This is a note to let you know that I've just added the patch titled
ibmvnic: add memory barrier to protect long term buffer
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
ibmvnic-add-memory-barrier-to-protect-long-term-buff.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit a04450263bf9b18d9fa61622ae535b9084b9a285
Author: Lijun Pan <ljp@xxxxxxxxxxxxx>
Date: Fri Feb 12 20:48:40 2021 -0600
ibmvnic: add memory barrier to protect long term buffer
[ Upstream commit 42557dab78edc8235aba5b441f2eb35f725a0ede ]
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: 032c5e82847a ("Driver for IBM System i/p VNIC protocol")
Signed-off-by: Lijun Pan <ljp@xxxxxxxxxxxxx>
Acked-by: Thomas Falcon <tlfalcon@xxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
index 5b5d488c2f374..901883a44a320 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -1518,6 +1518,9 @@ 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;
@@ -2340,6 +2343,8 @@ 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);
