[PATCH v7 3/7] bnx2x: Replace doorbell barrier() with wmb()

Sinan Kaya
2018-03-25T14:39:47Z

barrier() doesn't guarantee memory writes to be observed by the hardware on
all architectures. barrier() only tells compiler not to move this code
with respect to other read/writes.

If memory write needs to be observed by the HW, wmb() is the right choice.

Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
---
drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c | 3 ++-
drivers/net/ethernet/broadcom/bnx2x/bnx2x_ethtool.c | 3 ++-
2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
index d7c98e8..0f86f18 100644
--- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
+++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
@@ -4153,7 +4153,8 @@ netdev_tx_t bnx2x_start_xmit(struct sk_buff *skb, struct net_device *dev)
wmb();

txdata->tx_db.data.prod += nbd;
- barrier();
+ /* make sure descriptor update is observed by HW */
+ wmb();

DOORBELL(bp, txdata->cid, txdata->tx_db.raw);

diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_ethtool.c b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_ethtool.c
index 1e33abd..39af4f8 100644
--- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_ethtool.c
+++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_ethtool.c
@@ -2591,7 +2591,8 @@ static int bnx2x_run_loopback(struct bnx2x *bp, int loopback_mode)
wmb();

txdata->tx_db.data.prod += 2;
- barrier();
+ /* make sure descriptor update is observed by the HW */
+ wmb();
DOORBELL(bp, txdata->cid, txdata->tx_db.raw);

mmiowb();
--
2.7.4