7 files changed, 42 insertions, 23 deletions

diff --git a/drivers/net/can/at91_can.c b/drivers/net/can/at91_can.c
index f67ae285a35a..b13fd9114130 100644
--- a/drivers/net/can/at91_can.c
+++ b/drivers/net/can/at91_can.c
@@ -1087,7 +1087,7 @@ static int __init at91_can_probe(struct platform_device *pdev)
                 goto exit_release;
         }
 
-        dev = alloc_candev(sizeof(struct at91_priv));
+        dev = alloc_candev(sizeof(struct at91_priv), AT91_MB_TX_NUM);
         if (!dev) {
                 err = -ENOMEM;
                 goto exit_iounmap;
diff --git a/drivers/net/can/dev.c b/drivers/net/can/dev.c
index f0b9a1e1db46..39b99f57c265 100644
--- a/drivers/net/can/dev.c
+++ b/drivers/net/can/dev.c
@@ -245,7 +245,7 @@ static void can_flush_echo_skb(struct net_device *dev)
         struct net_device_stats *stats = &dev->stats;
         int i;
 
-        for (i = 0; i < CAN_ECHO_SKB_MAX; i++) {
+        for (i = 0; i < priv->echo_skb_max; i++) {
                 if (priv->echo_skb[i]) {
                         kfree_skb(priv->echo_skb[i]);
                         priv->echo_skb[i] = NULL;
@@ -262,10 +262,13 @@ static void can_flush_echo_skb(struct net_device *dev)
  * of the device driver. The driver must protect access to
  * priv->echo_skb, if necessary.
  */
-void can_put_echo_skb(struct sk_buff *skb, struct net_device *dev, int idx)
+void can_put_echo_skb(struct sk_buff *skb, struct net_device *dev,
+                      unsigned int idx)
 {
         struct can_priv *priv = netdev_priv(dev);
 
+        BUG_ON(idx >= priv->echo_skb_max);
+
         /* check flag whether this packet has to be looped back */
         if (!(dev->flags & IFF_ECHO) || skb->pkt_type != PACKET_LOOPBACK) {
                 kfree_skb(skb);
@@ -311,10 +314,12 @@ EXPORT_SYMBOL_GPL(can_put_echo_skb);
  * is handled in the device driver. The driver must protect
  * access to priv->echo_skb, if necessary.
  */
-void can_get_echo_skb(struct net_device *dev, int idx)
+void can_get_echo_skb(struct net_device *dev, unsigned int idx)
 {
         struct can_priv *priv = netdev_priv(dev);
 
+        BUG_ON(idx >= priv->echo_skb_max);
+
         if (priv->echo_skb[idx]) {
                 netif_rx(priv->echo_skb[idx]);
                 priv->echo_skb[idx] = NULL;
@@ -327,10 +332,12 @@ EXPORT_SYMBOL_GPL(can_get_echo_skb);
   *
   * The function is typically called when TX failed.
   */
-void can_free_echo_skb(struct net_device *dev, int idx)
+void can_free_echo_skb(struct net_device *dev, unsigned int idx)
 {
         struct can_priv *priv = netdev_priv(dev);
 
+        BUG_ON(idx >= priv->echo_skb_max);
+
         if (priv->echo_skb[idx]) {
                 kfree_skb(priv->echo_skb[idx]);
                 priv->echo_skb[idx] = NULL;
@@ -445,17 +452,30 @@ static void can_setup(struct net_device *dev)
 /*
  * Allocate and setup space for the CAN network device
  */
-struct net_device *alloc_candev(int sizeof_priv)
+struct net_device *alloc_candev(int sizeof_priv, unsigned int echo_skb_max)
 {
         struct net_device *dev;
         struct can_priv *priv;
+        int size;
 
-        dev = alloc_netdev(sizeof_priv, "can%d", can_setup);
+        if (echo_skb_max)
+                size = ALIGN(sizeof_priv, sizeof(struct sk_buff *)) +
+                        echo_skb_max * sizeof(struct sk_buff *);
+        else
+                size = sizeof_priv;
+
+        dev = alloc_netdev(size, "can%d", can_setup);
         if (!dev)
                 return NULL;
 
         priv = netdev_priv(dev);
 
+        if (echo_skb_max) {
+                priv->echo_skb_max = echo_skb_max;
+                priv->echo_skb = (void *)priv +
+                        ALIGN(sizeof_priv, sizeof(struct sk_buff *));
+        }
+
         priv->state = CAN_STATE_STOPPED;
 
         init_timer(&priv->restart_timer);
diff --git a/drivers/net/can/sja1000/sja1000.c b/drivers/net/can/sja1000/sja1000.c
index 16d2ecd2a3b7..96d8be4253f8 100644
--- a/drivers/net/can/sja1000/sja1000.c
+++ b/drivers/net/can/sja1000/sja1000.c
@@ -565,7 +565,8 @@ struct net_device *alloc_sja1000dev(int sizeof_priv)
         struct net_device *dev;
         struct sja1000_priv *priv;
 
-        dev = alloc_candev(sizeof(struct sja1000_priv) + sizeof_priv);
+        dev = alloc_candev(sizeof(struct sja1000_priv) + sizeof_priv,
+                SJA1000_ECHO_SKB_MAX);
         if (!dev)
                 return NULL;
 
diff --git a/drivers/net/can/sja1000/sja1000.h b/drivers/net/can/sja1000/sja1000.h
index 302d2c763ad7..97a622b9302f 100644
--- a/drivers/net/can/sja1000/sja1000.h
+++ b/drivers/net/can/sja1000/sja1000.h
@@ -50,6 +50,8 @@
 #include <linux/can/dev.h>
 #include <linux/can/platform/sja1000.h>
 
+#define SJA1000_ECHO_SKB_MAX    1 /* the SJA1000 has one TX buffer object */
+
 #define SJA1000_MAX_IRQ 20      /* max. number of interrupts handled in ISR */
 
 /* SJA1000 registers - manual section 6.4 (Pelican Mode) */
diff --git a/drivers/net/can/ti_hecc.c b/drivers/net/can/ti_hecc.c
index 814e6c5c6386..23a7128e4eb7 100644
--- a/drivers/net/can/ti_hecc.c
+++ b/drivers/net/can/ti_hecc.c
@@ -74,10 +74,6 @@ MODULE_VERSION(HECC_MODULE_VERSION);
 #define HECC_MB_TX_SHIFT        2 /* as per table above */
 #define HECC_MAX_TX_MBOX        BIT(HECC_MB_TX_SHIFT)
 
-#if (HECC_MAX_TX_MBOX > CAN_ECHO_SKB_MAX)
-#error "HECC: MAX TX mailboxes should be equal or less than CAN_ECHO_SKB_MAX"
-#endif
-
 #define HECC_TX_PRIO_SHIFT      (HECC_MB_TX_SHIFT)
 #define HECC_TX_PRIO_MASK       (MAX_TX_PRIO << HECC_MB_TX_SHIFT)
 #define HECC_TX_MB_MASK         (HECC_MAX_TX_MBOX - 1)
@@ -902,7 +898,7 @@ static int ti_hecc_probe(struct platform_device *pdev)
                 goto probe_exit_free_region;
         }
 
-        ndev = alloc_candev(sizeof(struct ti_hecc_priv));
+        ndev = alloc_candev(sizeof(struct ti_hecc_priv), HECC_MAX_TX_MBOX);
         if (!ndev) {
                 dev_err(&pdev->dev, "alloc_candev failed\n");
                 err = -ENOMEM;
diff --git a/drivers/net/can/usb/ems_usb.c b/drivers/net/can/usb/ems_usb.c
index 9012e0abc626..a65f56a9cd3d 100644
--- a/drivers/net/can/usb/ems_usb.c
+++ b/drivers/net/can/usb/ems_usb.c
@@ -232,7 +232,7 @@ MODULE_DEVICE_TABLE(usb, ems_usb_table);
 #define INTR_IN_BUFFER_SIZE 4
 
 #define MAX_RX_URBS 10
-#define MAX_TX_URBS CAN_ECHO_SKB_MAX
+#define MAX_TX_URBS 10
 
 struct ems_usb;
 
@@ -1012,7 +1012,7 @@ static int ems_usb_probe(struct usb_interface *intf,
         struct ems_usb *dev;
         int i, err = -ENOMEM;
 
-        netdev = alloc_candev(sizeof(struct ems_usb));
+        netdev = alloc_candev(sizeof(struct ems_usb), MAX_TX_URBS);
         if (!netdev) {
                 dev_err(netdev->dev.parent, "Couldn't alloc candev\n");
                 return -ENOMEM;
diff --git a/include/linux/can/dev.h b/include/linux/can/dev.h
index 5824b20b5fcb..1d3f7f00e3af 100644
--- a/include/linux/can/dev.h
+++ b/include/linux/can/dev.h
@@ -29,8 +29,6 @@ enum can_mode {
 /*
  * CAN common private data
  */
-#define CAN_ECHO_SKB_MAX  4
-
 struct can_priv {
         struct can_device_stats can_stats;
 
@@ -44,15 +42,16 @@ struct can_priv {
         int restart_ms;
         struct timer_list restart_timer;
 
-        struct sk_buff *echo_skb[CAN_ECHO_SKB_MAX];
-
         int (*do_set_bittiming)(struct net_device *dev);
         int (*do_set_mode)(struct net_device *dev, enum can_mode mode);
         int (*do_get_state)(const struct net_device *dev,
                             enum can_state *state);
+
+        unsigned int echo_skb_max;
+        struct sk_buff **echo_skb;
 };
 
-struct net_device *alloc_candev(int sizeof_priv);
+struct net_device *alloc_candev(int sizeof_priv, unsigned int echo_skb_max);
 void free_candev(struct net_device *dev);
 
 int open_candev(struct net_device *dev);
@@ -64,8 +63,9 @@ void unregister_candev(struct net_device *dev);
 int can_restart_now(struct net_device *dev);
 void can_bus_off(struct net_device *dev);
 
-void can_put_echo_skb(struct sk_buff *skb, struct net_device *dev, int idx);
-void can_get_echo_skb(struct net_device *dev, int idx);
-void can_free_echo_skb(struct net_device *dev, int idx);
+void can_put_echo_skb(struct sk_buff *skb, struct net_device *dev,
+                      unsigned int idx);
+void can_get_echo_skb(struct net_device *dev, unsigned int idx);
+void can_free_echo_skb(struct net_device *dev, unsigned int idx);
 
 #endif /* CAN_DEV_H */