From: Saeed Mahameed <saeedm@mellanox.com>
Date: Tue, 10 Mar 2020 10:22:29 +0200
Subject: RDMA/mlx5: Replace spinlock protected write with atomic var
Patch-mainline: v5.7-rc1
Git-commit: f743ff3b37dfc8e8cf4a32d4254cddd5f0f1add8
References: jsc#SLE-15175

mkey variant calculation was spinlock protected to make it atomic, replace
that with one atomic variable.

Link: https://lore.kernel.org/r/20200310082238.239865-4-leon@kernel.org
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/infiniband/hw/mlx5/main.c    |    2 +-
 drivers/infiniband/hw/mlx5/mlx5_ib.h |    5 +----
 drivers/infiniband/hw/mlx5/mr.c      |    6 +-----
 3 files changed, 3 insertions(+), 10 deletions(-)

--- a/drivers/infiniband/hw/mlx5/main.c
+++ b/drivers/infiniband/hw/mlx5/main.c
@@ -6391,7 +6391,7 @@ static int mlx5_ib_stage_init_init(struc
 	spin_lock_init(&dev->reset_flow_resource_lock);
 	xa_init(&dev->odp_mkeys);
 	xa_init(&dev->sig_mrs);
-	spin_lock_init(&dev->mkey_lock);
+	atomic_set(&dev->mkey_var, 0);
 
 	spin_lock_init(&dev->dm.lock);
 	dev->dm.dev = mdev;
--- a/drivers/infiniband/hw/mlx5/mlx5_ib.h
+++ b/drivers/infiniband/hw/mlx5/mlx5_ib.h
@@ -996,10 +996,7 @@ struct mlx5_ib_dev {
 	 */
 	struct mlx5_ib_resources	devr;
 
-	/* protect mkey key part */
-	spinlock_t			mkey_lock;
-	u8				mkey_key;
-
+	atomic_t			mkey_var;
 	struct mlx5_mr_cache		cache;
 	struct timer_list		delay_timer;
 	/* Prevents soft lock on massive reg MRs */
--- a/drivers/infiniband/hw/mlx5/mr.c
+++ b/drivers/infiniband/hw/mlx5/mr.c
@@ -54,12 +54,8 @@ static void
 assign_mkey_variant(struct mlx5_ib_dev *dev, struct mlx5_core_mkey *mkey,
 		    u32 *in)
 {
+	u8 key = atomic_inc_return(&dev->mkey_var);
 	void *mkc;
-	u8 key;
-
-	spin_lock_irq(&dev->mkey_lock);
-	key = dev->mkey_key++;
-	spin_unlock_irq(&dev->mkey_lock);
 
 	mkc = MLX5_ADDR_OF(create_mkey_in, in, memory_key_mkey_entry);
 	MLX5_SET(mkc, mkc, mkey_7_0, key);