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().
Signed-off-by: Sinan Kaya <okaya@xxxxxxxxxxxxxx>
---
drivers/infiniband/hw/nes/nes.h | 5 +++++
drivers/infiniband/hw/nes/nes_hw.c | 21 ++++++++++++++-------
drivers/infiniband/hw/nes/nes_mgt.c | 15 ++++++++++-----
drivers/infiniband/hw/nes/nes_nic.c | 2 +-
drivers/infiniband/hw/nes/nes_utils.c | 3 ++-
drivers/infiniband/hw/nes/nes_verbs.c | 5 +++--
6 files changed, 35 insertions(+), 16 deletions(-)
diff --git a/drivers/infiniband/hw/nes/nes.h b/drivers/infiniband/hw/nes/nes.h
index 00c27291..85e007d 100644
--- a/drivers/infiniband/hw/nes/nes.h
+++ b/drivers/infiniband/hw/nes/nes.h
@@ -387,6 +387,11 @@ static inline void nes_write_indexed(struct nes_device *nesdev, u32 reg_index, u
spin_unlock_irqrestore(&nesdev->indexed_regs_lock, flags);
}
+static inline void nes_write32_relaxed(void __iomem *addr, u32 val)
+{
+ writel_relaxed(val, addr);
+}
+
static inline void nes_write32(void __iomem *addr, u32 val)
{
writel(val, addr);
diff --git a/drivers/infiniband/hw/nes/nes_hw.c b/drivers/infiniband/hw/nes/nes_hw.c
index 18a7de1..568e17d 100644
--- a/drivers/infiniband/hw/nes/nes_hw.c
+++ b/drivers/infiniband/hw/nes/nes_hw.c
@@ -1257,7 +1257,8 @@ int nes_destroy_cqp(struct nes_device *nesdev)
barrier();
/* Ring doorbell (5 WQEs) */
- nes_write32(nesdev->regs+NES_WQE_ALLOC, 0x05800000 | nesdev->cqp.qp_id);
+ nes_write32_relaxed(nesdev->regs+NES_WQE_ALLOC,
+ 0x05800000 | nesdev->cqp.qp_id);
spin_unlock_irqrestore(&nesdev->cqp.lock, flags);
@@ -1594,7 +1595,8 @@ static void nes_replenish_nic_rq(struct nes_vnic *nesvnic)
atomic_dec(&nesvnic->rx_skbs_needed);
barrier();
if (++rx_wqes_posted == 255) {
- nes_write32(nesdev->regs+NES_WQE_ALLOC, (rx_wqes_posted << 24) | nesnic->qp_id);
+ nes_write32_relaxed(nesdev->regs+NES_WQE_ALLOC,
+ (rx_wqes_posted << 24) | nesnic->qp_id);
rx_wqes_posted = 0;
}
} else {
@@ -1612,7 +1614,8 @@ static void nes_replenish_nic_rq(struct nes_vnic *nesvnic)
} while (atomic_read(&nesvnic->rx_skbs_needed));
barrier();
if (rx_wqes_posted)
- nes_write32(nesdev->regs+NES_WQE_ALLOC, (rx_wqes_posted << 24) | nesnic->qp_id);
+ nes_write32_relaxed(nesdev->regs+NES_WQE_ALLOC,
+ (rx_wqes_posted << 24) | nesnic->qp_id);
nesnic->replenishing_rq = 0;
}
@@ -1795,7 +1798,8 @@ int nes_init_nic_qp(struct nes_device *nesdev, struct net_device *netdev)
barrier();
/* Ring doorbell (2 WQEs) */
- nes_write32(nesdev->regs+NES_WQE_ALLOC, 0x02800000 | nesdev->cqp.qp_id);
+ nes_write32_relaxed(nesdev->regs+NES_WQE_ALLOC,
+ 0x02800000 | nesdev->cqp.qp_id);
spin_unlock_irqrestore(&nesdev->cqp.lock, flags);
nes_debug(NES_DBG_INIT, "Waiting for create NIC QP%u to complete.\n",
@@ -1844,7 +1848,8 @@ int nes_init_nic_qp(struct nes_device *nesdev, struct net_device *netdev)
do {
counter = min(wqe_count, ((u32)255));
wqe_count -= counter;
- nes_write32(nesdev->regs+NES_WQE_ALLOC, (counter << 24) | nesvnic->nic.qp_id);
+ nes_write32_relaxed(nesdev->regs+NES_WQE_ALLOC,
+ (counter << 24) | nesvnic->nic.qp_id);
} while (wqe_count);
timer_setup(&nesvnic->rq_wqes_timer, nes_rq_wqes_timeout, 0);
nes_debug(NES_DBG_INIT, "NAPI support Enabled\n");
@@ -1988,7 +1993,8 @@ void nes_destroy_nic_qp(struct nes_vnic *nesvnic)
barrier();
/* Ring doorbell (2 WQEs) */
- nes_write32(nesdev->regs+NES_WQE_ALLOC, 0x02800000 | nesdev->cqp.qp_id);
+ nes_write32_relaxed(nesdev->regs+NES_WQE_ALLOC,
+ 0x02800000 | nesdev->cqp.qp_id);
spin_unlock_irqrestore(&nesdev->cqp.lock, flags);
nes_debug(NES_DBG_SHUTDOWN, "Waiting for CQP, cqp_head=%u, cqp.sq_head=%u,"
@@ -3064,7 +3070,8 @@ static void nes_cqp_ce_handler(struct nes_device *nesdev, struct nes_hw_cq *cq)
cqp_request, le32_to_cpu(cqp_wqe->wqe_words[NES_CQP_WQE_OPCODE_IDX])&0x3f, head);
/* Ring doorbell (1 WQEs) */
barrier();
- nes_write32(nesdev->regs+NES_WQE_ALLOC, 0x01800000 | nesdev->cqp.qp_id);
+ nes_write32_relaxed(nesdev->regs+NES_WQE_ALLOC,
+ 0x01800000 | nesdev->cqp.qp_id);
}
spin_unlock_irqrestore(&nesdev->cqp.lock, flags);
diff --git a/drivers/infiniband/hw/nes/nes_mgt.c b/drivers/infiniband/hw/nes/nes_mgt.c
index 21e0ebd..5c5073c 100644
--- a/drivers/infiniband/hw/nes/nes_mgt.c
+++ b/drivers/infiniband/hw/nes/nes_mgt.c
@@ -96,7 +96,8 @@ static void nes_replenish_mgt_rq(struct nes_vnic_mgt *mgtvnic)
atomic_dec(&mgtvnic->rx_skbs_needed);
barrier();
if (++rx_wqes_posted == 255) {
- nes_write32(nesdev->regs + NES_WQE_ALLOC, (rx_wqes_posted << 24) | nesmgt->qp_id);
+ nes_write32_relaxed(nesdev->regs + NES_WQE_ALLOC,
+ (rx_wqes_posted << 24) | nesmgt->qp_id);
rx_wqes_posted = 0;
}
} else {
@@ -115,7 +116,8 @@ static void nes_replenish_mgt_rq(struct nes_vnic_mgt *mgtvnic)
} while (atomic_read(&mgtvnic->rx_skbs_needed));
barrier();
if (rx_wqes_posted)
- nes_write32(nesdev->regs + NES_WQE_ALLOC, (rx_wqes_posted << 24) | nesmgt->qp_id);
+ nes_write32_relaxed(nesdev->regs + NES_WQE_ALLOC,
+ (rx_wqes_posted << 24) | nesmgt->qp_id);
nesmgt->replenishing_rq = 0;
}
@@ -995,7 +997,8 @@ int nes_init_mgt_qp(struct nes_device *nesdev, struct net_device *netdev, struct
barrier();
/* Ring doorbell (2 WQEs) */
- nes_write32(nesdev->regs + NES_WQE_ALLOC, 0x02800000 | nesdev->cqp.qp_id);
+ nes_write32_relaxed(nesdev->regs + NES_WQE_ALLOC,
+ 0x02800000 | nesdev->cqp.qp_id);
spin_unlock_irqrestore(&nesdev->cqp.lock, flags);
nes_debug(NES_DBG_INIT, "Waiting for create MGT QP%u to complete.\n",
@@ -1050,7 +1053,8 @@ int nes_init_mgt_qp(struct nes_device *nesdev, struct net_device *netdev, struct
do {
counter = min(wqe_count, ((u32)255));
wqe_count -= counter;
- nes_write32(nesdev->regs + NES_WQE_ALLOC, (counter << 24) | mgtvnic->mgt.qp_id);
+ nes_write32_relaxed(nesdev->regs + NES_WQE_ALLOC,
+ (counter << 24) | mgtvnic->mgt.qp_id);
} while (wqe_count);
nes_write32(nesdev->regs + NES_CQE_ALLOC, NES_CQE_ALLOC_NOTIFY_NEXT |
@@ -1124,7 +1128,8 @@ void nes_destroy_mgt(struct nes_vnic *nesvnic)
barrier();
/* Ring doorbell (2 WQEs) */
- nes_write32(nesdev->regs + NES_WQE_ALLOC, 0x02800000 | nesdev->cqp.qp_id);
+ nes_write32_relaxed(nesdev->regs + NES_WQE_ALLOC,
+ 0x02800000 | nesdev->cqp.qp_id);
spin_unlock_irqrestore(&nesdev->cqp.lock, flags);
nes_debug(NES_DBG_SHUTDOWN, "Waiting for CQP, cqp_head=%u, cqp.sq_head=%u,"
diff --git a/drivers/infiniband/hw/nes/nes_nic.c b/drivers/infiniband/hw/nes/nes_nic.c
index 0a75164..0653da0 100644
--- a/drivers/infiniband/hw/nes/nes_nic.c
+++ b/drivers/infiniband/hw/nes/nes_nic.c
@@ -683,7 +683,7 @@ static int nes_netdev_start_xmit(struct sk_buff *skb, struct net_device *netdev)
barrier();
if (wqe_count)
- nes_write32(nesdev->regs+NES_WQE_ALLOC,
+ nes_write32_relaxed(nesdev->regs+NES_WQE_ALLOC,
(wqe_count << 24) | (1 << 23) | nesvnic->nic.qp_id);
netif_trans_update(netdev);
diff --git a/drivers/infiniband/hw/nes/nes_utils.c b/drivers/infiniband/hw/nes/nes_utils.c
index 21b4a83..79a3d98 100644
--- a/drivers/infiniband/hw/nes/nes_utils.c
+++ b/drivers/infiniband/hw/nes/nes_utils.c
@@ -661,7 +661,8 @@ void nes_post_cqp_request(struct nes_device *nesdev,
barrier();
/* Ring doorbell (1 WQEs) */
- nes_write32(nesdev->regs+NES_WQE_ALLOC, 0x01800000 | nesdev->cqp.qp_id);
+ nes_write32_relaxed(nesdev->regs+NES_WQE_ALLOC,
+ 0x01800000 | nesdev->cqp.qp_id);
barrier();
} else {
diff --git a/drivers/infiniband/hw/nes/nes_verbs.c b/drivers/infiniband/hw/nes/nes_verbs.c
index 162475a..87f8635 100644
--- a/drivers/infiniband/hw/nes/nes_verbs.c
+++ b/drivers/infiniband/hw/nes/nes_verbs.c
@@ -3310,7 +3310,7 @@ static int nes_post_send(struct ib_qp *ibqp, struct ib_send_wr *ib_wr,
while (wqe_count) {
counter = min(wqe_count, ((u32)255));
wqe_count -= counter;
- nes_write32(nesdev->regs + NES_WQE_ALLOC,
+ nes_write32_relaxed(nesdev->regs + NES_WQE_ALLOC,
(counter << 24) | 0x00800000 | nesqp->hwqp.qp_id);
}
@@ -3404,7 +3404,8 @@ static int nes_post_recv(struct ib_qp *ibqp, struct ib_recv_wr *ib_wr,
while (wqe_count) {
counter = min(wqe_count, ((u32)255));
wqe_count -= counter;
- nes_write32(nesdev->regs+NES_WQE_ALLOC, (counter<<24) | nesqp->hwqp.qp_id);
+ nes_write32_relaxed(nesdev->regs+NES_WQE_ALLOC,
+ (counter<<24) | nesqp->hwqp.qp_id);
}
spin_unlock_irqrestore(&nesqp->lock, flags);
--
2.7.4
--
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