[PATCH net-next v3 12/15] ibmveth: Expose per-queue buffer pool details via sysfs

[Mingming Cao <mmc@linux.ibm.com>]

Add a read-only buffer_pools sysfs attribute under the VIO device that
lists size, buff_size, active, and available for every RX queue and
pool: runtime per-queue buffer pressure during MQ operation. ethtool -S
pool%d_* (previous patch) reports queue-0 static probe geometry only;
sysfs is the right place for dynamic per-queue pool state at scale.

Signed-off-by: Mingming Cao <mmc@linux.ibm.com>
Reviewed-by: Dave Marquardt <davemarq@linux.ibm.com>
---
 drivers/net/ethernet/ibm/ibmveth.c | 56 ++++++++++++++++++++++++++++++
 1 file changed, 56 insertions(+)

diff --git a/drivers/net/ethernet/ibm/ibmveth.c b/drivers/net/ethernet/ibm/ibmveth.c
index 4e3f49b6346f..ecc472ee8f71 100644
--- a/drivers/net/ethernet/ibm/ibmveth.c
+++ b/drivers/net/ethernet/ibm/ibmveth.c
@@ -2896,6 +2896,52 @@ static const struct net_device_ops ibmveth_netdev_ops = {
 #endif
 };
 
+static const struct attribute_group ibmveth_attr_group;
+
+static ssize_t buffer_pools_show(struct device *dev,
+				 struct device_attribute *attr,
+				 char *buf)
+{
+	struct net_device *netdev = dev_get_drvdata(dev);
+	struct ibmveth_adapter *adapter = netdev_priv(netdev);
+	int len = 0;
+	int i, j;
+
+	len += scnprintf(buf + len, PAGE_SIZE - len,
+			 "Queue  Pool  Size  BuffSize  Active  Available\n");
+	len += scnprintf(buf + len, PAGE_SIZE - len,
+			 "-----  ----  ----  --------  ------  ---------\n");
+
+	for (i = 0; i < adapter->num_rx_queues; i++) {
+		for (j = 0; j < IBMVETH_NUM_BUFF_POOLS; j++) {
+			struct ibmveth_buff_pool *pool =
+				&adapter->rx_buff_pool[i][j];
+
+			len += scnprintf(buf + len, PAGE_SIZE - len,
+					 "%5d  %4d  %4u  %8u  %6d  %9d\n",
+					 i, j, pool->size, pool->buff_size,
+					 pool->active,
+					 atomic_read(&pool->available));
+
+			if (len >= PAGE_SIZE - 100)
+				goto out;
+		}
+	}
+
+out:
+	return len;
+}
+static DEVICE_ATTR_RO(buffer_pools);
+
+static struct attribute *ibmveth_attrs[] = {
+	&dev_attr_buffer_pools.attr,
+	NULL,
+};
+
+static const struct attribute_group ibmveth_attr_group = {
+	.attrs = ibmveth_attrs,
+};
+
 static int ibmveth_probe(struct vio_dev *dev, const struct vio_device_id *id)
 {
 	int rc, i, mac_len;
@@ -3056,6 +3102,14 @@ static int ibmveth_probe(struct vio_dev *dev, const struct vio_device_id *id)
 
 	netdev_dbg(netdev, "registered\n");
 
+	rc = sysfs_create_group(&dev->dev.kobj, &ibmveth_attr_group);
+	if (rc) {
+		netdev_err(netdev, "failed to create sysfs attributes rc=%d\n", rc);
+		unregister_netdev(netdev);
+		free_netdev(netdev);
+		return rc;
+	}
+
 	return 0;
 }
 
@@ -3067,6 +3121,8 @@ static void ibmveth_remove(struct vio_dev *dev)
 
 	cancel_work_sync(&adapter->work);
 
+	sysfs_remove_group(&dev->dev.kobj, &ibmveth_attr_group);
+
 	for (i = 0; i < IBMVETH_NUM_BUFF_POOLS; i++)
 		kobject_put(&adapter->rx_buff_pool[0][i].kobj);
 
-- 
2.39.3 (Apple Git-146)