From de3d6fa81e684af5817dc379ffc394235a9666cc Mon Sep 17 00:00:00 2001 From: Tariq Toukan Date: Tue, 20 Sep 2016 14:39:39 +0300 Subject: [PATCH 1/4] net/mlx4_en: Add branch prediction hints in RX data-path Add likely/unlikely hints to improve branch predictions in the RX data-path. Signed-off-by: Tariq Toukan Signed-off-by: David S. Miller --- drivers/net/ethernet/mellanox/mlx4/en_rx.c | 26 ++++++++++++---------- 1 file changed, 14 insertions(+), 12 deletions(-) diff --git a/drivers/net/ethernet/mellanox/mlx4/en_rx.c b/drivers/net/ethernet/mellanox/mlx4/en_rx.c index c46355bce613..6e474af3fb1f 100644 --- a/drivers/net/ethernet/mellanox/mlx4/en_rx.c +++ b/drivers/net/ethernet/mellanox/mlx4/en_rx.c @@ -72,7 +72,7 @@ static int mlx4_alloc_pages(struct mlx4_en_priv *priv, } dma = dma_map_page(priv->ddev, page, 0, PAGE_SIZE << order, frag_info->dma_dir); - if (dma_mapping_error(priv->ddev, dma)) { + if (unlikely(dma_mapping_error(priv->ddev, dma))) { put_page(page); return -ENOMEM; } @@ -108,7 +108,8 @@ static int mlx4_en_alloc_frags(struct mlx4_en_priv *priv, ring_alloc[i].page_size) continue; - if (mlx4_alloc_pages(priv, &page_alloc[i], frag_info, gfp)) + if (unlikely(mlx4_alloc_pages(priv, &page_alloc[i], + frag_info, gfp))) goto out; } @@ -585,7 +586,7 @@ static int mlx4_en_complete_rx_desc(struct mlx4_en_priv *priv, frag_info = &priv->frag_info[nr]; if (length <= frag_info->frag_prefix_size) break; - if (!frags[nr].page) + if (unlikely(!frags[nr].page)) goto fail; dma = be64_to_cpu(rx_desc->data[nr].addr); @@ -625,7 +626,7 @@ static struct sk_buff *mlx4_en_rx_skb(struct mlx4_en_priv *priv, dma_addr_t dma; skb = netdev_alloc_skb(priv->dev, SMALL_PACKET_SIZE + NET_IP_ALIGN); - if (!skb) { + if (unlikely(!skb)) { en_dbg(RX_ERR, priv, "Failed allocating skb\n"); return NULL; } @@ -736,7 +737,8 @@ static int get_fixed_ipv6_csum(__wsum hw_checksum, struct sk_buff *skb, { __wsum csum_pseudo_hdr = 0; - if (ipv6h->nexthdr == IPPROTO_FRAGMENT || ipv6h->nexthdr == IPPROTO_HOPOPTS) + if (unlikely(ipv6h->nexthdr == IPPROTO_FRAGMENT || + ipv6h->nexthdr == IPPROTO_HOPOPTS)) return -1; hw_checksum = csum_add(hw_checksum, (__force __wsum)htons(ipv6h->nexthdr)); @@ -769,7 +771,7 @@ static int check_csum(struct mlx4_cqe *cqe, struct sk_buff *skb, void *va, get_fixed_ipv4_csum(hw_checksum, skb, hdr); #if IS_ENABLED(CONFIG_IPV6) else if (cqe->status & cpu_to_be16(MLX4_CQE_STATUS_IPV6)) - if (get_fixed_ipv6_csum(hw_checksum, skb, hdr)) + if (unlikely(get_fixed_ipv6_csum(hw_checksum, skb, hdr))) return -1; #endif return 0; @@ -796,10 +798,10 @@ int mlx4_en_process_rx_cq(struct net_device *dev, struct mlx4_en_cq *cq, int bud u64 timestamp; bool l2_tunnel; - if (!priv->port_up) + if (unlikely(!priv->port_up)) return 0; - if (budget <= 0) + if (unlikely(budget <= 0)) return polled; /* Protect accesses to: ring->xdp_prog, priv->mac_hash list */ @@ -902,9 +904,9 @@ int mlx4_en_process_rx_cq(struct net_device *dev, struct mlx4_en_cq *cq, int bud case XDP_PASS: break; case XDP_TX: - if (!mlx4_en_xmit_frame(frags, dev, + if (likely(!mlx4_en_xmit_frame(frags, dev, length, tx_index, - &doorbell_pending)) + &doorbell_pending))) goto consumed; goto xdp_drop; /* Drop on xmit failure */ default: @@ -912,7 +914,7 @@ int mlx4_en_process_rx_cq(struct net_device *dev, struct mlx4_en_cq *cq, int bud case XDP_ABORTED: case XDP_DROP: xdp_drop: - if (mlx4_en_rx_recycle(ring, frags)) + if (likely(mlx4_en_rx_recycle(ring, frags))) goto consumed; goto next; } @@ -1016,7 +1018,7 @@ xdp_drop: /* GRO not possible, complete processing here */ skb = mlx4_en_rx_skb(priv, rx_desc, frags, length); - if (!skb) { + if (unlikely(!skb)) { ring->dropped++; goto next; } From 57c970c2e8d8772237294bb8a6a25a205448fd96 Mon Sep 17 00:00:00 2001 From: Kamal Heib Date: Tue, 20 Sep 2016 14:39:40 +0300 Subject: [PATCH 2/4] net/mlx4_en: Fix wrong indentation Use tabs instead of spaces before if statement, no functional change. Fixes: e7c1c2c46201 ("mlx4_en: Added self diagnostics test implementation") Signed-off-by: Kamal Heib Signed-off-by: Tariq Toukan Signed-off-by: David S. Miller --- drivers/net/ethernet/mellanox/mlx4/en_rx.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/ethernet/mellanox/mlx4/en_rx.c b/drivers/net/ethernet/mellanox/mlx4/en_rx.c index 6e474af3fb1f..f2e8beddcf44 100644 --- a/drivers/net/ethernet/mellanox/mlx4/en_rx.c +++ b/drivers/net/ethernet/mellanox/mlx4/en_rx.c @@ -1023,7 +1023,7 @@ xdp_drop: goto next; } - if (unlikely(priv->validate_loopback)) { + if (unlikely(priv->validate_loopback)) { validate_loopback(priv, skb); goto next; } From 30353bfc43a1602c020f31d95cf27182ffd23824 Mon Sep 17 00:00:00 2001 From: Leon Romanovsky Date: Tue, 20 Sep 2016 14:39:41 +0300 Subject: [PATCH 3/4] net/mlx4_core: Use RCU to perform radix tree lookup for SRQ Radix tree lookup can be performed without locking. Fixes: 225c7b1feef1 ("IB/mlx4: Add a driver Mellanox ConnectX InfiniBand adapters") Signed-off-by: Leon Romanovsky Suggested-by: Sagi Grimberg Signed-off-by: Tariq Toukan Signed-off-by: David S. Miller --- drivers/net/ethernet/mellanox/mlx4/srq.c | 14 +++++--------- 1 file changed, 5 insertions(+), 9 deletions(-) diff --git a/drivers/net/ethernet/mellanox/mlx4/srq.c b/drivers/net/ethernet/mellanox/mlx4/srq.c index 67146624eb58..f44d089e2ca6 100644 --- a/drivers/net/ethernet/mellanox/mlx4/srq.c +++ b/drivers/net/ethernet/mellanox/mlx4/srq.c @@ -45,15 +45,12 @@ void mlx4_srq_event(struct mlx4_dev *dev, u32 srqn, int event_type) struct mlx4_srq_table *srq_table = &mlx4_priv(dev)->srq_table; struct mlx4_srq *srq; - spin_lock(&srq_table->lock); - + rcu_read_lock(); srq = radix_tree_lookup(&srq_table->tree, srqn & (dev->caps.num_srqs - 1)); + rcu_read_unlock(); if (srq) atomic_inc(&srq->refcount); - - spin_unlock(&srq_table->lock); - - if (!srq) { + else { mlx4_warn(dev, "Async event for bogus SRQ %08x\n", srqn); return; } @@ -301,12 +298,11 @@ struct mlx4_srq *mlx4_srq_lookup(struct mlx4_dev *dev, u32 srqn) { struct mlx4_srq_table *srq_table = &mlx4_priv(dev)->srq_table; struct mlx4_srq *srq; - unsigned long flags; - spin_lock_irqsave(&srq_table->lock, flags); + rcu_read_lock(); srq = radix_tree_lookup(&srq_table->tree, srqn & (dev->caps.num_srqs - 1)); - spin_unlock_irqrestore(&srq_table->lock, flags); + rcu_read_unlock(); return srq; } From a7e1f04905e5b2b90251974dddde781301b6be37 Mon Sep 17 00:00:00 2001 From: Jack Morgenstein Date: Tue, 20 Sep 2016 14:39:42 +0300 Subject: [PATCH 4/4] net/mlx4_core: Fix deadlock when switching between polling and event fw commands When switching from polling-based fw commands to event-based fw commands, there is a race condition which could cause a fw command in another task to hang: that task will keep waiting for the polling sempahore, but may never be able to acquire it. This is due to mlx4_cmd_use_events, which "down"s the sempahore back to 0. During driver initialization, this is not a problem, since no other tasks which invoke FW commands are active. However, there is a problem if the driver switches to polling mode and then back to event mode during normal operation. The "test_interrupts" feature does exactly that. Running "ethtool -t offline" causes the PF driver to temporarily switch to polling mode, and then back to event mode. (Note that for VF drivers, such switching is not performed). Fix this by adding a read-write semaphore for protection when switching between modes. Fixes: 225c7b1feef1 ("IB/mlx4: Add a driver Mellanox ConnectX InfiniBand adapters") Signed-off-by: Jack Morgenstein Signed-off-by: Matan Barak Signed-off-by: Tariq Toukan Signed-off-by: David S. Miller --- drivers/net/ethernet/mellanox/mlx4/cmd.c | 23 +++++++++++++++++------ drivers/net/ethernet/mellanox/mlx4/mlx4.h | 2 ++ 2 files changed, 19 insertions(+), 6 deletions(-) diff --git a/drivers/net/ethernet/mellanox/mlx4/cmd.c b/drivers/net/ethernet/mellanox/mlx4/cmd.c index f04a423ff79d..a58d96cf1ed1 100644 --- a/drivers/net/ethernet/mellanox/mlx4/cmd.c +++ b/drivers/net/ethernet/mellanox/mlx4/cmd.c @@ -785,17 +785,23 @@ int __mlx4_cmd(struct mlx4_dev *dev, u64 in_param, u64 *out_param, return mlx4_cmd_reset_flow(dev, op, op_modifier, -EIO); if (!mlx4_is_mfunc(dev) || (native && mlx4_is_master(dev))) { + int ret; + if (dev->persist->state & MLX4_DEVICE_STATE_INTERNAL_ERROR) return mlx4_internal_err_ret_value(dev, op, op_modifier); + down_read(&mlx4_priv(dev)->cmd.switch_sem); if (mlx4_priv(dev)->cmd.use_events) - return mlx4_cmd_wait(dev, in_param, out_param, - out_is_imm, in_modifier, - op_modifier, op, timeout); + ret = mlx4_cmd_wait(dev, in_param, out_param, + out_is_imm, in_modifier, + op_modifier, op, timeout); else - return mlx4_cmd_poll(dev, in_param, out_param, - out_is_imm, in_modifier, - op_modifier, op, timeout); + ret = mlx4_cmd_poll(dev, in_param, out_param, + out_is_imm, in_modifier, + op_modifier, op, timeout); + + up_read(&mlx4_priv(dev)->cmd.switch_sem); + return ret; } return mlx4_slave_cmd(dev, in_param, out_param, out_is_imm, in_modifier, op_modifier, op, timeout); @@ -2454,6 +2460,7 @@ int mlx4_cmd_init(struct mlx4_dev *dev) int flags = 0; if (!priv->cmd.initialized) { + init_rwsem(&priv->cmd.switch_sem); mutex_init(&priv->cmd.slave_cmd_mutex); sema_init(&priv->cmd.poll_sem, 1); priv->cmd.use_events = 0; @@ -2583,6 +2590,7 @@ int mlx4_cmd_use_events(struct mlx4_dev *dev) if (!priv->cmd.context) return -ENOMEM; + down_write(&priv->cmd.switch_sem); for (i = 0; i < priv->cmd.max_cmds; ++i) { priv->cmd.context[i].token = i; priv->cmd.context[i].next = i + 1; @@ -2606,6 +2614,7 @@ int mlx4_cmd_use_events(struct mlx4_dev *dev) down(&priv->cmd.poll_sem); priv->cmd.use_events = 1; + up_write(&priv->cmd.switch_sem); return err; } @@ -2618,6 +2627,7 @@ void mlx4_cmd_use_polling(struct mlx4_dev *dev) struct mlx4_priv *priv = mlx4_priv(dev); int i; + down_write(&priv->cmd.switch_sem); priv->cmd.use_events = 0; for (i = 0; i < priv->cmd.max_cmds; ++i) @@ -2626,6 +2636,7 @@ void mlx4_cmd_use_polling(struct mlx4_dev *dev) kfree(priv->cmd.context); up(&priv->cmd.poll_sem); + up_write(&priv->cmd.switch_sem); } struct mlx4_cmd_mailbox *mlx4_alloc_cmd_mailbox(struct mlx4_dev *dev) diff --git a/drivers/net/ethernet/mellanox/mlx4/mlx4.h b/drivers/net/ethernet/mellanox/mlx4/mlx4.h index c9d7fc5159f2..c128ba3ef014 100644 --- a/drivers/net/ethernet/mellanox/mlx4/mlx4.h +++ b/drivers/net/ethernet/mellanox/mlx4/mlx4.h @@ -46,6 +46,7 @@ #include #include #include +#include #include #include @@ -627,6 +628,7 @@ struct mlx4_cmd { struct mutex slave_cmd_mutex; struct semaphore poll_sem; struct semaphore event_sem; + struct rw_semaphore switch_sem; int max_cmds; spinlock_t context_lock; int free_head;