Re: [PATCH net] net: sched: don't use GFP_KERNEL under spin lock

[Eric Dumazet]

On Tue, 2017-09-05 at 03:54 -0700, Jakub Kicinski wrote:
> The new TC IDR code uses GFP_KERNEL under spinlocks.  Which leads
> to:

> ...
> 
> Fixes: 65a206c01e8e ("net/sched: Change act_api and act_xxx modules to use 
> IDR")
> Signed-off-by: Jakub Kicinski <jakub.kicin...@netronome.com>
> Reviewed-by: Simon Horman <simon.hor...@netronome.com>
> ---
>  net/sched/act_api.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/net/sched/act_api.c b/net/sched/act_api.c
> index 0eb545bcb247..a48e4b45722d 100644
> --- a/net/sched/act_api.c
> +++ b/net/sched/act_api.c
> @@ -298,7 +298,7 @@ int tcf_idr_create(struct tc_action_net *tn, u32 index, 
> struct nlattr *est,
>       if (!index) {


                idr_preload(GFP_KERNEL);

>               spin_lock_bh(&idrinfo->lock);
>               err = idr_alloc_ext(idr, NULL, &idr_index, 1, 0,
> -                                 GFP_KERNEL);
> +                                 GFP_ATOMIC);
>               spin_unlock_bh(&idrinfo->lock);
>               if (err) {
>  err3:
> @@ -309,7 +309,7 @@ int tcf_idr_create(struct tc_action_net *tn, u32 index, 
> struct nlattr *est,
>       } else {

                idr_preload(GFP_KERNEL);

>               spin_lock_bh(&idrinfo->lock);
>               err = idr_alloc_ext(idr, NULL, NULL, index, index + 1,
> -                                 GFP_KERNEL);
> +                                 GFP_ATOMIC);
>               spin_unlock_bh(&idrinfo->lock);
>               if (err)
>                       goto err3;