From: Alexander Lobakin <alobakin@dlink.ru>
Date: Mon, 17 Feb 2020 10:36:29 +0300
Subject: IB/mlx5: Optimize u64 division on 32-bit arches
Patch-mainline: v5.7-rc1
Git-commit: 91b74bf5310b22ac3286d8e9b5354b77f41af178
References: jsc#SLE-8446

Commit f164be8c0366 ("IB/mlx5: Extend caps stage to handle VAR
capabilities") introduced a straight "/" division of the u64 variable
"bar_size".

This was fixed with commit 685eff513183 ("IB/mlx5: Use div64_u64 for
num_var_hw_entries calculation"). However, div64_u64() is redundant here
as mlx5_var_table::stride_size is of type u32.  Make the actual code way
more optimized on 32-bit kernels using div_u64() and fix 80 chars
break-through by the way.

Fixes: 685eff513183 ("IB/mlx5: Use div64_u64 for num_var_hw_entries calculation")
Link: https://lore.kernel.org/r/20200217073629.8051-1-alobakin@dlink.ru
Signed-off-by: Alexander Lobakin <alobakin@dlink.ru>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/infiniband/hw/mlx5/main.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/infiniband/hw/mlx5/main.c
+++ b/drivers/infiniband/hw/mlx5/main.c
@@ -6545,7 +6545,8 @@ static int mlx5_ib_init_var_table(struct
 					doorbell_bar_offset);
 	bar_size = (1ULL << log_doorbell_bar_size) * 4096;
 	var_table->stride_size = 1ULL << log_doorbell_stride;
-	var_table->num_var_hw_entries = div64_u64(bar_size, var_table->stride_size);
+	var_table->num_var_hw_entries = div_u64(bar_size,
+						var_table->stride_size);
 	mutex_init(&var_table->bitmap_lock);
 	var_table->bitmap = bitmap_zalloc(var_table->num_var_hw_entries,
 					  GFP_KERNEL);