Re: [PATCH] kvm: vfio: Convert kvm_vfio_file_add() to use CLASS(fd) and guard(mutex)

[Alex Williamson]

On Sat, 23 May 2026 10:32:42 +0530
Yash Suthar <yashsuthar983@xxxxxxxxx> wrote:

> Convert manual fget/fput call to CLASS(fd, f) and
> mutex_lock/unlock to guard(mutex).
> 
> This remove the goto based paths both out_unlock and
> out_fput.
> 
> Signed-off-by: Yash Suthar <yashsuthar983@xxxxxxxxx>
> ---
>  virt/kvm/vfio.c | 37 ++++++++++++++-----------------------
>  1 file changed, 14 insertions(+), 23 deletions(-)

Sean already took Carlos' series[1] that mostly 


> diff --git a/virt/kvm/vfio.c b/virt/kvm/vfio.c
> index 9f9acb66cc1e..bb3694d9c0c4 100644
> --- a/virt/kvm/vfio.c
> +++ b/virt/kvm/vfio.c
> @@ -144,45 +144,36 @@ static int kvm_vfio_file_add(struct kvm_device *dev, unsigned int fd)
>  {
>  	struct kvm_vfio *kv = dev->private;
>  	struct kvm_vfio_file *kvf;
> -	struct file *filp;
> -	int ret = 0;
> +	struct file *file;
> +	CLASS(fd, f)(fd);
>  
> -	filp = fget(fd);
> -	if (!filp)
> +	if (fd_empty(f))
>  		return -EBADF;
>  
> +	file = fd_file(f);
> +
>  	/* Ensure the FD is a vfio FD. */
> -	if (!kvm_vfio_file_is_valid(filp)) {
> -		ret = -EINVAL;
> -		goto out_fput;
> -	}
> +	if (!kvm_vfio_file_is_valid(file))
> +		return -EINVAL;
>  
> -	mutex_lock(&kv->lock);
> +	guard(mutex)(&kv->lock);
>  
>  	list_for_each_entry(kvf, &kv->file_list, node) {
> -		if (kvf->file == filp) {
> -			ret = -EEXIST;
> -			goto out_unlock;
> -		}
> +		if (kvf->file == file)
> +			return -EEXIST;
>  	}
>  
>  	kvf = kzalloc_obj(*kvf, GFP_KERNEL_ACCOUNT);
> -	if (!kvf) {
> -		ret = -ENOMEM;
> -		goto out_unlock;
> -	}
> +	if (!kvf)
> +		return -ENOMEM;
>  
> -	kvf->file = get_file(filp);
> +	kvf->file = get_file(file);
>  	list_add_tail(&kvf->node, &kv->file_list);
>  
>  	kvm_vfio_file_set_kvm(kvf->file, dev->kvm);
>  	kvm_vfio_update_coherency(dev);
>  
> -out_unlock:
> -	mutex_unlock(&kv->lock);
> -out_fput:
> -	fput(filp);
> -	return ret;
> +	return 0;
>  }
>  
>  static int kvm_vfio_file_del(struct kvm_device *dev, unsigned int fd)