From 4d6dbe056721005c491d4776f029b4eb83d42f7c Mon Sep 17 00:00:00 2001
From: hselasky <hselasky@FreeBSD.org>
Date: Wed, 8 May 2019 10:30:18 +0000
Subject: [PATCH] Disable all MSIX interrupts before shutdown in mlx5.

Make sure the interrupt handlers don't race with the fast unload one
code in the shutdown handler.

MFC after:	3 days
Sponsored by:	Mellanox Technologies
---
 sys/dev/mlx5/driver.h              |  1 +
 sys/dev/mlx5/mlx5_core/mlx5_cmd.c  |  3 +++
 sys/dev/mlx5/mlx5_core/mlx5_eq.c   |  4 +++-
 sys/dev/mlx5/mlx5_core/mlx5_main.c | 19 +++++++++++++++++++
 4 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/sys/dev/mlx5/driver.h b/sys/dev/mlx5/driver.h
index a8719b57cebb..af418d955dd8 100644
--- a/sys/dev/mlx5/driver.h
+++ b/sys/dev/mlx5/driver.h
@@ -606,6 +606,7 @@ struct mlx5_priv {
 	struct mlx5_irq_info	*irq_info;
 	struct mlx5_uuar_info	uuari;
 	MLX5_DECLARE_DOORBELL_LOCK(cq_uar_lock);
+	int			disable_irqs;
 
 	struct io_mapping	*bf_mapping;
 
diff --git a/sys/dev/mlx5/mlx5_core/mlx5_cmd.c b/sys/dev/mlx5/mlx5_core/mlx5_cmd.c
index 03d4615de6f5..666b473c2391 100644
--- a/sys/dev/mlx5/mlx5_core/mlx5_cmd.c
+++ b/sys/dev/mlx5/mlx5_core/mlx5_cmd.c
@@ -1143,6 +1143,9 @@ static void mlx5_cmd_change_mod(struct mlx5_core_dev *dev, int mode)
 	struct mlx5_cmd *cmd = &dev->cmd;
 	int i;
 
+	if (cmd->mode == mode)
+		return;
+
 	for (i = 0; i < cmd->max_reg_cmds; i++)
 		down(&cmd->sem);
 
diff --git a/sys/dev/mlx5/mlx5_core/mlx5_eq.c b/sys/dev/mlx5/mlx5_core/mlx5_eq.c
index 18b7ca481569..f3ab960e54f1 100644
--- a/sys/dev/mlx5/mlx5_core/mlx5_eq.c
+++ b/sys/dev/mlx5/mlx5_core/mlx5_eq.c
@@ -395,7 +395,9 @@ static irqreturn_t mlx5_msix_handler(int irq, void *eq_ptr)
 	struct mlx5_eq *eq = eq_ptr;
 	struct mlx5_core_dev *dev = eq->dev;
 
-	mlx5_eq_int(dev, eq);
+	/* check if IRQs are not disabled */
+	if (likely(dev->priv.disable_irqs == 0))
+		mlx5_eq_int(dev, eq);
 
 	/* MSI-X vectors always belong to us */
 	return IRQ_HANDLED;
diff --git a/sys/dev/mlx5/mlx5_core/mlx5_main.c b/sys/dev/mlx5/mlx5_core/mlx5_main.c
index 3dfa4583cdcd..9a360a3afa9e 100644
--- a/sys/dev/mlx5/mlx5_core/mlx5_main.c
+++ b/sys/dev/mlx5/mlx5_core/mlx5_main.c
@@ -35,6 +35,7 @@
 #include <linux/slab.h>
 #include <linux/io-mapping.h>
 #include <linux/interrupt.h>
+#include <linux/hardirq.h>
 #include <dev/mlx5/driver.h>
 #include <dev/mlx5/cq.h>
 #include <dev/mlx5/qp.h>
@@ -1443,12 +1444,30 @@ static int mlx5_try_fast_unload(struct mlx5_core_dev *dev)
 	return 0;
 }
 
+static void mlx5_disable_interrupts(struct mlx5_core_dev *mdev)
+{
+	int nvec = mdev->priv.eq_table.num_comp_vectors + MLX5_EQ_VEC_COMP_BASE;
+	int x;
+
+	mdev->priv.disable_irqs = 1;
+
+	/* wait for all IRQ handlers to finish processing */
+	for (x = 0; x != nvec; x++)
+		synchronize_irq(mdev->priv.msix_arr[x].vector);
+}
+
 static void shutdown_one(struct pci_dev *pdev)
 {
 	struct mlx5_core_dev *dev  = pci_get_drvdata(pdev);
 	struct mlx5_priv *priv = &dev->priv;
 	int err;
 
+	/* enter polling mode */
+	mlx5_cmd_use_polling(dev);
+
+	/* disable all interrupts */
+	mlx5_disable_interrupts(dev);
+
 	err = mlx5_try_fast_unload(dev);
 	if (err)
 	        mlx5_unload_one(dev, priv, false);