xsk: Make xskmap flush_list common for all map instances

The xskmap flush list is used to track entries that need to flushed
from via the xdp_do_flush_map() function. This list used to be
per-map, but there is really no reason for that. Instead make the
flush list global for all xskmaps, which simplifies __xsk_map_flush()
and xsk_map_alloc().

Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/bpf/20191219061006.21980-5-bjorn.topel@gmail.com

diff --git a/include/net/xdp_sock.h b/include/net/xdp_sock.h
index e3780e4..4859474 100644 (file)
--- a/include/net/xdp_sock.h
+++ b/include/net/xdp_sock.h
@@ -72,7 +72,6 @@ struct xdp_umem {
 
 struct xsk_map {
        struct bpf_map map;
-       struct list_head __percpu *flush_list;
        spinlock_t lock; /* Synchronize map updates */
        struct xdp_sock *xsk_map[];
 };
@@ -139,9 +138,8 @@ void xsk_map_try_sock_delete(struct xsk_map *map, struct xdp_sock *xs,
                             struct xdp_sock **map_entry);
 int xsk_map_inc(struct xsk_map *map);
 void xsk_map_put(struct xsk_map *map);
-int __xsk_map_redirect(struct bpf_map *map, struct xdp_buff *xdp,
-                      struct xdp_sock *xs);
-void __xsk_map_flush(struct bpf_map *map);
+int __xsk_map_redirect(struct xdp_sock *xs, struct xdp_buff *xdp);
+void __xsk_map_flush(void);
 
 static inline struct xdp_sock *__xsk_map_lookup_elem(struct bpf_map *map,
                                                     u32 key)
@@ -369,13 +367,12 @@ static inline u64 xsk_umem_adjust_offset(struct xdp_umem *umem, u64 handle,
        return 0;
 }
 
-static inline int __xsk_map_redirect(struct bpf_map *map, struct xdp_buff *xdp,
-                                    struct xdp_sock *xs)
+static inline int __xsk_map_redirect(struct xdp_sock *xs, struct xdp_buff *xdp)
 {
        return -EOPNOTSUPP;
 }
 
-static inline void __xsk_map_flush(struct bpf_map *map)
+static inline void __xsk_map_flush(void)
 {
 }
 

diff --git a/kernel/bpf/xskmap.c b/kernel/bpf/xskmap.c
index 90c4fce..2cc5c8f 100644 (file)
--- a/kernel/bpf/xskmap.c
+++ b/kernel/bpf/xskmap.c
@@ -72,9 +72,9 @@ 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;
+       int err, numa_node;
        struct xsk_map *m;
-       u64 cost, size;
+       u64 size;
 
        if (!capable(CAP_NET_ADMIN))
                return ERR_PTR(-EPERM);
@@ -86,9 +86,8 @@ static struct bpf_map *xsk_map_alloc(union bpf_attr *attr)
 
        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);
+       err = bpf_map_charge_init(&mem, size);
        if (err < 0)
                return ERR_PTR(err);
 
@@ -102,16 +101,6 @@ static struct bpf_map *xsk_map_alloc(union bpf_attr *attr)
        bpf_map_charge_move(&m->map.memory, &mem);
        spin_lock_init(&m->lock);
 
-       m->flush_list = alloc_percpu(struct list_head);
-       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));
-
        return &m->map;
 }
 
@@ -121,7 +110,6 @@ 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);
 }
 

diff --git a/net/core/filter.c b/net/core/filter.c
index a411f78..c51678c 100644 (file)
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -3511,8 +3511,7 @@ err:
 
 static int __bpf_tx_xdp_map(struct net_device *dev_rx, void *fwd,
                            struct bpf_map *map,
-                           struct xdp_buff *xdp,
-                           u32 index)
+                           struct xdp_buff *xdp)
 {
        int err;
 
@@ -3537,7 +3536,7 @@ static int __bpf_tx_xdp_map(struct net_device *dev_rx, void *fwd,
        case BPF_MAP_TYPE_XSKMAP: {
                struct xdp_sock *xs = fwd;
 
-               err = __xsk_map_redirect(map, xdp, xs);
+               err = __xsk_map_redirect(xs, xdp);
                return err;
        }
        default:
@@ -3562,7 +3561,7 @@ void xdp_do_flush_map(void)
                        __cpu_map_flush(map);
                        break;
                case BPF_MAP_TYPE_XSKMAP:
-                       __xsk_map_flush(map);
+                       __xsk_map_flush();
                        break;
                default:
                        break;
@@ -3619,7 +3618,7 @@ static int xdp_do_redirect_map(struct net_device *dev, struct xdp_buff *xdp,
        if (ri->map_to_flush && unlikely(ri->map_to_flush != map))
                xdp_do_flush_map();
 
-       err = __bpf_tx_xdp_map(dev, fwd, map, xdp, index);
+       err = __bpf_tx_xdp_map(dev, fwd, map, xdp);
        if (unlikely(err))
                goto err;
 

diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
index 9567938..e45c27f 100644 (file)
--- a/net/xdp/xsk.c
+++ b/net/xdp/xsk.c
@@ -31,6 +31,8 @@
 
 #define TX_BATCH_SIZE 16
 
+static DEFINE_PER_CPU(struct list_head, xskmap_flush_list);
+
 bool xsk_is_setup_for_bpf_map(struct xdp_sock *xs)
 {
        return READ_ONCE(xs->rx) &&  READ_ONCE(xs->umem) &&
@@ -264,11 +266,9 @@ out_unlock:
        return err;
 }
 
-int __xsk_map_redirect(struct bpf_map *map, struct xdp_buff *xdp,
-                      struct xdp_sock *xs)
+int __xsk_map_redirect(struct xdp_sock *xs, struct xdp_buff *xdp)
 {
-       struct xsk_map *m = container_of(map, struct xsk_map, map);
-       struct list_head *flush_list = this_cpu_ptr(m->flush_list);
+       struct list_head *flush_list = this_cpu_ptr(&xskmap_flush_list);
        int err;
 
        err = xsk_rcv(xs, xdp);
@@ -281,10 +281,9 @@ int __xsk_map_redirect(struct bpf_map *map, struct xdp_buff *xdp,
        return 0;
 }
 
-void __xsk_map_flush(struct bpf_map *map)
+void __xsk_map_flush(void)
 {
-       struct xsk_map *m = container_of(map, struct xsk_map, map);
-       struct list_head *flush_list = this_cpu_ptr(m->flush_list);
+       struct list_head *flush_list = this_cpu_ptr(&xskmap_flush_list);
        struct xdp_sock *xs, *tmp;
 
        list_for_each_entry_safe(xs, tmp, flush_list, flush_node) {
@@ -1177,7 +1176,7 @@ static struct pernet_operations xsk_net_ops = {
 
 static int __init xsk_init(void)
 {
-       int err;
+       int err, cpu;
 
        err = proto_register(&xsk_proto, 0 /* no slab */);
        if (err)
@@ -1195,6 +1194,8 @@ static int __init xsk_init(void)
        if (err)
                goto out_pernet;
 
+       for_each_possible_cpu(cpu)
+               INIT_LIST_HEAD(&per_cpu(xskmap_flush_list, cpu));
        return 0;
 
 out_pernet: