From a3da8adcb54adf027661c704220ead5116b4ed8a Mon Sep 17 00:00:00 2001 From: Julia Cartwright Date: Tue, 5 Dec 2017 18:02:48 -0600 Subject: [PATCH 1/3] net: macb: kill useless use of list_empty() The list_for_each_entry() macro already handles the case where the list is empty (by not executing the loop body). It's not necessary to handle this case specially, so stop doing so. Cc: Rafal Ozieblo Acked-by: Nicolas Ferre Signed-off-by: Julia Cartwright Signed-off-by: David S. Miller --- drivers/net/ethernet/cadence/macb_main.c | 31 +++++++++--------------- 1 file changed, 12 insertions(+), 19 deletions(-) diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c index ebfeab853bf4..b7644836aba1 100644 --- a/drivers/net/ethernet/cadence/macb_main.c +++ b/drivers/net/ethernet/cadence/macb_main.c @@ -2812,24 +2812,20 @@ static int gem_add_flow_filter(struct net_device *netdev, htons(fs->h_u.tcp_ip4_spec.psrc), htons(fs->h_u.tcp_ip4_spec.pdst)); /* find correct place to add in list */ - if (list_empty(&bp->rx_fs_list.list)) - list_add(&newfs->list, &bp->rx_fs_list.list); - else { - list_for_each_entry(item, &bp->rx_fs_list.list, list) { - if (item->fs.location > newfs->fs.location) { - list_add_tail(&newfs->list, &item->list); - added = true; - break; - } else if (item->fs.location == fs->location) { - netdev_err(netdev, "Rule not added: location %d not free!\n", - fs->location); - ret = -EBUSY; - goto err; - } + list_for_each_entry(item, &bp->rx_fs_list.list, list) { + if (item->fs.location > newfs->fs.location) { + list_add_tail(&newfs->list, &item->list); + added = true; + break; + } else if (item->fs.location == fs->location) { + netdev_err(netdev, "Rule not added: location %d not free!\n", + fs->location); + ret = -EBUSY; + goto err; } - if (!added) - list_add_tail(&newfs->list, &bp->rx_fs_list.list); } + if (!added) + list_add_tail(&newfs->list, &bp->rx_fs_list.list); gem_prog_cmp_regs(bp, fs); bp->rx_fs_list.count++; @@ -2851,9 +2847,6 @@ static int gem_del_flow_filter(struct net_device *netdev, struct ethtool_rx_fs_item *item; struct ethtool_rx_flow_spec *fs; - if (list_empty(&bp->rx_fs_list.list)) - return -EINVAL; - list_for_each_entry(item, &bp->rx_fs_list.list, list) { if (item->fs.location == cmd->fs.location) { /* disable screener regs for the flow entry */ From 7038cdb7d6d0e0b9294171ec7a6417aa48914165 Mon Sep 17 00:00:00 2001 From: Julia Cartwright Date: Tue, 5 Dec 2017 18:02:49 -0600 Subject: [PATCH 2/3] net: macb: reduce scope of rx_fs_lock-protected regions Commit ae8223de3df5 ("net: macb: Added support for RX filtering") introduces a lock, rx_fs_lock which is intended to protect the list of rx_flow items and synchronize access to the hardware rx filtering registers. However, the region protected by this lock is overscoped, unnecessarily including things like slab allocation. Reduce this lock scope to only include operations which must be performed atomically: list traversal, addition, and removal, and hitting the macb filtering registers. This fixes the use of kmalloc w/ GFP_KERNEL in atomic context. Fixes: ae8223de3df5 ("net: macb: Added support for RX filtering") Cc: Rafal Ozieblo Cc: Julia Lawall Acked-by: Nicolas Ferre Signed-off-by: Julia Cartwright Signed-off-by: David S. Miller --- drivers/net/ethernet/cadence/macb_main.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c index b7644836aba1..758e8b3042b2 100644 --- a/drivers/net/ethernet/cadence/macb_main.c +++ b/drivers/net/ethernet/cadence/macb_main.c @@ -2796,6 +2796,7 @@ static int gem_add_flow_filter(struct net_device *netdev, struct macb *bp = netdev_priv(netdev); struct ethtool_rx_flow_spec *fs = &cmd->fs; struct ethtool_rx_fs_item *item, *newfs; + unsigned long flags; int ret = -EINVAL; bool added = false; @@ -2811,6 +2812,8 @@ static int gem_add_flow_filter(struct net_device *netdev, htonl(fs->h_u.tcp_ip4_spec.ip4dst), htons(fs->h_u.tcp_ip4_spec.psrc), htons(fs->h_u.tcp_ip4_spec.pdst)); + spin_lock_irqsave(&bp->rx_fs_lock, flags); + /* find correct place to add in list */ list_for_each_entry(item, &bp->rx_fs_list.list, list) { if (item->fs.location > newfs->fs.location) { @@ -2833,9 +2836,11 @@ static int gem_add_flow_filter(struct net_device *netdev, if (netdev->features & NETIF_F_NTUPLE) gem_enable_flow_filters(bp, 1); + spin_unlock_irqrestore(&bp->rx_fs_lock, flags); return 0; err: + spin_unlock_irqrestore(&bp->rx_fs_lock, flags); kfree(newfs); return ret; } @@ -2846,6 +2851,9 @@ static int gem_del_flow_filter(struct net_device *netdev, struct macb *bp = netdev_priv(netdev); struct ethtool_rx_fs_item *item; struct ethtool_rx_flow_spec *fs; + unsigned long flags; + + spin_lock_irqsave(&bp->rx_fs_lock, flags); list_for_each_entry(item, &bp->rx_fs_list.list, list) { if (item->fs.location == cmd->fs.location) { @@ -2862,12 +2870,14 @@ static int gem_del_flow_filter(struct net_device *netdev, gem_writel_n(bp, SCRT2, fs->location, 0); list_del(&item->list); - kfree(item); bp->rx_fs_list.count--; + spin_unlock_irqrestore(&bp->rx_fs_lock, flags); + kfree(item); return 0; } } + spin_unlock_irqrestore(&bp->rx_fs_lock, flags); return -EINVAL; } @@ -2936,11 +2946,8 @@ static int gem_get_rxnfc(struct net_device *netdev, struct ethtool_rxnfc *cmd, static int gem_set_rxnfc(struct net_device *netdev, struct ethtool_rxnfc *cmd) { struct macb *bp = netdev_priv(netdev); - unsigned long flags; int ret; - spin_lock_irqsave(&bp->rx_fs_lock, flags); - switch (cmd->cmd) { case ETHTOOL_SRXCLSRLINS: if ((cmd->fs.location >= bp->max_tuples) @@ -2959,7 +2966,6 @@ static int gem_set_rxnfc(struct net_device *netdev, struct ethtool_rxnfc *cmd) ret = -EOPNOTSUPP; } - spin_unlock_irqrestore(&bp->rx_fs_lock, flags); return ret; } From cc1674eeee60ad158d16129837bd91f93a2f7b26 Mon Sep 17 00:00:00 2001 From: Julia Cartwright Date: Tue, 5 Dec 2017 18:02:50 -0600 Subject: [PATCH 3/3] net: macb: change GFP_ATOMIC to GFP_KERNEL Now that the rx_fs_lock is no longer held across allocation, it's safe to use GFP_KERNEL for allocating new entries. This reverts commit 81da3bf6e3f88 ("net: macb: change GFP_KERNEL to GFP_ATOMIC"). Cc: Julia Lawall Signed-off-by: Julia Cartwright Signed-off-by: David S. Miller --- drivers/net/ethernet/cadence/macb_main.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c index 758e8b3042b2..234667eaaa92 100644 --- a/drivers/net/ethernet/cadence/macb_main.c +++ b/drivers/net/ethernet/cadence/macb_main.c @@ -2800,7 +2800,7 @@ static int gem_add_flow_filter(struct net_device *netdev, int ret = -EINVAL; bool added = false; - newfs = kmalloc(sizeof(*newfs), GFP_ATOMIC); + newfs = kmalloc(sizeof(*newfs), GFP_KERNEL); if (newfs == NULL) return -ENOMEM; memcpy(&newfs->fs, fs, sizeof(newfs->fs));