[net-next-2.6 PATCH] ethtool: update get_rx_ntuple to correctly interpret string count

[Alexander Duyck <alexander.h.duyck@intel.com>]

Currently any strings returned via the get_rx_ntuple call will just be
dropped because the num_strings will be zero.  In order to correct this I
am updating things so that the return value of get_rx_ntuple is the number
of strings that were written, or a negative value if there was an error.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
---

 net/core/ethtool.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/net/core/ethtool.c b/net/core/ethtool.c
index 1774178..7ade13b 100644
--- a/net/core/ethtool.c
+++ b/net/core/ethtool.c
@@ -587,6 +587,9 @@ static int ethtool_get_rx_ntuple(struct net_device *dev, void __user *useraddr)
 	if (ops->get_rx_ntuple) {
 		/* driver-specific filter grab */
 		ret = ops->get_rx_ntuple(dev, gstrings.string_set, data);
+		if (ret < 0)
+			goto out;
+		num_strings = ret;
 		goto copy;
 	}