Re: [PATCH 06/17] Update the infiniband uverbs driver to use idr helper functions.

[Doug Ledford]

On 09/16/2015 01:50 PM, Lee Duncan wrote:
> Signed-off-by: Lee Duncan <lduncan@xxxxxxxx>

Looks OK to me.  The setting of uobj->id is no longer under the lock,
but we won't succeed at an idr lookup until it is set, which means it
won't be found and can't be used in idr_remove_uobj() until after the
uobj->id is set regardless of the lock.

Acked-by: Doug Ledford <dledford@xxxxxxxxxx>

> ---
>  drivers/infiniband/core/uverbs_cmd.c | 12 ++----------
>  1 file changed, 2 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/infiniband/core/uverbs_cmd.c b/drivers/infiniband/core/uverbs_cmd.c
> index bbb02ffe87df..1e5b2a66a501 100644
> --- a/drivers/infiniband/core/uverbs_cmd.c
> +++ b/drivers/infiniband/core/uverbs_cmd.c
> @@ -120,24 +120,16 @@ static int idr_add_uobj(struct idr *idr, struct ib_uobject *uobj)
>  {
>  	int ret;
>  
> -	idr_preload(GFP_KERNEL);
> -	spin_lock(&ib_uverbs_idr_lock);
> -
> -	ret = idr_alloc(idr, uobj, 0, 0, GFP_NOWAIT);
> +	ret = idr_get_index(idr, &ib_uverbs_idr_lock, uobj);
>  	if (ret >= 0)
>  		uobj->id = ret;
>  
> -	spin_unlock(&ib_uverbs_idr_lock);
> -	idr_preload_end();
> -
>  	return ret < 0 ? ret : 0;
>  }
>  
>  void idr_remove_uobj(struct idr *idr, struct ib_uobject *uobj)
>  {
> -	spin_lock(&ib_uverbs_idr_lock);
> -	idr_remove(idr, uobj->id);
> -	spin_unlock(&ib_uverbs_idr_lock);
> +	idr_put_index(idr, &ib_uverbs_idr_lock, uobj->id);
>  }
>  
>  static struct ib_uobject *__idr_get_uobj(struct idr *idr, int id,
> 


-- 
Doug Ledford <dledford@xxxxxxxxxx>
              GPG KeyID: 0E572FDD

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