diff options
| -rw-r--r-- | drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 28 | ||||
| -rw-r--r-- | include/linux/bpf.h | 2 | ||||
| -rw-r--r-- | include/linux/filter.h | 7 | ||||
| -rw-r--r-- | include/linux/netdevice.h | 5 | ||||
| -rw-r--r-- | kernel/bpf/devmap.c | 84 | ||||
| -rw-r--r-- | net/core/filter.c | 55 |
6 files changed, 166 insertions, 15 deletions
diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c index 38f7ff9..0f867dc 100644 --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c @@ -2415,6 +2415,8 @@ static int ixgbe_clean_rx_irq(struct ixgbe_q_vector *q_vector, */ wmb(); writel(ring->next_to_use, ring->tail); + + xdp_do_flush_map(); } u64_stats_update_begin(&rx_ring->syncp); @@ -5817,6 +5819,9 @@ void ixgbe_down(struct ixgbe_adapter *adapter) usleep_range(10000, 20000); + /* synchronize_sched() needed for pending XDP buffers to drain */ + if (adapter->xdp_ring[0]) + synchronize_sched(); netif_tx_stop_all_queues(netdev); /* call carrier off first to avoid false dev_watchdog timeouts */ @@ -9850,15 +9855,31 @@ static int ixgbe_xdp_xmit(struct net_device *dev, struct xdp_buff *xdp) if (err != IXGBE_XDP_TX) return -ENOMEM; + return 0; +} + +static void ixgbe_xdp_flush(struct net_device *dev) +{ + struct ixgbe_adapter *adapter = netdev_priv(dev); + struct ixgbe_ring *ring; + + /* Its possible the device went down between xdp xmit and flush so + * we need to ensure device is still up. + */ + if (unlikely(test_bit(__IXGBE_DOWN, &adapter->state))) + return; + + ring = adapter->xdp_prog ? adapter->xdp_ring[smp_processor_id()] : NULL; + if (unlikely(!ring)) + return; + /* Force memory writes to complete before letting h/w know there * are new descriptors to fetch. */ wmb(); - - ring = adapter->xdp_ring[smp_processor_id()]; writel(ring->next_to_use, ring->tail); - return 0; + return; } static const struct net_device_ops ixgbe_netdev_ops = { @@ -9908,6 +9929,7 @@ static const struct net_device_ops ixgbe_netdev_ops = { .ndo_features_check = ixgbe_features_check, .ndo_xdp = ixgbe_xdp, .ndo_xdp_xmit = ixgbe_xdp_xmit, + .ndo_xdp_flush = ixgbe_xdp_flush, }; /** diff --git a/include/linux/bpf.h b/include/linux/bpf.h index d0d3281..6850a76 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -381,5 +381,7 @@ u64 bpf_user_rnd_u32(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5); /* Map specifics */ struct net_device *__dev_map_lookup_elem(struct bpf_map *map, u32 key); +void __dev_map_insert_ctx(struct bpf_map *map, u32 index); +void __dev_map_flush(struct bpf_map *map); #endif /* _LINUX_BPF_H */ diff --git a/include/linux/filter.h b/include/linux/filter.h index ce8211f..3323ee9 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -712,10 +712,17 @@ bool bpf_helper_changes_pkt_data(void *func); struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off, const struct bpf_insn *patch, u32 len); +/* The pair of xdp_do_redirect and xdp_do_flush_map MUST be called in the + * same cpu context. Further for best results no more than a single map + * for the do_redirect/do_flush pair should be used. This limitation is + * because we only track one map and force a flush when the map changes. + * This does not appear to be a real limiation for existing software. + */ int xdp_do_generic_redirect(struct net_device *dev, struct sk_buff *skb); int xdp_do_redirect(struct net_device *dev, struct xdp_buff *xdp, struct bpf_prog *prog); +void xdp_do_flush_map(void); void bpf_warn_invalid_xdp_action(u32 act); void bpf_warn_invalid_xdp_redirect(u32 ifindex); diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 77f5376..03b1049 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -1142,7 +1142,9 @@ struct xfrmdev_ops { * int (*ndo_xdp_xmit)(struct net_device *dev, struct xdp_buff *xdp); * This function is used to submit a XDP packet for transmit on a * netdevice. - * + * void (*ndo_xdp_flush)(struct net_device *dev); + * This function is used to inform the driver to flush a paticular + * xpd tx queue. Must be called on same CPU as xdp_xmit. */ struct net_device_ops { int (*ndo_init)(struct net_device *dev); @@ -1329,6 +1331,7 @@ struct net_device_ops { struct netdev_xdp *xdp); int (*ndo_xdp_xmit)(struct net_device *dev, struct xdp_buff *xdp); + void (*ndo_xdp_flush)(struct net_device *dev); }; /** diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c index 36dc13de..b2ef04a 100644 --- a/kernel/bpf/devmap.c +++ b/kernel/bpf/devmap.c @@ -53,6 +53,7 @@ struct bpf_dtab_netdev { struct bpf_dtab { struct bpf_map map; struct bpf_dtab_netdev **netdev_map; + unsigned long int __percpu *flush_needed; }; static struct bpf_map *dev_map_alloc(union bpf_attr *attr) @@ -87,6 +88,7 @@ static struct bpf_map *dev_map_alloc(union bpf_attr *attr) /* make sure page count doesn't overflow */ cost = (u64) dtab->map.max_entries * sizeof(struct bpf_dtab_netdev *); + cost += BITS_TO_LONGS(attr->max_entries) * sizeof(unsigned long); if (cost >= U32_MAX - PAGE_SIZE) goto free_dtab; @@ -97,6 +99,14 @@ static struct bpf_map *dev_map_alloc(union bpf_attr *attr) if (err) goto free_dtab; + /* A per cpu bitfield with a bit per possible net device */ + dtab->flush_needed = __alloc_percpu( + BITS_TO_LONGS(attr->max_entries) * + sizeof(unsigned long), + __alignof__(unsigned long)); + if (!dtab->flush_needed) + goto free_dtab; + dtab->netdev_map = bpf_map_area_alloc(dtab->map.max_entries * sizeof(struct bpf_dtab_netdev *)); if (!dtab->netdev_map) @@ -105,6 +115,7 @@ static struct bpf_map *dev_map_alloc(union bpf_attr *attr) return &dtab->map; free_dtab: + free_percpu(dtab->flush_needed); kfree(dtab); return ERR_PTR(err); } @@ -112,7 +123,7 @@ free_dtab: static void dev_map_free(struct bpf_map *map) { struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map); - int i; + int i, cpu; /* At this point bpf_prog->aux->refcnt == 0 and this map->refcnt == 0, * so the programs (can be more than one that used this map) were @@ -123,6 +134,18 @@ static void dev_map_free(struct bpf_map *map) */ synchronize_rcu(); + /* To ensure all pending flush operations have completed wait for flush + * bitmap to indicate all flush_needed bits to be zero on _all_ cpus. + * Because the above synchronize_rcu() ensures the map is disconnected + * from the program we can assume no new bits will be set. + */ + for_each_online_cpu(cpu) { + unsigned long *bitmap = per_cpu_ptr(dtab->flush_needed, cpu); + + while (!bitmap_empty(bitmap, dtab->map.max_entries)) + cpu_relax(); + } + for (i = 0; i < dtab->map.max_entries; i++) { struct bpf_dtab_netdev *dev; @@ -137,6 +160,7 @@ static void dev_map_free(struct bpf_map *map) /* At this point bpf program is detached and all pending operations * _must_ be complete */ + free_percpu(dtab->flush_needed); bpf_map_area_free(dtab->netdev_map); kfree(dtab); } @@ -159,6 +183,14 @@ static int dev_map_get_next_key(struct bpf_map *map, void *key, void *next_key) return 0; } +void __dev_map_insert_ctx(struct bpf_map *map, u32 key) +{ + struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map); + unsigned long *bitmap = this_cpu_ptr(dtab->flush_needed); + + __set_bit(key, bitmap); +} + struct net_device *__dev_map_lookup_elem(struct bpf_map *map, u32 key) { struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map); @@ -171,6 +203,39 @@ struct net_device *__dev_map_lookup_elem(struct bpf_map *map, u32 key) return dev ? dev->dev : NULL; } +/* __dev_map_flush is called from xdp_do_flush_map() which _must_ be signaled + * from the driver before returning from its napi->poll() routine. The poll() + * routine is called either from busy_poll context or net_rx_action signaled + * from NET_RX_SOFTIRQ. Either way the poll routine must complete before the + * net device can be torn down. On devmap tear down we ensure the ctx bitmap + * is zeroed before completing to ensure all flush operations have completed. + */ +void __dev_map_flush(struct bpf_map *map) +{ + struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map); + unsigned long *bitmap = this_cpu_ptr(dtab->flush_needed); + u32 bit; + + for_each_set_bit(bit, bitmap, map->max_entries) { + struct bpf_dtab_netdev *dev = READ_ONCE(dtab->netdev_map[bit]); + struct net_device *netdev; + + /* This is possible if the dev entry is removed by user space + * between xdp redirect and flush op. + */ + if (unlikely(!dev)) + continue; + + netdev = dev->dev; + + __clear_bit(bit, bitmap); + if (unlikely(!netdev || !netdev->netdev_ops->ndo_xdp_flush)) + continue; + + netdev->netdev_ops->ndo_xdp_flush(netdev); + } +} + /* rcu_read_lock (from syscall and BPF contexts) ensures that if a delete and/or * update happens in parallel here a dev_put wont happen until after reading the * ifindex. @@ -188,11 +253,28 @@ static void *dev_map_lookup_elem(struct bpf_map *map, void *key) return dev ? &dev->dev->ifindex : NULL; } +static void dev_map_flush_old(struct bpf_dtab_netdev *old_dev) +{ + if (old_dev->dev->netdev_ops->ndo_xdp_flush) { + struct net_device *fl = old_dev->dev; + unsigned long *bitmap; + int cpu; + + for_each_online_cpu(cpu) { + bitmap = per_cpu_ptr(old_dev->dtab->flush_needed, cpu); + __clear_bit(old_dev->key, bitmap); + + fl->netdev_ops->ndo_xdp_flush(old_dev->dev); + } + } +} + static void __dev_map_entry_free(struct rcu_head *rcu) { struct bpf_dtab_netdev *old_dev; old_dev = container_of(rcu, struct bpf_dtab_netdev, rcu); + dev_map_flush_old(old_dev); dev_put(old_dev->dev); kfree(old_dev); } diff --git a/net/core/filter.c b/net/core/filter.c index e93a558..e23aa6f 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -1780,6 +1780,7 @@ struct redirect_info { u32 ifindex; u32 flags; struct bpf_map *map; + struct bpf_map *map_to_flush; }; static DEFINE_PER_CPU(struct redirect_info, redirect_info); @@ -2438,34 +2439,68 @@ static const struct bpf_func_proto bpf_xdp_adjust_head_proto = { .arg2_type = ARG_ANYTHING, }; -static int __bpf_tx_xdp(struct net_device *dev, struct xdp_buff *xdp) +static int __bpf_tx_xdp(struct net_device *dev, + struct bpf_map *map, + struct xdp_buff *xdp, + u32 index) { - if (dev->netdev_ops->ndo_xdp_xmit) { - dev->netdev_ops->ndo_xdp_xmit(dev, xdp); - return 0; + int err; + + if (!dev->netdev_ops->ndo_xdp_xmit) { + bpf_warn_invalid_xdp_redirect(dev->ifindex); + return -EOPNOTSUPP; } - bpf_warn_invalid_xdp_redirect(dev->ifindex); - return -EOPNOTSUPP; + + err = dev->netdev_ops->ndo_xdp_xmit(dev, xdp); + if (err) + return err; + + if (map) + __dev_map_insert_ctx(map, index); + else + dev->netdev_ops->ndo_xdp_flush(dev); + + return err; } +void xdp_do_flush_map(void) +{ + struct redirect_info *ri = this_cpu_ptr(&redirect_info); + struct bpf_map *map = ri->map_to_flush; + + ri->map = NULL; + ri->map_to_flush = NULL; + + if (map) + __dev_map_flush(map); +} +EXPORT_SYMBOL_GPL(xdp_do_flush_map); + int xdp_do_redirect_map(struct net_device *dev, struct xdp_buff *xdp, struct bpf_prog *xdp_prog) { struct redirect_info *ri = this_cpu_ptr(&redirect_info); struct bpf_map *map = ri->map; + u32 index = ri->ifindex; struct net_device *fwd; int err = -EINVAL; ri->ifindex = 0; ri->map = NULL; - fwd = __dev_map_lookup_elem(map, ri->ifindex); + fwd = __dev_map_lookup_elem(map, index); if (!fwd) goto out; - trace_xdp_redirect(dev, fwd, xdp_prog, XDP_REDIRECT); - err = __bpf_tx_xdp(fwd, xdp); + if (ri->map_to_flush && (ri->map_to_flush != map)) + xdp_do_flush_map(); + + err = __bpf_tx_xdp(fwd, map, xdp, index); + if (likely(!err)) + ri->map_to_flush = map; + out: + trace_xdp_redirect(dev, fwd, xdp_prog, XDP_REDIRECT); return err; } @@ -2488,7 +2523,7 @@ int xdp_do_redirect(struct net_device *dev, struct xdp_buff *xdp, trace_xdp_redirect(dev, fwd, xdp_prog, XDP_REDIRECT); - return __bpf_tx_xdp(fwd, xdp); + return __bpf_tx_xdp(fwd, NULL, xdp, 0); } EXPORT_SYMBOL_GPL(xdp_do_redirect); |
