Commit 64fe8c06 authored by Björn Töpel's avatar Björn Töpel Committed by Daniel Borkmann
Browse files

xsk: Store struct xdp_sock as a flexible array member of the XSKMAP 



Prior this commit, the array storing XDP socket instances were stored
in a separate allocated array of the XSKMAP. Now, we store the sockets
as a flexible array member in a similar fashion as the arraymap. Doing
so, we do less pointer chasing in the lookup.

Signed-off-by: default avatarBjörn Töpel <bjorn.topel@intel.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarJonathan Lemon <jonathan.lemon@gmail.com>
Link: https://lore.kernel.org/bpf/20191101110346.15004-2-bjorn.topel@gmail.com
parent 75b0bfd2

kernel/bpf/xskmap.c

+23 −32
Original line number Diff line number Diff line
@@ -11,9 +11,9 @@ 


struct xsk_map {

	struct bpf_map map;

	struct xdp_sock **xsk_map;

	struct list_head __percpu *flush_list;

	spinlock_t lock; /* Synchronize map updates */

	struct xdp_sock *xsk_map[];

};



int xsk_map_inc(struct xsk_map *map)
@@ -80,9 +80,10 @@ static void xsk_map_sock_delete(struct xdp_sock *xs, 


static struct bpf_map *xsk_map_alloc(union bpf_attr *attr)

{

	struct bpf_map_memory mem;

	int cpu, err, numa_node;

	struct xsk_map *m;

	int cpu, err;

	u64 cost;

	u64 cost, size;



	if (!capable(CAP_NET_ADMIN))

		return ERR_PTR(-EPERM);
@@ -92,44 +93,35 @@ static struct bpf_map *xsk_map_alloc(union bpf_attr *attr) 
	    attr->map_flags & ~(BPF_F_NUMA_NODE | BPF_F_RDONLY | BPF_F_WRONLY))

		return ERR_PTR(-EINVAL);



	m = kzalloc(sizeof(*m), GFP_USER);

	if (!m)

	numa_node = bpf_map_attr_numa_node(attr);

	size = struct_size(m, xsk_map, attr->max_entries);

	cost = size + array_size(sizeof(*m->flush_list), num_possible_cpus());



	err = bpf_map_charge_init(&mem, cost);

	if (err < 0)

		return ERR_PTR(err);



	m = bpf_map_area_alloc(size, numa_node);

	if (!m) {

		bpf_map_charge_finish(&mem);

		return ERR_PTR(-ENOMEM);

	}



	bpf_map_init_from_attr(&m->map, attr);

	bpf_map_charge_move(&m->map.memory, &mem);

	spin_lock_init(&m->lock);



	cost = (u64)m->map.max_entries * sizeof(struct xdp_sock *);

	cost += sizeof(struct list_head) * num_possible_cpus();



	/* Notice returns -EPERM on if map size is larger than memlock limit */

	err = bpf_map_charge_init(&m->map.memory, cost);

	if (err)

		goto free_m;



	err = -ENOMEM;



	m->flush_list = alloc_percpu(struct list_head);

	if (!m->flush_list)

		goto free_charge;

	if (!m->flush_list) {

		bpf_map_charge_finish(&m->map.memory);

		bpf_map_area_free(m);

		return ERR_PTR(-ENOMEM);

	}



	for_each_possible_cpu(cpu)

		INIT_LIST_HEAD(per_cpu_ptr(m->flush_list, cpu));



	m->xsk_map = bpf_map_area_alloc(m->map.max_entries *

					sizeof(struct xdp_sock *),

					m->map.numa_node);

	if (!m->xsk_map)

		goto free_percpu;

	return &m->map;



free_percpu:

	free_percpu(m->flush_list);

free_charge:

	bpf_map_charge_finish(&m->map.memory);

free_m:

	kfree(m);

	return ERR_PTR(err);

}



static void xsk_map_free(struct bpf_map *map)
@@ -139,8 +131,7 @@ static void xsk_map_free(struct bpf_map *map) 
	bpf_clear_redirect_map(map);

	synchronize_net();

	free_percpu(m->flush_list);

	bpf_map_area_free(m->xsk_map);

	kfree(m);

	bpf_map_area_free(m);

}



static int xsk_map_get_next_key(struct bpf_map *map, void *key, void *next_key)

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