[PATCH] crypto: octeontx2 - Use dma_alloc_coherent() instead of kzalloc/dma_map_single()

[PATCH] crypto: octeontx2 - Use dma_alloc_coherent() instead of kzalloc/dma_map_single()

[Cai Huoqing]

Replacing kzalloc/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.

Signed-off-by: Cai Huoqing <caihuoqing@baidu.com>
---
 drivers/crypto/marvell/octeontx2/otx2_cptpf_ucode.c | 13 ++-----------
 1 file changed, 2 insertions(+), 11 deletions(-)

diff --git a/drivers/crypto/marvell/octeontx2/otx2_cptpf_ucode.c b/drivers/crypto/marvell/octeontx2/otx2_cptpf_ucode.c
index dff34b3ec09e..60d62ce049a6 100644
--- a/drivers/crypto/marvell/octeontx2/otx2_cptpf_ucode.c
+++ b/drivers/crypto/marvell/octeontx2/otx2_cptpf_ucode.c
@@ -1449,18 +1449,11 @@ int otx2_cpt_discover_eng_capabilities(struct otx2_cptpf_dev *cptpf)
 	compl_rlen = ALIGN(sizeof(union otx2_cpt_res_s), OTX2_CPT_DMA_MINALIGN);
 	len = compl_rlen + LOADFVC_RLEN;
 
-	result = kzalloc(len, GFP_KERNEL);
+	result = dma_alloc_coherent(&pdev->dev, len, &rptr_baddr, GFP_KERNEL);
 	if (!result) {
 		ret = -ENOMEM;
 		goto lf_cleanup;
 	}
-	rptr_baddr = dma_map_single(&pdev->dev, (void *)result, len,
-				    DMA_BIDIRECTIONAL);
-	if (dma_mapping_error(&pdev->dev, rptr_baddr)) {
-		dev_err(&pdev->dev, "DMA mapping failed\n");
-		ret = -EFAULT;
-		goto free_result;
-	}
 	rptr = (u8 *)result + compl_rlen;
 
 	/* Fill in the command */
@@ -1489,11 +1482,9 @@ int otx2_cpt_discover_eng_capabilities(struct otx2_cptpf_dev *cptpf)
 
 		cptpf->eng_caps[etype].u = be64_to_cpup(rptr);
 	}
-	dma_unmap_single(&pdev->dev, rptr_baddr, len, DMA_BIDIRECTIONAL);
+	dma_free_coherent(&pdev->dev, len, (void *)result, rptr_baddr);
 	cptpf->is_eng_caps_discovered = true;
 
-free_result:
-	kfree(result);
 lf_cleanup:
 	otx2_cptlf_shutdown(&cptpf->lfs);
 delete_grps:
-- 
2.25.1

Re: [PATCH] crypto: octeontx2 - Use dma_alloc_coherent() instead of kzalloc/dma_map_single()

[Christoph Hellwig]

On Mon, Oct 11, 2021 at 12:00:04AM +0800, Cai Huoqing wrote:
> Replacing kzalloc/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.

As just explained in another patch like this please qualify the
savings as we have actual results that shows the reverse of your claims.