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Commit 5449e271 authored by Lendacky, Thomas's avatar Lendacky, Thomas Committed by David S. Miller
Browse files

amd-xgbe: Add a read memory barrier to Tx/Rx path 



Add a read memory barrier to the Tx and Rx paths where the ownership
bit is checked to be sure that all descriptor fields are read after
having read the ownership bit for the descriptor.

This has not been an issue to date, but it's a good safe-guard to have.

Signed-off-by: default avatarTom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 91ecee68

drivers/net/ethernet/amd/xgbe/xgbe-dev.c

+3 −0
Original line number Diff line number Diff line
@@ -1558,6 +1558,9 @@ static int xgbe_dev_read(struct xgbe_channel *channel) 
	if (XGMAC_GET_BITS_LE(rdesc->desc3, RX_NORMAL_DESC3, OWN))

		return 1;



	/* Make sure descriptor fields are read after reading the OWN bit */

	rmb();



#ifdef XGMAC_ENABLE_RX_DESC_DUMP

	xgbe_dump_rx_desc(ring, rdesc, ring->cur);

#endif

drivers/net/ethernet/amd/xgbe/xgbe-drv.c

+4 −0
Original line number Diff line number Diff line
@@ -1791,6 +1791,10 @@ static int xgbe_tx_poll(struct xgbe_channel *channel) 
		if (!hw_if->tx_complete(rdesc))

			break;



		/* Make sure descriptor fields are read after reading the OWN

		 * bit */

		rmb();



#ifdef XGMAC_ENABLE_TX_DESC_DUMP

		xgbe_dump_tx_desc(ring, ring->dirty, 1, 0);

#endif