From 9d498e576d9caa2240a2c85d1b664da046c94d08 Mon Sep 17 00:00:00 2001 From: Russell King Date: Sun, 23 Mar 2014 22:27:17 +0000 Subject: net: fec: add barrier to receive path to ensure proper ordering Just as we need a barrier in the transmit path, we also need a barrier in the receive path to ensure that we don't modify a handed over descriptor. Signed-off-by: Russell King --- drivers/net/ethernet/freescale/fec_main.c | 20 +++++++++++++------- 1 file changed, 13 insertions(+), 7 deletions(-) diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c index 5c75217169f8..27ef27f6994f 100644 --- a/drivers/net/ethernet/freescale/fec_main.c +++ b/drivers/net/ethernet/freescale/fec_main.c @@ -1377,13 +1377,6 @@ fec_enet_rx(struct net_device *ndev, int budget) dma_sync_single_for_device(&fep->pdev->dev, bdp->cbd_bufaddr, FEC_ENET_RX_FRSIZE, DMA_FROM_DEVICE); rx_processing_done: - /* Clear the status flags for this buffer */ - status &= ~BD_ENET_RX_STATS; - - /* Mark the buffer empty */ - status |= BD_ENET_RX_EMPTY; - bdp->cbd_sc = status; - if (fep->bufdesc_ex) { struct bufdesc_ex *ebdp = (struct bufdesc_ex *)bdp; @@ -1392,6 +1385,19 @@ rx_processing_done: ebdp->cbd_bdu = 0; } + /* + * Ensure that the previous writes have completed before + * the status update becomes visible. + */ + wmb(); + + /* Clear the status flags for this buffer */ + status &= ~BD_ENET_RX_STATS; + + /* Mark the buffer empty */ + status |= BD_ENET_RX_EMPTY; + bdp->cbd_sc = status; + /* Update BD pointer to next entry */ bdp = fec_enet_get_nextdesc(bdp, fep); -- cgit