ethtool: Add generic options for tunables

This patch adds new ethtool cmd, ETHTOOL_GTUNABLE & ETHTOOL_STUNABLE for getting
tunable values from driver.

Add get_tunable and set_tunable to ethtool_ops. Driver implements these
functions for getting/setting tunable value.

Signed-off-by: Govindarajulu Varadarajan <_govind@gmx.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 113 insertions, 0 deletions

diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h
index e658229fee39..c1a2d60dfb82 100644
--- a/include/linux/ethtool.h
+++ b/include/linux/ethtool.h
@@ -257,6 +257,10 @@ struct ethtool_ops {
                                      struct ethtool_eeprom *, u8 *);
         int     (*get_eee)(struct net_device *, struct ethtool_eee *);
         int     (*set_eee)(struct net_device *, struct ethtool_eee *);
+        int     (*get_tunable)(struct net_device *,
+                               const struct ethtool_tunable *, void *);
+        int     (*set_tunable)(struct net_device *,
+                               const struct ethtool_tunable *, const void *);
 
 
 };
diff --git a/include/uapi/linux/ethtool.h b/include/uapi/linux/ethtool.h
index e3c7a719c76b..7a364f2f3d3f 100644
--- a/include/uapi/linux/ethtool.h
+++ b/include/uapi/linux/ethtool.h
@@ -209,6 +209,32 @@ struct ethtool_value {
         __u32   data;
 };
 
+enum tunable_id {
+        ETHTOOL_ID_UNSPEC,
+        ETHTOOL_RX_COPYBREAK,
+};
+
+enum tunable_type_id {
+        ETHTOOL_TUNABLE_UNSPEC,
+        ETHTOOL_TUNABLE_U8,
+        ETHTOOL_TUNABLE_U16,
+        ETHTOOL_TUNABLE_U32,
+        ETHTOOL_TUNABLE_U64,
+        ETHTOOL_TUNABLE_STRING,
+        ETHTOOL_TUNABLE_S8,
+        ETHTOOL_TUNABLE_S16,
+        ETHTOOL_TUNABLE_S32,
+        ETHTOOL_TUNABLE_S64,
+};
+
+struct ethtool_tunable {
+        __u32   cmd;
+        __u32   id;
+        __u32   type_id;
+        __u32   len;
+        void    *data[0];
+};
+
 /**
  * struct ethtool_regs - hardware register dump
  * @cmd: Command number = %ETHTOOL_GREGS
@@ -1152,6 +1178,8 @@ enum ethtool_sfeatures_retval_bits {
 
 #define ETHTOOL_GRSSH           0x00000046 /* Get RX flow hash configuration */
 #define ETHTOOL_SRSSH           0x00000047 /* Set RX flow hash configuration */
+#define ETHTOOL_GTUNABLE        0x00000048 /* Get tunable configuration */
+#define ETHTOOL_STUNABLE        0x00000049 /* Set tunable configuration */
 
 /* compatibility with older code */
 #define SPARC_ETH_GSET          ETHTOOL_GSET
diff --git a/net/core/ethtool.c b/net/core/ethtool.c
index 17cb912793fa..27e61b886520 100644
--- a/net/core/ethtool.c
+++ b/net/core/ethtool.c
@@ -1621,6 +1621,80 @@ static int ethtool_get_module_eeprom(struct net_device *dev,
                                       modinfo.eeprom_len);
 }
 
+static int ethtool_tunable_valid(const struct ethtool_tunable *tuna)
+{
+        switch (tuna->id) {
+        case ETHTOOL_RX_COPYBREAK:
+                if (tuna->len != sizeof(u32) ||
+                    tuna->type_id != ETHTOOL_TUNABLE_U32)
+                        return -EINVAL;
+                break;
+        default:
+                return -EINVAL;
+        }
+
+        return 0;
+}
+
+static int ethtool_get_tunable(struct net_device *dev, void __user *useraddr)
+{
+        int ret;
+        struct ethtool_tunable tuna;
+        const struct ethtool_ops *ops = dev->ethtool_ops;
+        void *data;
+
+        if (!ops->get_tunable)
+                return -EOPNOTSUPP;
+        if (copy_from_user(&tuna, useraddr, sizeof(tuna)))
+                return -EFAULT;
+        ret = ethtool_tunable_valid(&tuna);
+        if (ret)
+                return ret;
+        data = kmalloc(tuna.len, GFP_USER);
+        if (!data)
+                return -ENOMEM;
+        ret = ops->get_tunable(dev, &tuna, data);
+        if (ret)
+                goto out;
+        useraddr += sizeof(tuna);
+        ret = -EFAULT;
+        if (copy_to_user(useraddr, data, tuna.len))
+                goto out;
+        ret = 0;
+
+out:
+        kfree(data);
+        return ret;
+}
+
+static int ethtool_set_tunable(struct net_device *dev, void __user *useraddr)
+{
+        int ret;
+        struct ethtool_tunable tuna;
+        const struct ethtool_ops *ops = dev->ethtool_ops;
+        void *data;
+
+        if (!ops->set_tunable)
+                return -EOPNOTSUPP;
+        if (copy_from_user(&tuna, useraddr, sizeof(tuna)))
+                return -EFAULT;
+        ret = ethtool_tunable_valid(&tuna);
+        if (ret)
+                return ret;
+        data = kmalloc(tuna.len, GFP_USER);
+        if (!data)
+                return -ENOMEM;
+        useraddr += sizeof(tuna);
+        ret = -EFAULT;
+        if (copy_from_user(data, useraddr, tuna.len))
+                goto out;
+        ret = ops->set_tunable(dev, &tuna, data);
+
+out:
+        kfree(data);
+        return ret;
+}
+
 /* The main entry point in this file.  Called from net/core/dev_ioctl.c */
 
 int dev_ethtool(struct net *net, struct ifreq *ifr)
@@ -1670,6 +1744,7 @@ int dev_ethtool(struct net *net, struct ifreq *ifr)
         case ETHTOOL_GCHANNELS:
         case ETHTOOL_GET_TS_INFO:
         case ETHTOOL_GEEE:
+        case ETHTOOL_GTUNABLE:
                 break;
         default:
                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
@@ -1857,6 +1932,12 @@ int dev_ethtool(struct net *net, struct ifreq *ifr)
         case ETHTOOL_GMODULEEEPROM:
                 rc = ethtool_get_module_eeprom(dev, useraddr);
                 break;
+        case ETHTOOL_GTUNABLE:
+                rc = ethtool_get_tunable(dev, useraddr);
+                break;
+        case ETHTOOL_STUNABLE:
+                rc = ethtool_set_tunable(dev, useraddr);
+                break;
         default:
                 rc = -EOPNOTSUPP;
         }