crypto: caam - check if RNG job failed

We shouldn't stay silent if RNG job fails. Add appropriate code to
check for that case and propagate error code up appropriately.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Reviewed-by: Horia Geantă <horia.geanta@nxp.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Horia Geantă <horia.geanta@nxp.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Iuliana Prodan <iuliana.prodan@nxp.com>
Cc: linux-crypto@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-imx@nxp.com
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/caam/caamrng.c

@@ -44,6 +44,11 @@ struct caam_rng_ctx {
 	struct kfifo fifo;
 };
 
+struct caam_rng_job_ctx {
+	struct completion *done;
+	int *err;
+};
+
 static struct caam_rng_ctx *to_caam_rng_ctx(struct hwrng *r)
 {
 	return (struct caam_rng_ctx *)r->priv;
@@ -52,12 +57,12 @@ static struct caam_rng_ctx *to_caam_rng_ctx(struct hwrng *r)
 static void caam_rng_done(struct device *jrdev, u32 *desc, u32 err,
 			  void *context)
 {
-	struct completion *done = context;
+	struct caam_rng_job_ctx *jctx = context;
 
 	if (err)
-		caam_jr_strstatus(jrdev, err);
+		*jctx->err = caam_jr_strstatus(jrdev, err);
 
-	complete(done);
+	complete(jctx->done);
 }
 
 static u32 *caam_init_desc(u32 *desc, dma_addr_t dst_dma, int len)
@@ -80,7 +85,11 @@ static int caam_rng_read_one(struct device *jrdev,
 			     struct completion *done)
 {
 	dma_addr_t dst_dma;
-	int err;
+	int err, ret = 0;
+	struct caam_rng_job_ctx jctx = {
+		.done = done,
+		.err  = &ret,
+	};
 
 	len = min_t(int, len, CAAM_RNG_MAX_FIFO_STORE_SIZE);
 
@@ -93,15 +102,15 @@ static int caam_rng_read_one(struct device *jrdev,
 	init_completion(done);
 	err = caam_jr_enqueue(jrdev,
 			      caam_init_desc(desc, dst_dma, len),
-			      caam_rng_done, done);
+			      caam_rng_done, &jctx);
 	if (err == -EINPROGRESS) {
 		wait_for_completion(done);
 		err = 0;
 	}
 
 	dma_unmap_single(jrdev, dst_dma, len, DMA_FROM_DEVICE);
 
-	return err ?: len;
+	return err ?: (ret ?: len);
 }
 
 static void caam_rng_fill_async(struct caam_rng_ctx *ctx)