From: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Date: Tue, 19 Nov 2019 13:42:56 +0800
Subject: crypto: hisilicon - Fix issue with wrong number of sg elements after
 dma map
Git-commit: 8debacd60c69beab80736d4af4feca47c2e2bd9e
Patch-mainline: v5.6-rc1
References: jsc#SLE-16507 jsc#SLE-15835

We fill the hardware scatter gather list assuming it will need the same
number of elements at the original scatterlist. If an IOMMU is involved,
then it may well need fewer. The return value of dma_map_sg tells us how
many.

Probably never caused visible problems as the hardware won't get to
the elements that are incorrect before it finds enough space.

Fixes: dfed0098ab91 (crypto: hisilicon - add hardware SGL support)
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Zhou Wang <wangzhou1@hisilicon.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Matthias Brugger <mbrugger@suse.com>
---
 drivers/crypto/hisilicon/sgl.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/drivers/crypto/hisilicon/sgl.c b/drivers/crypto/hisilicon/sgl.c
index 012023c347b1..1e153a0d7c10 100644
--- a/drivers/crypto/hisilicon/sgl.c
+++ b/drivers/crypto/hisilicon/sgl.c
@@ -202,18 +202,21 @@ hisi_acc_sg_buf_map_to_hw_sgl(struct device *dev,
 	dma_addr_t curr_sgl_dma = 0;
 	struct acc_hw_sge *curr_hw_sge;
 	struct scatterlist *sg;
-	int i, ret, sg_n;
+	int i, sg_n, sg_n_mapped;
 
 	if (!dev || !sgl || !pool || !hw_sgl_dma)
 		return ERR_PTR(-EINVAL);
 
 	sg_n = sg_nents(sgl);
-	if (sg_n > pool->sge_nr)
+
+	sg_n_mapped = dma_map_sg(dev, sgl, sg_n, DMA_BIDIRECTIONAL);
+	if (!sg_n_mapped)
 		return ERR_PTR(-EINVAL);
 
-	ret = dma_map_sg(dev, sgl, sg_n, DMA_BIDIRECTIONAL);
-	if (!ret)
+	if (sg_n_mapped > pool->sge_nr) {
+		dma_unmap_sg(dev, sgl, sg_n, DMA_BIDIRECTIONAL);
 		return ERR_PTR(-EINVAL);
+	}
 
 	curr_hw_sgl = acc_get_sgl(pool, index, &curr_sgl_dma);
 	if (IS_ERR(curr_hw_sgl)) {
@@ -224,7 +227,7 @@ hisi_acc_sg_buf_map_to_hw_sgl(struct device *dev,
 	curr_hw_sgl->entry_length_in_sgl = cpu_to_le16(pool->sge_nr);
 	curr_hw_sge = curr_hw_sgl->sge_entries;
 
-	for_each_sg(sgl, sg, sg_n, i) {
+	for_each_sg(sgl, sg, sg_n_mapped, i) {
 		sg_map_to_hw_sg(sg, curr_hw_sge);
 		inc_hw_sgl_sge(curr_hw_sgl);
 		curr_hw_sge++;
-- 
2.29.2