crypto: caam - fix hash context DMA unmap size

When driver started using state->caam_ctxt for storing both running hash
and final hash, it was not updated to handle different DMA unmap
lengths.

Cc: <stable@vger.kernel.org> # v4.19+
Fixes: c19650d6 ("crypto: caam - fix DMA mapping of stack memory")
Signed-off-by: Franck LENORMAND <franck.lenormand@nxp.com>
Signed-off-by: Horia Geantă <horia.geanta@nxp.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/caam/caamhash.c

@@ -114,6 +114,7 @@ struct caam_hash_ctx {
 struct caam_hash_state {
 	dma_addr_t buf_dma;
 	dma_addr_t ctx_dma;
+	int ctx_dma_len;
 	u8 buf_0[CAAM_MAX_HASH_BLOCK_SIZE] ____cacheline_aligned;
 	int buflen_0;
 	u8 buf_1[CAAM_MAX_HASH_BLOCK_SIZE] ____cacheline_aligned;
@@ -171,6 +172,7 @@ static inline int map_seq_out_ptr_ctx(u32 *desc, struct device *jrdev,
 				      struct caam_hash_state *state,
 				      int ctx_len)
 {
+	state->ctx_dma_len = ctx_len;
 	state->ctx_dma = dma_map_single(jrdev, state->caam_ctx,
 					ctx_len, DMA_FROM_DEVICE);
 	if (dma_mapping_error(jrdev, state->ctx_dma)) {
@@ -212,6 +214,7 @@ static inline int ctx_map_to_sec4_sg(struct device *jrdev,
 				     struct caam_hash_state *state, int ctx_len,
 				     struct sec4_sg_entry *sec4_sg, u32 flag)
 {
+	state->ctx_dma_len = ctx_len;
 	state->ctx_dma = dma_map_single(jrdev, state->caam_ctx, ctx_len, flag);
 	if (dma_mapping_error(jrdev, state->ctx_dma)) {
 		dev_err(jrdev, "unable to map ctx\n");
@@ -594,12 +597,10 @@ static inline void ahash_unmap_ctx(struct device *dev,
 			struct ahash_edesc *edesc,
 			struct ahash_request *req, int dst_len, u32 flag)
 {
-	struct crypto_ahash *ahash = crypto_ahash_reqtfm(req);
-	struct caam_hash_ctx *ctx = crypto_ahash_ctx(ahash);
 	struct caam_hash_state *state = ahash_request_ctx(req);
 
 	if (state->ctx_dma) {
-		dma_unmap_single(dev, state->ctx_dma, ctx->ctx_len, flag);
+		dma_unmap_single(dev, state->ctx_dma, state->ctx_dma_len, flag);
 		state->ctx_dma = 0;
 	}
 	ahash_unmap(dev, edesc, req, dst_len);
@@ -1580,6 +1581,7 @@ static int ahash_init(struct ahash_request *req)
 	state->final = ahash_final_no_ctx;
 
 	state->ctx_dma = 0;
+	state->ctx_dma_len = 0;
 	state->current_buf = 0;
 	state->buf_dma = 0;
 	state->buflen_0 = 0;