# Re: \[PATCH net\] net: napi: Make napi\_defer\_irqs u32

- From: Eric Dumazet \<hidden\>
- Date: 2024-09-02 13:01:44 
- List: netdev
- Page: https://ratatoskr.run/netdev/2024/09/2731377
- Thread: https://ratatoskr.run/netdev/2024/08/2729936/t.md

```text
On Sat, Aug 31, 2024 at 1:32 PM Joe Damato [ref] wrote:
>
> In commit 6f8b12d661d0 ("net: napi: add hard irqs deferral feature")
> napi_defer_irqs was added to net_device and napi_defer_irqs_count was
> added to napi_struct, both as type int.
>
> This value never goes below zero. Change the type for both from int to
> u32, and add an overflow check to sysfs to limit the value to S32_MAX.
>
> Before this patch:
>
> $ sudo bash -c 'echo 2147483649 > /sys/class/net/eth4/napi_defer_hard_irqs'
> $ cat /sys/class/net/eth4/napi_defer_hard_irqs
> -2147483647
>
> After this patch:
>
> $ sudo bash -c 'echo 2147483649 > /sys/class/net/eth4/napi_defer_hard_irqs'
> bash: line 0: echo: write error: Numerical result out of range
>
> Fixes: 6f8b12d661d0 ("net: napi: add hard irqs deferral feature")
> Cc: stable@kernel.org
> Cc: Eric Dumazet <redacted>
> Suggested-by: Jakub Kicinski <kuba@kernel.org>
> Signed-off-by: Joe Damato <redacted>
> ---

I do not think this deserves a change to stable trees.

Signed or unsigned, what is the issue ?

Do you really need one extra bit ?

/sys/class/net/XXXXX/tx_queue_len has a similar behavior.
```