Commit 42557dab authored by Lijun Pan's avatar Lijun Pan Committed by David S. Miller
Browse files

ibmvnic: add memory barrier to protect long term buffer 



dma_rmb() barrier is added to load the long term buffer before copying
it to socket buffer; and dma_wmb() barrier is added to update the
long term buffer before it being accessed by VIOS (virtual i/o server).

Fixes: 032c5e82 ("Driver for IBM System i/p VNIC protocol")
Signed-off-by: default avatarLijun Pan <ljp@linux.ibm.com>
Acked-by: default avatarThomas Falcon <tlfalcon@linux.ibm.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 7ce189fa

drivers/net/ethernet/ibm/ibmvnic.c

+5 −0
Original line number Diff line number Diff line
@@ -1700,6 +1700,9 @@ static netdev_tx_t ibmvnic_xmit(struct sk_buff *skb, struct net_device *netdev) 
		skb_copy_from_linear_data(skb, dst, skb->len);

	}



	/* post changes to long_term_buff *dst before VIOS accessing it */

	dma_wmb();



	tx_pool->consumer_index =

	    (tx_pool->consumer_index + 1) % tx_pool->num_buffers;
@@ -2539,6 +2542,8 @@ static int ibmvnic_poll(struct napi_struct *napi, int budget) 
		offset = be16_to_cpu(next->rx_comp.off_frame_data);

		flags = next->rx_comp.flags;

		skb = rx_buff->skb;

		/* load long_term_buff before copying to skb */

		dma_rmb();

		skb_copy_to_linear_data(skb, rx_buff->data + offset,

					length);