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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 1/2] crypto: inside_secure - Avoid dma map if size is zero
Date:   Mon, 5 Sep 2022 12:14:43 +0800
Message-ID: <b08e76c7ff0e46e25e21ee0827fcf3b0e94556bf.1662351087.git.pliem@maxlinear.com>
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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>
---
 drivers/crypto/inside-secure/safexcel_cipher.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/crypto/inside-secure/safexcel_cipher.c b/drivers/crypt=
o/inside-secure/safexcel_cipher.c
index d68ef16650d4..3775497775e0 100644
--- a/drivers/crypto/inside-secure/safexcel_cipher.c
+++ b/drivers/crypto/inside-secure/safexcel_cipher.c
@@ -737,14 +737,17 @@ 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, 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)!=
",
@@ -753,7 +756,9 @@ static int safexcel_send_req(struct crypto_async_reques=
t *base, int ring,
 =09=09=09=09     DMA_TO_DEVICE);
 =09=09=09return -EINVAL;
 =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, DMA_FROM_DEVICE);
 =09}
=20
 =09memcpy(ctx->base.ctxr->data, ctx->key, ctx->key_len);
--=20
2.17.1