diff options
| author |   Sinan Kaya <okaya@codeaurora.org> | 2018-03-25 10:39:21 -0400 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2018-03-26 12:47:56 -0400 |
| commit | 6d2e1a8d5e25e5f4563f5ea24bcb5da1ae261b26 (patch) | |
| tree | dd2b5acaa6a1c2a12456ffc5aa546f707f1a91ee /drivers/net/ethernet/amazon/ena/ena_netdev.c | |
| parent | bnxt_en: Eliminate duplicate barriers on weakly-ordered archs (diff) | |
| download | linux-dev-6d2e1a8d5e25e5f4563f5ea24bcb5da1ae261b26.tar.xz linux-dev-6d2e1a8d5e25e5f4563f5ea24bcb5da1ae261b26.zip | |
net: ena: Eliminate duplicate barriers on weakly-ordered archs
Code includes barrier() followed by writel(). writel() already has a
barrier on some architectures like arm64.
This ends up CPU observing two barriers back to back before executing the
register write.
Create a new wrapper function with relaxed write operator. Use the new
wrapper when a write is following a barrier().
Since code already has an explicit barrier call, changing writel() to
writel_relaxed() and adding mmiowb() for ordering protection.
Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to '')
| -rw-r--r-- | drivers/net/ethernet/amazon/ena/ena_netdev.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/drivers/net/ethernet/amazon/ena/ena_netdev.c b/drivers/net/ethernet/amazon/ena/ena_netdev.c index 6975150d144e..a822e70c2af3 100644 --- a/drivers/net/ethernet/amazon/ena/ena_netdev.c +++ b/drivers/net/ethernet/amazon/ena/ena_netdev.c @@ -556,7 +556,8 @@ static int ena_refill_rx_bufs(struct ena_ring *rx_ring, u32 num) * issue a doorbell */ wmb(); - ena_com_write_sq_doorbell(rx_ring->ena_com_io_sq); + ena_com_write_sq_doorbell(rx_ring->ena_com_io_sq, true); + mmiowb(); } rx_ring->next_to_use = next_to_use; @@ -2151,7 +2152,7 @@ static netdev_tx_t ena_start_xmit(struct sk_buff *skb, struct net_device *dev) if (netif_xmit_stopped(txq) || !skb->xmit_more) { /* trigger the dma engine */ - ena_com_write_sq_doorbell(tx_ring->ena_com_io_sq); + ena_com_write_sq_doorbell(tx_ring->ena_com_io_sq, false); u64_stats_update_begin(&tx_ring->syncp); tx_ring->tx_stats.doorbells++; u64_stats_update_end(&tx_ring->syncp); |