diff mbox series

net: octeon: mgmt: Repair filling of RX ring

Message ID 20200529121710.548394-1-alexander.sverdlin@nokia.com
State Accepted
Delegated to: David Miller
Headers show
Series net: octeon: mgmt: Repair filling of RX ring | expand

Commit Message

Alexander A Sverdlin May 29, 2020, 12:17 p.m. UTC 
From: Alexander Sverdlin <alexander.sverdlin@nokia.com>

The removal of mips_swiotlb_ops exposed a problem in octeon_mgmt Ethernet
driver. mips_swiotlb_ops had an mb() after most of the operations and the
removal of the ops had broken the receive functionality of the driver.
My code inspection has shown no other places except
octeon_mgmt_rx_fill_ring() where an explicit barrier would be obviously
missing. The latter function however has to make sure that "ringing the
bell" doesn't happen before RX ring entry is really written.

The patch has been successfully tested on Octeon II.

Fixes: a999933db9ed ("MIPS: remove mips_swiotlb_ops")
Cc: stable@vger.kernel.org
Signed-off-by: Alexander Sverdlin <alexander.sverdlin@nokia.com>
---
 drivers/net/ethernet/cavium/octeon/octeon_mgmt.c | 5 +++++
 1 file changed, 5 insertions(+)
diff mbox series

Patch

diff --git a/drivers/net/ethernet/cavium/octeon/octeon_mgmt.c b/drivers/net/ethernet/cavium/octeon/octeon_mgmt.c
index 07b960e..79c110a 100644
--- a/drivers/net/ethernet/cavium/octeon/octeon_mgmt.c
+++ b/drivers/net/ethernet/cavium/octeon/octeon_mgmt.c
@@ -235,6 +235,11 @@  static void octeon_mgmt_rx_fill_ring(struct net_device *netdev)
 
 		/* Put it in the ring.  */
 		p->rx_ring[p->rx_next_fill] = re.d64;
+		/* Make sure there is no reorder of filling the ring and ringing
+		 * the bell
+		 */
+		wmb();
+
 		dma_sync_single_for_device(p->dev, p->rx_ring_handle,
 					   ring_size_to_bytes(OCTEON_MGMT_RX_RING_SIZE),
 					   DMA_BIDIRECTIONAL);