Re: [Intel-wired-lan] [PATCH] [v2] ethernet: intel: fix building with large NR_CPUS

[Alexander Lobakin]

From: Arnd Bergmann <arnd@xxxxxxxxxx>
Date: Fri, 20 Jun 2025 19:31:24 +0200

> From: Arnd Bergmann <arnd@xxxxxxxx>
> 
> With large values of CONFIG_NR_CPUS, three Intel ethernet drivers fail to
> compile like:
> 
> In function ‘i40e_free_q_vector’,
>     inlined from ‘i40e_vsi_alloc_q_vectors’ at drivers/net/ethernet/intel/i40e/i40e_main.c:12112:3:
>   571 |         _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
> include/linux/rcupdate.h:1084:17: note: in expansion of macro ‘BUILD_BUG_ON’
>  1084 |                 BUILD_BUG_ON(offsetof(typeof(*(ptr)), rhf) >= 4096);    \
> drivers/net/ethernet/intel/i40e/i40e_main.c:5113:9: note: in expansion of macro ‘kfree_rcu’
>  5113 |         kfree_rcu(q_vector, rcu);
>       |         ^~~~~~~~~
> 
> The problem is that the 'rcu' member in 'q_vector' is too far from the start
> of the structure. Move this member before the CPU mask instead, in all three
> drivers.
> 
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>

Reviewed-by: Alexander Lobakin <aleksander.lobakin@xxxxxxxxx>

> ---
> v2: move rcu to just after the napi_struct [Alexander Lobakin]

Thanks!
Olek