crypto: qat - remove dma_free_coherent() for DH

The functions qat_dh_compute_value() allocates memory with
dma_alloc_coherent() if the source or the destination buffers are made
of multiple flat buffers or of a size that is not compatible with the
hardware.
This memory is then freed with dma_free_coherent() in the context of a
tasklet invoked to handle the response for the corresponding request.

According to Documentation/core-api/dma-api-howto.rst, the function
dma_free_coherent() cannot be called in an interrupt context.

Replace allocations with dma_alloc_coherent() in the function
qat_dh_compute_value() with kmalloc() + dma_map_single().

Cc: stable@vger.kernel.org
Fixes: c9839143eb ("crypto: qat - Add DH support")
Signed-off-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Reviewed-by: Adam Guerin <adam.guerin@intel.com>
Reviewed-by: Wojciech Ziemba <wojciech.ziemba@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/qat/qat_common/qat_asym_algs.c

@@ -164,25 +164,20 @@ static void qat_dh_cb(struct icp_qat_fw_pke_resp *resp)
 	err = (err == ICP_QAT_FW_COMN_STATUS_FLAG_OK) ? 0 : -EINVAL;
 
 	if (areq->src) {
-		if (req->src_align)
-			dma_free_coherent(dev, req->ctx.dh->p_size,
-					  req->src_align, req->in.dh.in.b);
-		else
-			dma_unmap_single(dev, req->in.dh.in.b,
-					 req->ctx.dh->p_size, DMA_TO_DEVICE);
+		dma_unmap_single(dev, req->in.dh.in.b, req->ctx.dh->p_size,
+				 DMA_TO_DEVICE);
+		kfree_sensitive(req->src_align);
 	}
 
 	areq->dst_len = req->ctx.dh->p_size;
 	if (req->dst_align) {
 		scatterwalk_map_and_copy(req->dst_align, areq->dst, 0,
 					 areq->dst_len, 1);
+		kfree_sensitive(req->dst_align);
+	}
 
-		dma_free_coherent(dev, req->ctx.dh->p_size, req->dst_align,
-				  req->out.dh.r);
-	} else {
 	dma_unmap_single(dev, req->out.dh.r, req->ctx.dh->p_size,
 			 DMA_FROM_DEVICE);
-	}
 
 	dma_unmap_single(dev, req->phy_in, sizeof(struct qat_dh_input_params),
 			 DMA_TO_DEVICE);
@@ -231,6 +226,7 @@ static int qat_dh_compute_value(struct kpp_request *req)
 	struct icp_qat_fw_pke_request *msg = &qat_req->req;
 	int ret;
 	int n_input_params = 0;
+	u8 *vaddr;
 
 	if (unlikely(!ctx->xa))
 		return -EINVAL;
@@ -287,27 +283,24 @@ static int qat_dh_compute_value(struct kpp_request *req)
 		 */
 		if (sg_is_last(req->src) && req->src_len == ctx->p_size) {
 			qat_req->src_align = NULL;
-			qat_req->in.dh.in.b = dma_map_single(dev,
-							     sg_virt(req->src),
-							     req->src_len,
-							     DMA_TO_DEVICE);
-			if (unlikely(dma_mapping_error(dev,
-						       qat_req->in.dh.in.b)))
-				return ret;
-
+			vaddr = sg_virt(req->src);
 		} else {
 			int shift = ctx->p_size - req->src_len;
 
-			qat_req->src_align = dma_alloc_coherent(dev,
-								ctx->p_size,
-								&qat_req->in.dh.in.b,
-								GFP_KERNEL);
+			qat_req->src_align = kzalloc(ctx->p_size, GFP_KERNEL);
 			if (unlikely(!qat_req->src_align))
 				return ret;
 
 			scatterwalk_map_and_copy(qat_req->src_align + shift,
 						 req->src, 0, req->src_len, 0);
+
+			vaddr = qat_req->src_align;
 		}
+
+		qat_req->in.dh.in.b = dma_map_single(dev, vaddr, ctx->p_size,
+						     DMA_TO_DEVICE);
+		if (unlikely(dma_mapping_error(dev, qat_req->in.dh.in.b)))
+			goto unmap_src;
 	}
 	/*
 	 * dst can be of any size in valid range, but HW expects it to be the
@@ -318,20 +311,18 @@ static int qat_dh_compute_value(struct kpp_request *req)
 	 */
 	if (sg_is_last(req->dst) && req->dst_len == ctx->p_size) {
 		qat_req->dst_align = NULL;
-		qat_req->out.dh.r = dma_map_single(dev, sg_virt(req->dst),
-						   req->dst_len,
-						   DMA_FROM_DEVICE);
-
-		if (unlikely(dma_mapping_error(dev, qat_req->out.dh.r)))
-			goto unmap_src;
-
+		vaddr = sg_virt(req->dst);
 	} else {
-		qat_req->dst_align = dma_alloc_coherent(dev, ctx->p_size,
-							&qat_req->out.dh.r,
-							GFP_KERNEL);
+		qat_req->dst_align = kzalloc(ctx->p_size, GFP_KERNEL);
 		if (unlikely(!qat_req->dst_align))
 			goto unmap_src;
+
+		vaddr = qat_req->dst_align;
 	}
+	qat_req->out.dh.r = dma_map_single(dev, vaddr, ctx->p_size,
+					   DMA_FROM_DEVICE);
+	if (unlikely(dma_mapping_error(dev, qat_req->out.dh.r)))
+		goto unmap_dst;
 
 	qat_req->in.dh.in_tab[n_input_params] = 0;
 	qat_req->out.dh.out_tab[1] = 0;
@@ -371,23 +362,17 @@ unmap_in_params:
 				 sizeof(struct qat_dh_input_params),
 				 DMA_TO_DEVICE);
 unmap_dst:
-	if (qat_req->dst_align)
-		dma_free_coherent(dev, ctx->p_size, qat_req->dst_align,
-				  qat_req->out.dh.r);
-	else
 	if (!dma_mapping_error(dev, qat_req->out.dh.r))
 		dma_unmap_single(dev, qat_req->out.dh.r, ctx->p_size,
 				 DMA_FROM_DEVICE);
+	kfree_sensitive(qat_req->dst_align);
 unmap_src:
 	if (req->src) {
-		if (qat_req->src_align)
-			dma_free_coherent(dev, ctx->p_size, qat_req->src_align,
-					  qat_req->in.dh.in.b);
-		else
 		if (!dma_mapping_error(dev, qat_req->in.dh.in.b))
 			dma_unmap_single(dev, qat_req->in.dh.in.b,
 					 ctx->p_size,
 					 DMA_TO_DEVICE);
+		kfree_sensitive(qat_req->src_align);
 	}
 	return ret;
 }