From: Cai Huoqing <caihuoqing@baidu.com>
Date: Sun, 26 Sep 2021 14:11:15 +0800
Subject: RDMA/hns: Use dma_alloc_coherent() instead of
 kmalloc/dma_map_single()
Patch-mainline: v5.16-rc1
Git-commit: 9a33f3980978e420672b0b54e3fa0c7908fd7c78
References: bsc#1190336

Replacing kmalloc/kfree/dma_map_single/dma_unmap_single() with
dma_alloc_coherent/dma_free_coherent() helps to reduce code size, and
simplify the code, and coherent DMA will not clear the cache every time.

The SOC that this driver supports does not have incoherent DMA, so this
makes the code follow the DMA API properly with no performance
impact. Currently there are missing dma sync calls around the DMA
transfers.

Link: https://lore.kernel.org/r/20210926061116.282-1-caihuoqing@baidu.com
Signed-off-by: Cai Huoqing <caihuoqing@baidu.com>
Reviewed-by: Wenpeng Liang <liangwenpeng@huawei.com>
Tested-by: Wenpeng Liang <liangwenpeng@huawei.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/infiniband/hw/hns/hns_roce_hw_v2.c |   20 +++++---------------
 1 file changed, 5 insertions(+), 15 deletions(-)

--- a/drivers/infiniband/hw/hns/hns_roce_hw_v2.c
+++ b/drivers/infiniband/hw/hns/hns_roce_hw_v2.c
@@ -1165,32 +1165,22 @@ static int hns_roce_alloc_cmq_desc(struc
 {
 	int size = ring->desc_num * sizeof(struct hns_roce_cmq_desc);
 
-	ring->desc = kzalloc(size, GFP_KERNEL);
+	ring->desc = dma_alloc_coherent(hr_dev->dev, size,
+					&ring->desc_dma_addr, GFP_KERNEL);
 	if (!ring->desc)
 		return -ENOMEM;
 
-	ring->desc_dma_addr = dma_map_single(hr_dev->dev, ring->desc, size,
-					     DMA_BIDIRECTIONAL);
-	if (dma_mapping_error(hr_dev->dev, ring->desc_dma_addr)) {
-		ring->desc_dma_addr = 0;
-		kfree(ring->desc);
-		ring->desc = NULL;
-
-		return -ENOMEM;
-	}
-
 	return 0;
 }
 
 static void hns_roce_free_cmq_desc(struct hns_roce_dev *hr_dev,
 				   struct hns_roce_v2_cmq_ring *ring)
 {
-	dma_unmap_single(hr_dev->dev, ring->desc_dma_addr,
-			 ring->desc_num * sizeof(struct hns_roce_cmq_desc),
-			 DMA_BIDIRECTIONAL);
+	dma_free_coherent(hr_dev->dev,
+			  ring->desc_num * sizeof(struct hns_roce_cmq_desc),
+			  ring->desc, ring->desc_dma_addr);
 
 	ring->desc_dma_addr = 0;
-	kfree(ring->desc);
 }
 
 static int init_csq(struct hns_roce_dev *hr_dev,