From: Ido Schimmel <idosch@mellanox.com>
Date: Thu, 20 Feb 2020 09:07:46 +0200
Subject: mlxsw: spectrum_kvdl: Protect allocations with a lock
Patch-mainline: v5.7-rc1
Git-commit: 48fe78cebdf6592ef1750647253101f3526c5b7b
References: bsc#1176774

The KVDL is used to store objects allocated throughout various places
in the driver. For example, both nexthops (adjacency entries) and ACL
actions are stored in the KVDL.

Currently, all allocations are protected by RTNL, but this is going to
change with the removal of RTNL from the routing code.

Therefore, protect KVDL allocations with a lock. A mutex is used since
the free operation can block in Spectrum-2.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/ethernet/mellanox/mlxsw/spectrum_kvdl.c |   16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_kvdl.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_kvdl.c
@@ -2,12 +2,14 @@
 /* Copyright (c) 2016-2018 Mellanox Technologies. All rights reserved */
 
 #include <linux/kernel.h>
+#include <linux/mutex.h>
 #include <linux/slab.h>
 
 #include "spectrum.h"
 
 struct mlxsw_sp_kvdl {
 	const struct mlxsw_sp_kvdl_ops *kvdl_ops;
+	struct mutex kvdl_lock; /* Protects kvdl allocations */
 	unsigned long priv[];
 	/* priv has to be always the last item */
 };
@@ -22,6 +24,7 @@ int mlxsw_sp_kvdl_init(struct mlxsw_sp *
 		       GFP_KERNEL);
 	if (!kvdl)
 		return -ENOMEM;
+	mutex_init(&kvdl->kvdl_lock);
 	kvdl->kvdl_ops = kvdl_ops;
 	mlxsw_sp->kvdl = kvdl;
 
@@ -31,6 +34,7 @@ int mlxsw_sp_kvdl_init(struct mlxsw_sp *
 	return 0;
 
 err_init:
+	mutex_destroy(&kvdl->kvdl_lock);
 	kfree(kvdl);
 	return err;
 }
@@ -40,6 +44,7 @@ void mlxsw_sp_kvdl_fini(struct mlxsw_sp
 	struct mlxsw_sp_kvdl *kvdl = mlxsw_sp->kvdl;
 
 	kvdl->kvdl_ops->fini(mlxsw_sp, kvdl->priv);
+	mutex_destroy(&kvdl->kvdl_lock);
 	kfree(kvdl);
 }
 
@@ -48,9 +53,14 @@ int mlxsw_sp_kvdl_alloc(struct mlxsw_sp
 			unsigned int entry_count, u32 *p_entry_index)
 {
 	struct mlxsw_sp_kvdl *kvdl = mlxsw_sp->kvdl;
+	int err;
+
+	mutex_lock(&kvdl->kvdl_lock);
+	err = kvdl->kvdl_ops->alloc(mlxsw_sp, kvdl->priv, type,
+				    entry_count, p_entry_index);
+	mutex_unlock(&kvdl->kvdl_lock);
 
-	return kvdl->kvdl_ops->alloc(mlxsw_sp, kvdl->priv, type,
-				     entry_count, p_entry_index);
+	return err;
 }
 
 void mlxsw_sp_kvdl_free(struct mlxsw_sp *mlxsw_sp,
@@ -59,8 +69,10 @@ void mlxsw_sp_kvdl_free(struct mlxsw_sp
 {
 	struct mlxsw_sp_kvdl *kvdl = mlxsw_sp->kvdl;
 
+	mutex_lock(&kvdl->kvdl_lock);
 	kvdl->kvdl_ops->free(mlxsw_sp, kvdl->priv, type,
 			     entry_count, entry_index);
+	mutex_unlock(&kvdl->kvdl_lock);
 }
 
 int mlxsw_sp_kvdl_alloc_count_query(struct mlxsw_sp *mlxsw_sp,