net: wan/fsl_ucc_hdlc: Fix dma_free_coherent() in uhdlc_memclean()

[ Upstream commit 36bd7d5 ]

The priv->rx_buffer and priv->tx_buffer are alloc'd together as
contiguous buffers in uhdlc_init() but freed as two buffers in
uhdlc_memclean().

Change the cleanup to only call dma_free_coherent() once on the whole
buffer.

Reviewed-by: Christophe Leroy (CS GROUP) <chleroy@kernel.org>
Fixes: c19b6d2 ("drivers/net: support hdlc function for QE-UCC")
Cc: <stable@vger.kernel.org>
Signed-off-by: Thomas Fourier <fourier.thomas@gmail.com>
Link: https://patch.msgid.link/20260206085334.21195-2-fourier.thomas@gmail.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

Author: Thomas-fourier

drivers/net/wan/fsl_ucc_hdlc.c

@@ -790,18 +790,14 @@ static void uhdlc_memclean(struct ucc_hdlc_private *priv)
 
 	if (priv->rx_buffer) {
 		dma_free_coherent(priv->dev,
-				  RX_BD_RING_LEN * MAX_RX_BUF_LENGTH,
+				  (RX_BD_RING_LEN + TX_BD_RING_LEN) * MAX_RX_BUF_LENGTH,
 				  priv->rx_buffer, priv->dma_rx_addr);
 		priv->rx_buffer = NULL;
 		priv->dma_rx_addr = 0;
-	}
 
-	if (priv->tx_buffer) {
-		dma_free_coherent(priv->dev,
-				  TX_BD_RING_LEN * MAX_RX_BUF_LENGTH,
-				  priv->tx_buffer, priv->dma_tx_addr);
 		priv->tx_buffer = NULL;
 		priv->dma_tx_addr = 0;
+
 	}
 }