Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

[linux-2.6-microblaze.git] / kernel / bpf / core.c

diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 7b62df8..c6be15a 100644 (file)
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -1381,6 +1381,75 @@ struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err)
 }
 EXPORT_SYMBOL_GPL(bpf_prog_select_runtime);
 
+/* to avoid allocating empty bpf_prog_array for cgroups that
+ * don't have bpf program attached use one global 'empty_prog_array'
+ * It will not be modified the caller of bpf_prog_array_alloc()
+ * (since caller requested prog_cnt == 0)
+ * that pointer should be 'freed' by bpf_prog_array_free()
+ */
+static struct {
+       struct bpf_prog_array hdr;
+       struct bpf_prog *null_prog;
+} empty_prog_array = {
+       .null_prog = NULL,
+};
+
+struct bpf_prog_array __rcu *bpf_prog_array_alloc(u32 prog_cnt, gfp_t flags)
+{
+       if (prog_cnt)
+               return kzalloc(sizeof(struct bpf_prog_array) +
+                              sizeof(struct bpf_prog *) * (prog_cnt + 1),
+                              flags);
+
+       return &empty_prog_array.hdr;
+}
+
+void bpf_prog_array_free(struct bpf_prog_array __rcu *progs)
+{
+       if (!progs ||
+           progs == (struct bpf_prog_array __rcu *)&empty_prog_array.hdr)
+               return;
+       kfree_rcu(progs, rcu);
+}
+
+int bpf_prog_array_length(struct bpf_prog_array __rcu *progs)
+{
+       struct bpf_prog **prog;
+       u32 cnt = 0;
+
+       rcu_read_lock();
+       prog = rcu_dereference(progs)->progs;
+       for (; *prog; prog++)
+               cnt++;
+       rcu_read_unlock();
+       return cnt;
+}
+
+int bpf_prog_array_copy_to_user(struct bpf_prog_array __rcu *progs,
+                               __u32 __user *prog_ids, u32 cnt)
+{
+       struct bpf_prog **prog;
+       u32 i = 0, id;
+
+       rcu_read_lock();
+       prog = rcu_dereference(progs)->progs;
+       for (; *prog; prog++) {
+               id = (*prog)->aux->id;
+               if (copy_to_user(prog_ids + i, &id, sizeof(id))) {
+                       rcu_read_unlock();
+                       return -EFAULT;
+               }
+               if (++i == cnt) {
+                       prog++;
+                       break;
+               }
+       }
+       rcu_read_unlock();
+       if (*prog)
+               return -ENOSPC;
+       return 0;
+}
+
 static void bpf_prog_free_deferred(struct work_struct *work)
 {
        struct bpf_prog_aux *aux;