats[i++] = le32_to_cpu(nic_stats->tx_ok_1col);
+	tmp_stats[i++] = le32_to_cpu(nic_stats->tx_ok_mcol);
+	tmp_stats[i++] = le64_to_cpu(nic_stats->rx_ok_phys);
+	tmp_stats[i++] = le64_to_cpu(nic_stats->rx_ok_bcast);
+	tmp_stats[i++] = le32_to_cpu(nic_stats->rx_ok_mcast);
+	tmp_stats[i++] = le16_to_cpu(nic_stats->tx_abort);
+	tmp_stats[i++] = le16_to_cpu(nic_stats->tx_underrun);
 	tmp_stats[i++] = cp->cp_stats.rx_frags;
 	if (i != CP_NUM_STATS)
 		BUG();
+
+	pci_free_consistent(cp->pdev, sizeof(*nic_stats), nic_stats, dma);
 }
 
 static struct ethtool_ops cp_ethtool_ops = {