bpf: minor cleanups for dev_map
Some minor code cleanups, while going over it I also noticed that we're accounting the bitmap only for one CPU currently, so fix that up as well. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Daniel Borkmann
David S. Miller
Родитель
e4a8e817d3
Коммит
af4d045cee
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@ -48,30 +48,30 @@
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* calls will fail at this point.
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*/
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#include <linux/bpf.h>
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#include <linux/jhash.h>
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#include <linux/filter.h>
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#include <linux/rculist_nulls.h>
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#include "percpu_freelist.h"
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#include "bpf_lru_list.h"
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#include "map_in_map.h"
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struct bpf_dtab_netdev {
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struct net_device *dev;
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int key;
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struct rcu_head rcu;
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struct bpf_dtab *dtab;
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unsigned int bit;
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struct rcu_head rcu;
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};
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struct bpf_dtab {
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struct bpf_map map;
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struct bpf_dtab_netdev **netdev_map;
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unsigned long int __percpu *flush_needed;
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unsigned long __percpu *flush_needed;
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struct list_head list;
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};
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static DEFINE_SPINLOCK(dev_map_lock);
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static LIST_HEAD(dev_map_list);
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static u64 dev_map_bitmap_size(const union bpf_attr *attr)
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{
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return BITS_TO_LONGS(attr->max_entries) * sizeof(unsigned long);
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}
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static struct bpf_map *dev_map_alloc(union bpf_attr *attr)
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{
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struct bpf_dtab *dtab;
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@ -95,11 +95,9 @@ static struct bpf_map *dev_map_alloc(union bpf_attr *attr)
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dtab->map.map_flags = attr->map_flags;
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dtab->map.numa_node = bpf_map_attr_numa_node(attr);
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err = -ENOMEM;
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/* make sure page count doesn't overflow */
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cost = (u64) dtab->map.max_entries * sizeof(struct bpf_dtab_netdev *);
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cost += BITS_TO_LONGS(attr->max_entries) * sizeof(unsigned long);
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cost += dev_map_bitmap_size(attr) * num_possible_cpus();
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if (cost >= U32_MAX - PAGE_SIZE)
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goto free_dtab;
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@ -110,12 +108,9 @@ static struct bpf_map *dev_map_alloc(union bpf_attr *attr)
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if (err)
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goto free_dtab;
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err = -ENOMEM;
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/* A per cpu bitfield with a bit per possible net device */
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dtab->flush_needed = __alloc_percpu(
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BITS_TO_LONGS(attr->max_entries) *
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sizeof(unsigned long),
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__alignof__(unsigned long));
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dtab->flush_needed = __alloc_percpu(dev_map_bitmap_size(attr),
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__alignof__(unsigned long));
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if (!dtab->flush_needed)
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goto free_dtab;
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@ -128,12 +123,12 @@ static struct bpf_map *dev_map_alloc(union bpf_attr *attr)
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spin_lock(&dev_map_lock);
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list_add_tail_rcu(&dtab->list, &dev_map_list);
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spin_unlock(&dev_map_lock);
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return &dtab->map;
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return &dtab->map;
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free_dtab:
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free_percpu(dtab->flush_needed);
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kfree(dtab);
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return ERR_PTR(err);
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return ERR_PTR(-ENOMEM);
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}
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static void dev_map_free(struct bpf_map *map)
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@ -178,9 +173,6 @@ static void dev_map_free(struct bpf_map *map)
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kfree(dev);
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}
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/* At this point bpf program is detached and all pending operations
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* _must_ be complete
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*/
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free_percpu(dtab->flush_needed);
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bpf_map_area_free(dtab->netdev_map);
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kfree(dtab);
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@ -190,7 +182,7 @@ static int dev_map_get_next_key(struct bpf_map *map, void *key, void *next_key)
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{
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struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map);
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u32 index = key ? *(u32 *)key : U32_MAX;
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u32 *next = (u32 *)next_key;
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u32 *next = next_key;
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if (index >= dtab->map.max_entries) {
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*next = 0;
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@ -199,29 +191,16 @@ static int dev_map_get_next_key(struct bpf_map *map, void *key, void *next_key)
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if (index == dtab->map.max_entries - 1)
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return -ENOENT;
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*next = index + 1;
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return 0;
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}
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void __dev_map_insert_ctx(struct bpf_map *map, u32 key)
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void __dev_map_insert_ctx(struct bpf_map *map, u32 bit)
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{
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struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map);
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unsigned long *bitmap = this_cpu_ptr(dtab->flush_needed);
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__set_bit(key, bitmap);
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}
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struct net_device *__dev_map_lookup_elem(struct bpf_map *map, u32 key)
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{
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struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map);
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struct bpf_dtab_netdev *dev;
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if (key >= map->max_entries)
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return NULL;
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dev = READ_ONCE(dtab->netdev_map[key]);
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return dev ? dev->dev : NULL;
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__set_bit(bit, bitmap);
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}
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/* __dev_map_flush is called from xdp_do_flush_map() which _must_ be signaled
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@ -248,7 +227,6 @@ void __dev_map_flush(struct bpf_map *map)
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continue;
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netdev = dev->dev;
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__clear_bit(bit, bitmap);
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if (unlikely(!netdev || !netdev->netdev_ops->ndo_xdp_flush))
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continue;
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@ -261,43 +239,49 @@ void __dev_map_flush(struct bpf_map *map)
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* update happens in parallel here a dev_put wont happen until after reading the
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* ifindex.
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*/
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static void *dev_map_lookup_elem(struct bpf_map *map, void *key)
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struct net_device *__dev_map_lookup_elem(struct bpf_map *map, u32 key)
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{
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struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map);
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struct bpf_dtab_netdev *dev;
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u32 i = *(u32 *)key;
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if (i >= map->max_entries)
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if (key >= map->max_entries)
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return NULL;
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dev = READ_ONCE(dtab->netdev_map[i]);
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return dev ? &dev->dev->ifindex : NULL;
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dev = READ_ONCE(dtab->netdev_map[key]);
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return dev ? dev->dev : NULL;
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}
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static void dev_map_flush_old(struct bpf_dtab_netdev *old_dev)
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static void *dev_map_lookup_elem(struct bpf_map *map, void *key)
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{
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if (old_dev->dev->netdev_ops->ndo_xdp_flush) {
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struct net_device *fl = old_dev->dev;
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struct net_device *dev = __dev_map_lookup_elem(map, *(u32 *)key);
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return dev ? &dev->ifindex : NULL;
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}
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static void dev_map_flush_old(struct bpf_dtab_netdev *dev)
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{
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if (dev->dev->netdev_ops->ndo_xdp_flush) {
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struct net_device *fl = dev->dev;
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unsigned long *bitmap;
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int cpu;
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for_each_online_cpu(cpu) {
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bitmap = per_cpu_ptr(old_dev->dtab->flush_needed, cpu);
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__clear_bit(old_dev->key, bitmap);
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bitmap = per_cpu_ptr(dev->dtab->flush_needed, cpu);
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__clear_bit(dev->bit, bitmap);
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fl->netdev_ops->ndo_xdp_flush(old_dev->dev);
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fl->netdev_ops->ndo_xdp_flush(dev->dev);
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}
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}
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}
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static void __dev_map_entry_free(struct rcu_head *rcu)
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{
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struct bpf_dtab_netdev *old_dev;
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struct bpf_dtab_netdev *dev;
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old_dev = container_of(rcu, struct bpf_dtab_netdev, rcu);
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dev_map_flush_old(old_dev);
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dev_put(old_dev->dev);
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kfree(old_dev);
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dev = container_of(rcu, struct bpf_dtab_netdev, rcu);
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dev_map_flush_old(dev);
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dev_put(dev->dev);
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kfree(dev);
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}
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static int dev_map_delete_elem(struct bpf_map *map, void *key)
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@ -309,8 +293,8 @@ static int dev_map_delete_elem(struct bpf_map *map, void *key)
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if (k >= map->max_entries)
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return -EINVAL;
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/* Use synchronize_rcu() here to ensure any rcu critical sections
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* have completed, but this does not guarantee a flush has happened
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/* Use call_rcu() here to ensure any rcu critical sections have
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* completed, but this does not guarantee a flush has happened
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* yet. Because driver side rcu_read_lock/unlock only protects the
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* running XDP program. However, for pending flush operations the
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* dev and ctx are stored in another per cpu map. And additionally,
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@ -334,10 +318,8 @@ static int dev_map_update_elem(struct bpf_map *map, void *key, void *value,
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if (unlikely(map_flags > BPF_EXIST))
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return -EINVAL;
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if (unlikely(i >= dtab->map.max_entries))
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return -E2BIG;
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if (unlikely(map_flags == BPF_NOEXIST))
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return -EEXIST;
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@ -355,7 +337,7 @@ static int dev_map_update_elem(struct bpf_map *map, void *key, void *value,
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return -EINVAL;
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}
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dev->key = i;
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dev->bit = i;
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dev->dtab = dtab;
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}
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