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Commit af4d045c authored by Daniel Borkmann's avatar Daniel Borkmann Committed by David S. Miller
Browse files

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: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarAlexei Starovoitov <ast@kernel.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent e4a8e817

kernel/bpf/devmap.c

+41 −59
Original line number Diff line number Diff line
@@ -48,30 +48,30 @@ 
 * calls will fail at this point.

 */

#include <linux/bpf.h>

#include <linux/jhash.h>

#include <linux/filter.h>

#include <linux/rculist_nulls.h>

#include "percpu_freelist.h"

#include "bpf_lru_list.h"

#include "map_in_map.h"



struct bpf_dtab_netdev {

	struct net_device *dev;

	int key;

	struct rcu_head rcu;

	struct bpf_dtab *dtab;

	unsigned int bit;

	struct rcu_head rcu;

};



struct bpf_dtab {

	struct bpf_map map;

	struct bpf_dtab_netdev **netdev_map;

	unsigned long int __percpu *flush_needed;

	unsigned long __percpu *flush_needed;

	struct list_head list;

};



static DEFINE_SPINLOCK(dev_map_lock);

static LIST_HEAD(dev_map_list);



static u64 dev_map_bitmap_size(const union bpf_attr *attr)

{

	return BITS_TO_LONGS(attr->max_entries) * sizeof(unsigned long);

}



static struct bpf_map *dev_map_alloc(union bpf_attr *attr)

{

	struct bpf_dtab *dtab;
@@ -95,11 +95,9 @@ static struct bpf_map *dev_map_alloc(union bpf_attr *attr) 
	dtab->map.map_flags = attr->map_flags;

	dtab->map.numa_node = bpf_map_attr_numa_node(attr);



	err = -ENOMEM;



	/* 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);

	cost += dev_map_bitmap_size(attr) * num_possible_cpus();

	if (cost >= U32_MAX - PAGE_SIZE)

		goto free_dtab;
@@ -110,11 +108,8 @@ static struct bpf_map *dev_map_alloc(union bpf_attr *attr) 
	if (err)

		goto free_dtab;



	err = -ENOMEM;

	/* 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),

	dtab->flush_needed = __alloc_percpu(dev_map_bitmap_size(attr),

					    __alignof__(unsigned long));

	if (!dtab->flush_needed)

		goto free_dtab;
@@ -128,12 +123,12 @@ static struct bpf_map *dev_map_alloc(union bpf_attr *attr) 
	spin_lock(&dev_map_lock);

	list_add_tail_rcu(&dtab->list, &dev_map_list);

	spin_unlock(&dev_map_lock);

	return &dtab->map;



	return &dtab->map;

free_dtab:

	free_percpu(dtab->flush_needed);

	kfree(dtab);

	return ERR_PTR(err);

	return ERR_PTR(-ENOMEM);

}



static void dev_map_free(struct bpf_map *map)
@@ -178,9 +173,6 @@ static void dev_map_free(struct bpf_map *map) 
		kfree(dev);

	}



	/* 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);
@@ -190,7 +182,7 @@ static int dev_map_get_next_key(struct bpf_map *map, void *key, void *next_key) 
{

	struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map);

	u32 index = key ? *(u32 *)key : U32_MAX;

	u32 *next = (u32 *)next_key;

	u32 *next = next_key;



	if (index >= dtab->map.max_entries) {

		*next = 0;
@@ -199,29 +191,16 @@ static int dev_map_get_next_key(struct bpf_map *map, void *key, void *next_key) 


	if (index == dtab->map.max_entries - 1)

		return -ENOENT;



	*next = index + 1;

	return 0;

}



void __dev_map_insert_ctx(struct bpf_map *map, u32 key)

void __dev_map_insert_ctx(struct bpf_map *map, u32 bit)

{

	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);

	struct bpf_dtab_netdev *dev;



	if (key >= map->max_entries)

		return NULL;



	dev = READ_ONCE(dtab->netdev_map[key]);

	return dev ? dev->dev : NULL;

	__set_bit(bit, bitmap);

}



/* __dev_map_flush is called from xdp_do_flush_map() which _must_ be signaled
@@ -248,7 +227,6 @@ void __dev_map_flush(struct bpf_map *map) 
			continue;



		netdev = dev->dev;



		__clear_bit(bit, bitmap);

		if (unlikely(!netdev || !netdev->netdev_ops->ndo_xdp_flush))

			continue;
@@ -261,43 +239,49 @@ void __dev_map_flush(struct bpf_map *map) 
 * update happens in parallel here a dev_put wont happen until after reading the

 * ifindex.

 */

static void *dev_map_lookup_elem(struct bpf_map *map, void *key)

struct net_device  *__dev_map_lookup_elem(struct bpf_map *map, u32 key)

{

	struct bpf_dtab *dtab = container_of(map, struct bpf_dtab, map);

	struct bpf_dtab_netdev *dev;

	u32 i = *(u32 *)key;



	if (i >= map->max_entries)

	if (key >= map->max_entries)

		return NULL;



	dev = READ_ONCE(dtab->netdev_map[i]);

	return dev ? &dev->dev->ifindex : NULL;

	dev = READ_ONCE(dtab->netdev_map[key]);

	return dev ? dev->dev : NULL;

}



static void dev_map_flush_old(struct bpf_dtab_netdev *old_dev)

static void *dev_map_lookup_elem(struct bpf_map *map, void *key)

{

	if (old_dev->dev->netdev_ops->ndo_xdp_flush) {

		struct net_device *fl = old_dev->dev;

	struct net_device *dev = __dev_map_lookup_elem(map, *(u32 *)key);



	return dev ? &dev->ifindex : NULL;

}



static void dev_map_flush_old(struct bpf_dtab_netdev *dev)

{

	if (dev->dev->netdev_ops->ndo_xdp_flush) {

		struct net_device *fl = 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);

			bitmap = per_cpu_ptr(dev->dtab->flush_needed, cpu);

			__clear_bit(dev->bit, bitmap);



			fl->netdev_ops->ndo_xdp_flush(old_dev->dev);

			fl->netdev_ops->ndo_xdp_flush(dev->dev);

		}

	}

}



static void __dev_map_entry_free(struct rcu_head *rcu)

{

	struct bpf_dtab_netdev *old_dev;

	struct bpf_dtab_netdev *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);

	dev = container_of(rcu, struct bpf_dtab_netdev, rcu);

	dev_map_flush_old(dev);

	dev_put(dev->dev);

	kfree(dev);

}



static int dev_map_delete_elem(struct bpf_map *map, void *key)
@@ -309,8 +293,8 @@ static int dev_map_delete_elem(struct bpf_map *map, void *key) 
	if (k >= map->max_entries)

		return -EINVAL;



	/* Use synchronize_rcu() here to ensure any rcu critical sections

	 * have completed, but this does not guarantee a flush has happened

	/* Use call_rcu() here to ensure any rcu critical sections have

	 * completed, but this does not guarantee a flush has happened

	 * yet. Because driver side rcu_read_lock/unlock only protects the

	 * running XDP program. However, for pending flush operations the

	 * dev and ctx are stored in another per cpu map. And additionally,
@@ -334,10 +318,8 @@ static int dev_map_update_elem(struct bpf_map *map, void *key, void *value, 


	if (unlikely(map_flags > BPF_EXIST))

		return -EINVAL;



	if (unlikely(i >= dtab->map.max_entries))

		return -E2BIG;



	if (unlikely(map_flags == BPF_NOEXIST))

		return -EEXIST;
@@ -355,7 +337,7 @@ static int dev_map_update_elem(struct bpf_map *map, void *key, void *value, 
			return -EINVAL;

		}



		dev->key = i;

		dev->bit = i;

		dev->dtab = dtab;

	}