diff options
| author | Sinan Kaya <okaya@codeaurora.org> | 2018-03-25 17:39:19 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2018-03-26 19:47:56 +0300 |
| commit | e42d8cee343a545ac2d9557a3b28708bbca2bd31 (patch) | |
| tree | b48c9e39d600f5230f4b3e3e7261a59a615f5fa3 /drivers/net/ethernet/qlogic/qlge | |
| parent | 7f883c774e1bad34d5474d8a74989336631ce178 (diff) | |
| download | linux-e42d8cee343a545ac2d9557a3b28708bbca2bd31.tar.xz | |
net: qlge: Eliminate duplicate barriers on weakly-ordered archs
Code includes wmb() 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 wmb().
Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/ethernet/qlogic/qlge')
| -rw-r--r-- | drivers/net/ethernet/qlogic/qlge/qlge.h | 16 | ||||
| -rw-r--r-- | drivers/net/ethernet/qlogic/qlge/qlge_main.c | 3 |
2 files changed, 18 insertions, 1 deletions
diff --git a/drivers/net/ethernet/qlogic/qlge/qlge.h b/drivers/net/ethernet/qlogic/qlge/qlge.h index 84ac50f92c9c..3e71b65a9546 100644 --- a/drivers/net/ethernet/qlogic/qlge/qlge.h +++ b/drivers/net/ethernet/qlogic/qlge/qlge.h @@ -2185,6 +2185,22 @@ static inline void ql_write_db_reg(u32 val, void __iomem *addr) } /* + * Doorbell Registers: + * Doorbell registers are virtual registers in the PCI memory space. + * The space is allocated by the chip during PCI initialization. The + * device driver finds the doorbell address in BAR 3 in PCI config space. + * The registers are used to control outbound and inbound queues. For + * example, the producer index for an outbound queue. Each queue uses + * 1 4k chunk of memory. The lower half of the space is for outbound + * queues. The upper half is for inbound queues. + * Caller has to guarantee ordering. + */ +static inline void ql_write_db_reg_relaxed(u32 val, void __iomem *addr) +{ + writel_relaxed(val, addr); +} + +/* * Shadow Registers: * Outbound queues have a consumer index that is maintained by the chip. * Inbound queues have a producer index that is maintained by the chip. diff --git a/drivers/net/ethernet/qlogic/qlge/qlge_main.c b/drivers/net/ethernet/qlogic/qlge/qlge_main.c index 50038d946ced..8293c2028002 100644 --- a/drivers/net/ethernet/qlogic/qlge/qlge_main.c +++ b/drivers/net/ethernet/qlogic/qlge/qlge_main.c @@ -2700,7 +2700,8 @@ static netdev_tx_t qlge_send(struct sk_buff *skb, struct net_device *ndev) tx_ring->prod_idx = 0; wmb(); - ql_write_db_reg(tx_ring->prod_idx, tx_ring->prod_idx_db_reg); + ql_write_db_reg_relaxed(tx_ring->prod_idx, tx_ring->prod_idx_db_reg); + mmiowb(); netif_printk(qdev, tx_queued, KERN_DEBUG, qdev->ndev, "tx queued, slot %d, len %d\n", tx_ring->prod_idx, skb->len); |