Received-SPF: pass (google.com: domain of linux-crypto-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   Peter Harliman Liem <pliem@maxlinear.com>
To:     <atenart@kernel.org>, <herbert@gondor.apana.org.au>
CC:     <linux-crypto@vger.kernel.org>, <linux-lgm-soc@maxlinear.com>,
        "Peter Harliman Liem" <pliem@maxlinear.com>
Subject: [PATCH v3 1/2] crypto: inside_secure - Avoid dma map if size is zero
Date:   Tue, 13 Sep 2022 16:03:47 +0800
Message-ID: <c10f8274fafd4f6afe92d0a2716ec5a38ca02cc8.1663055663.git.pliem@maxlinear.com>
MIME-Version: 1.0
Content-Type: text/plain
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

From commit d03c54419274 ("dma-mapping: disallow .map_sg
operations from returning zero on error"), dma_map_sg()
produces warning if size is 0. This results in visible
warnings if crypto length is zero.
To avoid that, we avoid calling dma_map_sg if size is zero.

Signed-off-by: Peter Harliman Liem <pliem@maxlinear.com>
---
v3:
 Remove fixes tag
 Add corresponding change for dma_unmap_sg
v2:
 Add fixes tag

 .../crypto/inside-secure/safexcel_cipher.c    | 44 +++++++++++++------
 1 file changed, 31 insertions(+), 13 deletions(-)

diff --git a/drivers/crypto/inside-secure/safexcel_cipher.c b/drivers/crypt=
o/inside-secure/safexcel_cipher.c
index d68ef16650d4..5a222c228c3b 100644
--- a/drivers/crypto/inside-secure/safexcel_cipher.c
+++ b/drivers/crypto/inside-secure/safexcel_cipher.c
@@ -642,10 +642,16 @@ static int safexcel_handle_req_result(struct safexcel=
_crypto_priv *priv, int rin
 =09safexcel_complete(priv, ring);
=20
 =09if (src =3D=3D dst) {
-=09=09dma_unmap_sg(priv->dev, src, sreq->nr_src, DMA_BIDIRECTIONAL);
+=09=09if (sreq->nr_src > 0)
+=09=09=09dma_unmap_sg(priv->dev, src, sreq->nr_src,
+=09=09=09=09     DMA_BIDIRECTIONAL);
 =09} else {
-=09=09dma_unmap_sg(priv->dev, src, sreq->nr_src, DMA_TO_DEVICE);
-=09=09dma_unmap_sg(priv->dev, dst, sreq->nr_dst, DMA_FROM_DEVICE);
+=09=09if (sreq->nr_src > 0)
+=09=09=09dma_unmap_sg(priv->dev, src, sreq->nr_src,
+=09=09=09=09     DMA_TO_DEVICE);
+=09=09if (sreq->nr_dst > 0)
+=09=09=09dma_unmap_sg(priv->dev, dst, sreq->nr_dst,
+=09=09=09=09     DMA_FROM_DEVICE);
 =09}
=20
 =09/*
@@ -737,23 +743,29 @@ static int safexcel_send_req(struct crypto_async_requ=
est *base, int ring,
 =09=09=09=09max(totlen_src, totlen_dst));
 =09=09=09return -EINVAL;
 =09=09}
-=09=09dma_map_sg(priv->dev, src, sreq->nr_src, DMA_BIDIRECTIONAL);
+=09=09if (sreq->nr_src > 0)
+=09=09=09dma_map_sg(priv->dev, src, sreq->nr_src,
+=09=09=09=09   DMA_BIDIRECTIONAL);
 =09} else {
 =09=09if (unlikely(totlen_src && (sreq->nr_src <=3D 0))) {
 =09=09=09dev_err(priv->dev, "Source buffer not large enough (need %d bytes=
)!",
 =09=09=09=09totlen_src);
 =09=09=09return -EINVAL;
 =09=09}
-=09=09dma_map_sg(priv->dev, src, sreq->nr_src, DMA_TO_DEVICE);
+
+=09=09if (sreq->nr_src > 0)
+=09=09=09dma_map_sg(priv->dev, src, sreq->nr_src, DMA_TO_DEVICE);
=20
 =09=09if (unlikely(totlen_dst && (sreq->nr_dst <=3D 0))) {
 =09=09=09dev_err(priv->dev, "Dest buffer not large enough (need %d bytes)!=
",
 =09=09=09=09totlen_dst);
-=09=09=09dma_unmap_sg(priv->dev, src, sreq->nr_src,
-=09=09=09=09     DMA_TO_DEVICE);
-=09=09=09return -EINVAL;
+=09=09=09ret =3D -EINVAL;
+=09=09=09goto unmap;
 =09=09}
-=09=09dma_map_sg(priv->dev, dst, sreq->nr_dst, DMA_FROM_DEVICE);
+
+=09=09if (sreq->nr_dst > 0)
+=09=09=09dma_map_sg(priv->dev, dst, sreq->nr_dst,
+=09=09=09=09   DMA_FROM_DEVICE);
 =09}
=20
 =09memcpy(ctx->base.ctxr->data, ctx->key, ctx->key_len);
@@ -883,12 +895,18 @@ static int safexcel_send_req(struct crypto_async_requ=
est *base, int ring,
 cdesc_rollback:
 =09for (i =3D 0; i < n_cdesc; i++)
 =09=09safexcel_ring_rollback_wptr(priv, &priv->ring[ring].cdr);
-
+unmap:
 =09if (src =3D=3D dst) {
-=09=09dma_unmap_sg(priv->dev, src, sreq->nr_src, DMA_BIDIRECTIONAL);
+=09=09if (sreq->nr_src > 0)
+=09=09=09dma_unmap_sg(priv->dev, src, sreq->nr_src,
+=09=09=09=09     DMA_BIDIRECTIONAL);
 =09} else {
-=09=09dma_unmap_sg(priv->dev, src, sreq->nr_src, DMA_TO_DEVICE);
-=09=09dma_unmap_sg(priv->dev, dst, sreq->nr_dst, DMA_FROM_DEVICE);
+=09=09if (sreq->nr_src > 0)
+=09=09=09dma_unmap_sg(priv->dev, src, sreq->nr_src,
+=09=09=09=09     DMA_TO_DEVICE);
+=09=09if (sreq->nr_dst > 0)
+=09=09=09dma_unmap_sg(priv->dev, dst, sreq->nr_dst,
+=09=09=09=09     DMA_FROM_DEVICE);
 =09}
=20
 =09return ret;
--=20
2.17.1