Re: [PATCH net] Revert "net: fix cpu_max_bits_warn() usage in netif_attrmask_next{,_and}"

[Guenter Roeck <linux@roeck-us.net>]

On Fri, Oct 14, 2022 at 09:07:46AM -0700, Jakub Kicinski wrote:
> This reverts commit 854701ba4c39afae2362ba19a580c461cb183e4f.
> 
> We have more violations around, which leads to:
> 
>   WARNING: CPU: 2 PID: 1 at include/linux/cpumask.h:110 __netif_set_xps_queue+0x14e/0x770
> 
> Let's back this out and retry with a larger clean up in -next.
> 
> Fixes: 854701ba4c39 ("net: fix cpu_max_bits_warn() usage in netif_attrmask_next{,_and}")
> Link: https://lore.kernel.org/all/20221014030459.3272206-2-guoren@kernel.org/
> Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Tested-by: Guenter Roeck <linux@roeck-us.net>

> ---
>  include/linux/netdevice.h | 10 ++++++----
>  1 file changed, 6 insertions(+), 4 deletions(-)
> 
> diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
> index a36edb0ec199..eddf8ee270e7 100644
> --- a/include/linux/netdevice.h
> +++ b/include/linux/netdevice.h
> @@ -3663,8 +3663,9 @@ static inline bool netif_attr_test_online(unsigned long j,
>  static inline unsigned int netif_attrmask_next(int n, const unsigned long *srcp,
>  					       unsigned int nr_bits)
>  {
> -	/* n is a prior cpu */
> -	cpu_max_bits_warn(n + 1, nr_bits);
> +	/* -1 is a legal arg here. */
> +	if (n != -1)
> +		cpu_max_bits_warn(n, nr_bits);
>  
>  	if (srcp)
>  		return find_next_bit(srcp, nr_bits, n + 1);
> @@ -3685,8 +3686,9 @@ static inline int netif_attrmask_next_and(int n, const unsigned long *src1p,
>  					  const unsigned long *src2p,
>  					  unsigned int nr_bits)
>  {
> -	/* n is a prior cpu */
> -	cpu_max_bits_warn(n + 1, nr_bits);
> +	/* -1 is a legal arg here. */
> +	if (n != -1)
> +		cpu_max_bits_warn(n, nr_bits);
>  
>  	if (src1p && src2p)
>  		return find_next_and_bit(src1p, src2p, nr_bits, n + 1);
> -- 
> 2.37.3
>