Re: [PATCH] kvm: ensure that debugfs entries have been created

[Yang Hamo Bai <hamo.by@gmail.com>]

On Thu, Dec 15, 2011 at 2:23 PM, Hamo <hamo.by@gmail.com> wrote:
> by checking the return value from kvm_init_debug, we
> can ensure that the entries under debugfs for KVM have
> been created correctly.
>
> Signed-off-by: Yang Bai <hamo.by@gmail.com>
> ---
>  virt/kvm/kvm_main.c |   26 +++++++++++++++++++++++---
>  1 files changed, 23 insertions(+), 3 deletions(-)
>
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index d9cfb78..a338273 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -2612,15 +2612,29 @@ static const struct file_operations *stat_fops[] = {
>        [KVM_STAT_VM]   = &vm_stat_fops,
>  };
>
> -static void kvm_init_debug(void)
> +static int kvm_init_debug(void)
>  {
> +       int r = -EFAULT;
>        struct kvm_stats_debugfs_item *p;
>
>        kvm_debugfs_dir = debugfs_create_dir("kvm", NULL);
> -       for (p = debugfs_entries; p->name; ++p)
> +       if (kvm_debugfs_dir == NULL)
> +               goto out;
> +
> +       for (p = debugfs_entries; p->name; ++p) {
>                p->dentry = debugfs_create_file(p->name, 0444, kvm_debugfs_dir,
>                                                (void *)(long)p->offset,
>                                                stat_fops[p->kind]);
> +               if (p->dentry == NULL)
> +                       goto out_dir;
> +       }
> +
> +       return 0;
> +
> +out_dir:
> +       debugfs_remove_recursive(kvm_debugfs_dir);
> +out:
> +       return r;
>  }
>
>  static void kvm_exit_debug(void)
> @@ -2764,10 +2778,16 @@ int kvm_init(void *opaque, unsigned vcpu_size,
> unsigned vcpu_align,
>        kvm_preempt_ops.sched_in = kvm_sched_in;
>        kvm_preempt_ops.sched_out = kvm_sched_out;
>
> -       kvm_init_debug();
> +       r = kvm_init_debug();
> +       if (r) {
> +               printk(KERN_ERR "kvm: create debugfs files failed\n");
> +               goto out_undebugfs;
> +       }
>
>        return 0;
>
> +out_undebugfs:
> +       unregister_syscore_ops(&kvm_syscore_ops);
>  out_unreg:
>        kvm_async_pf_deinit();
>  out_free:
> --
> 1.7.1

Ping.