net/ethtool: support set coalesce per queue

This patch implements sub command ETHTOOL_SCOALESCE for ioctl
ETHTOOL_PERQUEUE. It introduces an interface set_per_queue_coalesce to
set coalesce of each masked queue to device driver. The wanted coalesce
information are stored in "data" for each masked queue, which can copy
from userspace.
If it fails to set coalesce to device driver, the value which already
set to specific queue will be tried to rollback.

Signed-off-by: Kan Liang <kan.liang@intel.com>
Reviewed-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 61 insertions, 0 deletions

diff --git a/net/core/ethtool.c b/net/core/ethtool.c
index 2a6c3a26f63f..2406101002b1 100644
--- a/net/core/ethtool.c
+++ b/net/core/ethtool.c
@@ -1920,6 +1920,65 @@ static int ethtool_get_per_queue_coalesce(struct net_device *dev,
 	return 0;
 }
 
+static int ethtool_set_per_queue_coalesce(struct net_device *dev,
+					  void __user *useraddr,
+					  struct ethtool_per_queue_op *per_queue_opt)
+{
+	u32 bit;
+	int i, ret = 0;
+	int n_queue;
+	struct ethtool_coalesce *backup = NULL, *tmp = NULL;
+	DECLARE_BITMAP(queue_mask, MAX_NUM_QUEUE);
+
+	if ((!dev->ethtool_ops->set_per_queue_coalesce) ||
+	    (!dev->ethtool_ops->get_per_queue_coalesce))
+		return -EOPNOTSUPP;
+
+	useraddr += sizeof(*per_queue_opt);
+
+	bitmap_from_u32array(queue_mask,
+			     MAX_NUM_QUEUE,
+			     per_queue_opt->queue_mask,
+			     DIV_ROUND_UP(MAX_NUM_QUEUE, 32));
+	n_queue = bitmap_weight(queue_mask, MAX_NUM_QUEUE);
+	tmp = backup = kmalloc_array(n_queue, sizeof(*backup), GFP_KERNEL);
+	if (!backup)
+		return -ENOMEM;
+
+	for_each_set_bit(bit, queue_mask, MAX_NUM_QUEUE) {
+		struct ethtool_coalesce coalesce;
+
+		ret = dev->ethtool_ops->get_per_queue_coalesce(dev, bit, tmp);
+		if (ret != 0)
+			goto roll_back;
+
+		tmp++;
+
+		if (copy_from_user(&coalesce, useraddr, sizeof(coalesce))) {
+			ret = -EFAULT;
+			goto roll_back;
+		}
+
+		ret = dev->ethtool_ops->set_per_queue_coalesce(dev, bit, &coalesce);
+		if (ret != 0)
+			goto roll_back;
+
+		useraddr += sizeof(coalesce);
+	}
+
+roll_back:
+	if (ret != 0) {
+		tmp = backup;
+		for_each_set_bit(i, queue_mask, bit) {
+			dev->ethtool_ops->set_per_queue_coalesce(dev, i, tmp);
+			tmp++;
+		}
+	}
+	kfree(backup);
+
+	return ret;
+}
+
 static int ethtool_set_per_queue(struct net_device *dev, void __user *useraddr)
 {
 	struct ethtool_per_queue_op per_queue_opt;
@@ -1930,6 +1989,8 @@ static int ethtool_set_per_queue(struct net_device *dev, void __user *useraddr)
 	switch (per_queue_opt.sub_command) {
 	case ETHTOOL_GCOALESCE:
 		return ethtool_get_per_queue_coalesce(dev, useraddr, &per_queue_opt);
+	case ETHTOOL_SCOALESCE:
+		return ethtool_set_per_queue_coalesce(dev, useraddr, &per_queue_opt);
 	default:
 		return -EOPNOTSUPP;
 	};