ethtool: Add direct access to ops->get_sset_count

This patch is an alternative approach for accessing string
counts, vs. the drvinfo indirect approach.  This way the drvinfo
space doesn't run out, and we don't break ABI later.

Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Signed-off-by: Peter P Waskiewicz Jr <peter.p.waskiewicz.jr@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 86 insertions, 3 deletions

diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h
index cca1c3de140d..f6f961fefbe5 100644
--- a/include/linux/ethtool.h
+++ b/include/linux/ethtool.h
@@ -253,6 +253,17 @@ struct ethtool_gstrings {
         __u8    data[0];
 };
 
+struct ethtool_sset_info {
+        __u32   cmd;            /* ETHTOOL_GSSET_INFO */
+        __u32   reserved;
+        __u64   sset_mask;      /* input: each bit selects an sset to query */
+                                /* output: each bit a returned sset */
+        __u32   data[0];        /* ETH_SS_xxx count, in order, based on bits
+                                   in sset_mask.  One bit implies one
+                                   __u32, two bits implies two
+                                   __u32's, etc. */
+};
+
 enum ethtool_test_flags {
         ETH_TEST_FL_OFFLINE     = (1 << 0),     /* online / offline */
         ETH_TEST_FL_FAILED      = (1 << 1),     /* test passed / failed */
@@ -606,9 +617,9 @@ struct ethtool_ops {
 #define ETHTOOL_SRXCLSRLINS     0x00000032 /* Insert RX classification rule */
 #define ETHTOOL_FLASHDEV        0x00000033 /* Flash firmware to device */
 #define ETHTOOL_RESET           0x00000034 /* Reset hardware */
-
-#define ETHTOOL_SRXNTUPLE       0x00000035 /* Add an n-tuple filter to device */
-#define ETHTOOL_GRXNTUPLE       0x00000036 /* Get n-tuple filters from device */
+#define ETHTOOL_SRXNTUPLE       0x00000035 /* Add an n-tuple filter to device */
+#define ETHTOOL_GRXNTUPLE       0x00000036 /* Get n-tuple filters from device */
+#define ETHTOOL_GSSET_INFO      0x00000037 /* Get string set info */
 
 /* compatibility with older code */
 #define SPARC_ETH_GSET          ETHTOOL_GSET
diff --git a/net/core/ethtool.c b/net/core/ethtool.c
index 0f2f82185ec4..70075c47ada8 100644
--- a/net/core/ethtool.c
+++ b/net/core/ethtool.c
@@ -214,6 +214,10 @@ static noinline int ethtool_get_drvinfo(struct net_device *dev, void __user *use
         info.cmd = ETHTOOL_GDRVINFO;
         ops->get_drvinfo(dev, &info);
 
+        /*
+         * this method of obtaining string set info is deprecated;
+         * consider using ETHTOOL_GSSET_INFO instead
+         */
         if (ops->get_sset_count) {
                 int rc;
 
@@ -240,6 +244,71 @@ static noinline int ethtool_get_drvinfo(struct net_device *dev, void __user *use
 /*
  * noinline attribute so that gcc doesnt use too much stack in dev_ethtool()
  */
+static noinline int ethtool_get_sset_info(struct net_device *dev,
+                                          void __user *useraddr)
+{
+        struct ethtool_sset_info info;
+        const struct ethtool_ops *ops = dev->ethtool_ops;
+        u64 sset_mask;
+        int i, idx = 0, n_bits = 0, ret, rc;
+        u32 *info_buf = NULL;
+
+        if (!ops->get_sset_count)
+                return -EOPNOTSUPP;
+
+        if (copy_from_user(&info, useraddr, sizeof(info)))
+                return -EFAULT;
+
+        /* store copy of mask, because we zero struct later on */
+        sset_mask = info.sset_mask;
+        if (!sset_mask)
+                return 0;
+
+        /* calculate size of return buffer */
+        for (i = 0; i < 64; i++)
+                if (sset_mask & (1ULL << i))
+                        n_bits++;
+
+        memset(&info, 0, sizeof(info));
+        info.cmd = ETHTOOL_GSSET_INFO;
+
+        info_buf = kzalloc(n_bits * sizeof(u32), GFP_USER);
+        if (!info_buf)
+                return -ENOMEM;
+
+        /*
+         * fill return buffer based on input bitmask and successful
+         * get_sset_count return
+         */
+        for (i = 0; i < 64; i++) {
+                if (!(sset_mask & (1ULL << i)))
+                        continue;
+
+                rc = ops->get_sset_count(dev, i);
+                if (rc >= 0) {
+                        info.sset_mask |= (1ULL << i);
+                        info_buf[idx++] = rc;
+                }
+        }
+
+        ret = -EFAULT;
+        if (copy_to_user(useraddr, &info, sizeof(info)))
+                goto out;
+
+        useraddr += offsetof(struct ethtool_sset_info, data);
+        if (copy_to_user(useraddr, info_buf, idx * sizeof(u32)))
+                goto out;
+
+        ret = 0;
+
+out:
+        kfree(info_buf);
+        return ret;
+}
+
+/*
+ * noinline attribute so that gcc doesnt use too much stack in dev_ethtool()
+ */
 static noinline int ethtool_set_rxnfc(struct net_device *dev, void __user *useraddr)
 {
         struct ethtool_rxnfc cmd;
@@ -1471,6 +1540,9 @@ int dev_ethtool(struct net *net, struct ifreq *ifr)
         case ETHTOOL_GRXNTUPLE:
                 rc = ethtool_get_rx_ntuple(dev, useraddr);
                 break;
+        case ETHTOOL_GSSET_INFO:
+                rc = ethtool_get_sset_info(dev, useraddr);
+                break;
         default:
                 rc = -EOPNOTSUPP;
         }