IB/mlx5: Add delay drop configuration and statistics

Add debugfs interface for monitor the number of delay drop timeout
events and the number of existing dropless RQs in the system.

In addition add debugfs interface for configuring the global timeout value
which is used in the SET_DELAY_DROP command.

Signed-off-by: Maor Gottlieb <maorg@mellanox.com>
Reviewed-by: Yishai Hadas <yishaih@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>

1 files changed, 103 insertions, 0 deletions

diff --git a/drivers/infiniband/hw/mlx5/main.c b/drivers/infiniband/hw/mlx5/main.c
index ad4b12decc23..7455f95bf679 100644
--- a/drivers/infiniband/hw/mlx5/main.c
+++ b/drivers/infiniband/hw/mlx5/main.c
@@ -30,6 +30,7 @@
  * SOFTWARE.
  */
 
+#include <linux/debugfs.h>
 #include <linux/highmem.h>
 #include <linux/module.h>
 #include <linux/init.h>
@@ -2763,6 +2764,8 @@ static void delay_drop_handler(struct work_struct *work)
 		container_of(work, struct mlx5_ib_delay_drop,
 			     delay_drop_work);
 
+	atomic_inc(&delay_drop->events_cnt);
+
 	mutex_lock(&delay_drop->lock);
 	err = mlx5_core_set_delay_drop(delay_drop->dev->mdev,
 				       delay_drop->timeout);
@@ -3651,12 +3654,107 @@ mlx5_ib_alloc_rdma_netdev(struct ib_device *hca,
 	return netdev;
 }
 
+static void delay_drop_debugfs_cleanup(struct mlx5_ib_dev *dev)
+{
+	if (!dev->delay_drop.dbg)
+		return;
+	debugfs_remove_recursive(dev->delay_drop.dbg->dir_debugfs);
+	kfree(dev->delay_drop.dbg);
+	dev->delay_drop.dbg = NULL;
+}
+
 static void cancel_delay_drop(struct mlx5_ib_dev *dev)
 {
 	if (!(dev->ib_dev.attrs.raw_packet_caps & IB_RAW_PACKET_CAP_DELAY_DROP))
 		return;
 
 	cancel_work_sync(&dev->delay_drop.delay_drop_work);
+	delay_drop_debugfs_cleanup(dev);
+}
+
+static ssize_t delay_drop_timeout_read(struct file *filp, char __user *buf,
+				       size_t count, loff_t *pos)
+{
+	struct mlx5_ib_delay_drop *delay_drop = filp->private_data;
+	char lbuf[20];
+	int len;
+
+	len = snprintf(lbuf, sizeof(lbuf), "%u\n", delay_drop->timeout);
+	return simple_read_from_buffer(buf, count, pos, lbuf, len);
+}
+
+static ssize_t delay_drop_timeout_write(struct file *filp, const char __user *buf,
+					size_t count, loff_t *pos)
+{
+	struct mlx5_ib_delay_drop *delay_drop = filp->private_data;
+	u32 timeout;
+	u32 var;
+
+	if (kstrtouint_from_user(buf, count, 0, &var))
+		return -EFAULT;
+
+	timeout = min_t(u32, roundup(var, 100), MLX5_MAX_DELAY_DROP_TIMEOUT_MS *
+			1000);
+	if (timeout != var)
+		mlx5_ib_dbg(delay_drop->dev, "Round delay drop timeout to %u usec\n",
+			    timeout);
+
+	delay_drop->timeout = timeout;
+
+	return count;
+}
+
+static const struct file_operations fops_delay_drop_timeout = {
+	.owner	= THIS_MODULE,
+	.open	= simple_open,
+	.write	= delay_drop_timeout_write,
+	.read	= delay_drop_timeout_read,
+};
+
+static int delay_drop_debugfs_init(struct mlx5_ib_dev *dev)
+{
+	struct mlx5_ib_dbg_delay_drop *dbg;
+
+	if (!mlx5_debugfs_root)
+		return 0;
+
+	dbg = kzalloc(sizeof(*dbg), GFP_KERNEL);
+	if (!dbg)
+		return -ENOMEM;
+
+	dbg->dir_debugfs =
+		debugfs_create_dir("delay_drop",
+				   dev->mdev->priv.dbg_root);
+	if (!dbg->dir_debugfs)
+		return -ENOMEM;
+
+	dbg->events_cnt_debugfs =
+		debugfs_create_atomic_t("num_timeout_events", 0400,
+					dbg->dir_debugfs,
+					&dev->delay_drop.events_cnt);
+	if (!dbg->events_cnt_debugfs)
+		goto out_debugfs;
+
+	dbg->rqs_cnt_debugfs =
+		debugfs_create_atomic_t("num_rqs", 0400,
+					dbg->dir_debugfs,
+					&dev->delay_drop.rqs_cnt);
+	if (!dbg->rqs_cnt_debugfs)
+		goto out_debugfs;
+
+	dbg->timeout_debugfs =
+		debugfs_create_file("timeout", 0600,
+				    dbg->dir_debugfs,
+				    &dev->delay_drop,
+				    &fops_delay_drop_timeout);
+	if (!dbg->timeout_debugfs)
+		goto out_debugfs;
+
+	return 0;
+
+out_debugfs:
+	delay_drop_debugfs_cleanup(dev);
+	return -ENOMEM;
 }
 
 static void init_delay_drop(struct mlx5_ib_dev *dev)
@@ -3669,6 +3767,11 @@ static void init_delay_drop(struct mlx5_ib_dev *dev)
 	dev->delay_drop.activate = false;
 	dev->delay_drop.timeout = MLX5_MAX_DELAY_DROP_TIMEOUT_MS * 1000;
 	INIT_WORK(&dev->delay_drop.delay_drop_work, delay_drop_handler);
+	atomic_set(&dev->delay_drop.rqs_cnt, 0);
+	atomic_set(&dev->delay_drop.events_cnt, 0);
+
+	if (delay_drop_debugfs_init(dev))
+		mlx5_ib_warn(dev, "Failed to init delay drop debugfs\n");
 }
 
 static void *mlx5_ib_add(struct mlx5_core_dev *mdev)