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vmxnet3: use DMA memory barriers where required

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[ Upstream commit f3002c1374 ]

The gen bits must be read first from (resp. written last to) DMA memory.
The proper way to enforce this on Linux is to call dma_rmb() (resp.
dma_wmb()).

Signed-off-by: Regis Duchesne <hpreg@vmware.com>
Acked-by: Ronak Doshi <doshir@vmware.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
hpreg@vmware.com 2018-05-14 08:14:49 -04:00 committed by Greg Kroah-Hartman
parent 779fd38b60
commit aab3292261
1 changed files with 22 additions and 0 deletions
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22
drivers/net/vmxnet3/vmxnet3_drv.c
View file

@ -369,6 +369,11 @@ vmxnet3_tq_tx_complete(struct vmxnet3_tx_queue *tq,
gdesc = tq->comp_ring.base + tq->comp_ring.next2proc;
while (VMXNET3_TCD_GET_GEN(&gdesc->tcd) == tq->comp_ring.gen) {
/* Prevent any &gdesc->tcd field from being (speculatively)
* read before (&gdesc->tcd)->gen is read.
*/
dma_rmb();
completed += vmxnet3_unmap_pkt(VMXNET3_TCD_GET_TXIDX(
&gdesc->tcd), tq, adapter->pdev,
adapter);
@ -1099,6 +1104,11 @@ vmxnet3_tq_xmit(struct sk_buff *skb, struct vmxnet3_tx_queue *tq,
gdesc->txd.tci = skb_vlan_tag_get(skb);
}
/* Ensure that the write to (&gdesc->txd)->gen will be observed after
* all other writes to &gdesc->txd.
*/
dma_wmb();
/* finally flips the GEN bit of the SOP desc. */
gdesc->dword[2] = cpu_to_le32(le32_to_cpu(gdesc->dword[2]) ^
VMXNET3_TXD_GEN);
@ -1286,6 +1296,12 @@ vmxnet3_rq_rx_complete(struct vmxnet3_rx_queue *rq,
*/
break;
}
/* Prevent any rcd field from being (speculatively) read before
* rcd->gen is read.
*/
dma_rmb();
BUG_ON(rcd->rqID != rq->qid && rcd->rqID != rq->qid2 &&
rcd->rqID != rq->dataRingQid);
idx = rcd->rxdIdx;
@ -1515,6 +1531,12 @@ vmxnet3_rq_rx_complete(struct vmxnet3_rx_queue *rq,
ring->next2comp = idx;
num_to_alloc = vmxnet3_cmd_ring_desc_avail(ring);
ring = rq->rx_ring + ring_idx;
/* Ensure that the writes to rxd->gen bits will be observed
* after all other writes to rxd objects.
*/
dma_wmb();
while (num_to_alloc) {
vmxnet3_getRxDesc(rxd, &ring->base[ring->next2fill].rxd,
&rxCmdDesc);