[PATCH v2] crypto: atmel-tdes - use scatterlist length before DMA mapping

[PATCH v2] crypto: atmel-tdes - use scatterlist length before DMA mapping

[Thorsten Blum]

Using sg_dma_len() is only valid after mapping the scatterlist with
dma_map_sg(). However, atmel_tdes_crypt_start() uses it before mapping
to compare input/output lengths and to compute the transfer count.

Use the original scatterlist lengths before DMA mapping to avoid reading
stale or uninitialized DMA lengths when CONFIG_NEED_SG_DMA_LENGTH=y.

Drop the output scatterlist length in the fast path since it is equal to
->in_sg->length and does not change the transfer count.

Fixes: 13802005d8f2 ("crypto: atmel - add Atmel DES/TDES driver")
Fixes: 1f858040c2f7 ("crypto: atmel-tdes - add support for latest release of the IP (0x700)")
Cc: stable@vger.kernel.org
Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
---
Changes in v2:
- Drop ->out_sg->length in the fast path (Herbert)
- v1: https://lore.kernel.org/lkml/20260531204115.689052-3-thorsten.blum@linux.dev/
---
 drivers/crypto/atmel-tdes.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/crypto/atmel-tdes.c b/drivers/crypto/atmel-tdes.c
index 643e507f9c02..d380f6741a2c 100644
--- a/drivers/crypto/atmel-tdes.c
+++ b/drivers/crypto/atmel-tdes.c
@@ -463,14 +463,13 @@ static int atmel_tdes_crypt_start(struct atmel_tdes_dev *dd)
 			IS_ALIGNED(dd->out_sg->length, dd->ctx->block_size);
 		fast = in && out;
 
-		if (sg_dma_len(dd->in_sg) != sg_dma_len(dd->out_sg))
+		if (dd->in_sg->length != dd->out_sg->length)
 			fast = 0;
 	}
 
 
 	if (fast)  {
-		count = min_t(size_t, dd->total, sg_dma_len(dd->in_sg));
-		count = min_t(size_t, count, sg_dma_len(dd->out_sg));
+		count = min_t(size_t, dd->total, dd->in_sg->length);
 
 		err = dma_map_sg(dd->dev, dd->in_sg, 1, DMA_TO_DEVICE);
 		if (!err) {