[PATCH net] net: wan: fsl_uhdlc_hdlc: fix dma_rmb usage in hdlc_rx_done

[Holger Brunck <holger.brunck@hitachienergy.com>]

If dma_rmb is used it has to be done after reading bd_status and checking
if R_E_S is zero. Therefore we need to move it into the while loop.

Fixes: c19b6d246a35 ("drivers/net: support hdlc function for QE-UCC")
Signed-off-by: Holger Brunck <holger.brunck@hitachienergy.com>
---
 drivers/net/wan/fsl_ucc_hdlc.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/net/wan/fsl_ucc_hdlc.c b/drivers/net/wan/fsl_ucc_hdlc.c
index 15bfb78381d4..09081f128a98 100644
--- a/drivers/net/wan/fsl_ucc_hdlc.c
+++ b/drivers/net/wan/fsl_ucc_hdlc.c
@@ -523,12 +523,12 @@ static int hdlc_rx_done(struct ucc_hdlc_private *priv, int rx_work_limit)
 	u16 length, howmany = 0;
 	u8 *bdbuffer;
 
-	dma_rmb();
 	bd = priv->currx_bd;
 	bd_status = be16_to_cpu(bd->status);
 
 	/* while there are received buffers and BD is full (~R_E) */
 	while (!((bd_status & (R_E_S)) || (--rx_work_limit < 0))) {
+		dma_rmb();
 		if (bd_status & (RX_BD_ERRORS)) {
 			dev->stats.rx_errors++;
 
@@ -610,7 +610,6 @@ static int hdlc_rx_done(struct ucc_hdlc_private *priv, int rx_work_limit)
 
 		bd_status = be16_to_cpu(bd->status);
 	}
-	dma_rmb();
 
 	priv->currx_bd = bd;
 	return howmany;
-- 
2.47.3