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authorRussell King <rmk+kernel@arm.linux.org.uk>2014-03-23 22:27:17 +0000
committerRussell King <rmk+kernel@arm.linux.org.uk>2014-10-17 14:35:11 +0100
commit9d498e576d9caa2240a2c85d1b664da046c94d08 (patch)
treef113b12f4f1e3be6ac7d147359665f5611758f1c
parenta29dc07047c66ae31354b3953e136356b2f92cf5 (diff)
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 <rmk+kernel@arm.linux.org.uk>
-rw-r--r--drivers/net/ethernet/freescale/fec_main.c20
1 files 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);