[PATCH 7.1.y 2/2] crypto: iaa - unmap dst before software fallback on decompress

[Sasha Levin <sashal@kernel.org>]

From: Vinicius Costa Gomes <vinicius.gomes@intel.com>

[ Upstream commit 94a25930477113730372e0fa2985da4c5ac95c9a ]

On a hardware analytics error, decompress retries through the software
fallback, which writes req->dst with the CPU while it is still mapped
DMA_FROM_DEVICE. With SWIOTLB active the later dma_unmap_sg() copies the
stale bounce buffer over req->dst, corrupting the result.

Unmap before the fallback runs. The async path unmaps inline; the sync
path signals the retry with -EAGAIN so iaa_comp_adecompress() runs the
fallback after unmapping.

Fixes: 2ec6761df889 ("crypto: iaa - Add support for deflate-iaa compression algorithm")
Cc: stable@vger.kernel.org
Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
[ adapted unavailable iaa_unmap_src() calls to single-entry dma_unmap_sg() calls ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/crypto/intel/iaa/iaa_crypto_main.c | 27 ++++++++++------------
 1 file changed, 12 insertions(+), 15 deletions(-)

diff --git a/drivers/crypto/intel/iaa/iaa_crypto_main.c b/drivers/crypto/intel/iaa/iaa_crypto_main.c
index 904d9413ba182..cdfe00464fa36 100644
--- a/drivers/crypto/intel/iaa/iaa_crypto_main.c
+++ b/drivers/crypto/intel/iaa/iaa_crypto_main.c
@@ -1058,13 +1058,17 @@ static void iaa_desc_complete(struct idxd_desc *idxd_desc,
 			pr_warn("%s: falling back to deflate-generic decompress, "
 				"analytics error code %x\n", __func__,
 				idxd_desc->iax_completion->error_code);
+			dma_unmap_sg(dev, ctx->req->dst, sg_nents(ctx->req->dst),
+				     DMA_FROM_DEVICE);
+			dma_unmap_sg(dev, ctx->req->src, 1, DMA_TO_DEVICE);
+
 			ret = deflate_generic_decompress(ctx->req);
 			if (ret) {
 				dev_dbg(dev, "%s: deflate-generic failed ret=%d\n",
 					__func__, ret);
 				err = -EIO;
-				goto err;
 			}
+			goto out;
 		} else {
 			err = -EIO;
 			goto err;
@@ -1447,19 +1451,9 @@ static int iaa_decompress(struct crypto_tfm *tfm, struct acomp_req *req,
 	ret = check_completion(dev, idxd_desc->iax_completion, false, false);
 	if (ret) {
 		dev_dbg(dev, "%s: check_completion failed ret=%d\n", __func__, ret);
-		if (idxd_desc->iax_completion->status == IAA_ANALYTICS_ERROR) {
-			pr_warn("%s: falling back to deflate-generic decompress, "
-				"analytics error code %x\n", __func__,
-				idxd_desc->iax_completion->error_code);
-			ret = deflate_generic_decompress(req);
-			if (ret) {
-				dev_dbg(dev, "%s: deflate-generic failed ret=%d\n",
-					__func__, ret);
-				goto err;
-			}
-		} else {
-			goto err;
-		}
+		if (idxd_desc->iax_completion->status == IAA_ANALYTICS_ERROR)
+			ret = -EAGAIN;
+		goto err;
 	} else {
 		req->dlen = idxd_desc->iax_completion->output_size;
 	}
@@ -1647,13 +1641,16 @@ static int iaa_comp_adecompress(struct acomp_req *req)
 	if (ret == -EINPROGRESS)
 		return ret;
 
-	if (ret != 0)
+	if (ret != 0 && ret != -EAGAIN)
 		dev_dbg(dev, "asynchronous decompress failed ret=%d\n", ret);
 
 	dma_unmap_sg(dev, req->dst, 1, DMA_FROM_DEVICE);
 	dma_unmap_sg(dev, req->src, 1, DMA_TO_DEVICE);
 	iaa_wq_put(wq);
 
+	if (ret == -EAGAIN)
+		ret = deflate_generic_decompress(req);
+
 	return ret;
 }
 
-- 
2.53.0