Subject: Re: [PATCH v4 net-next 03/14] net: Use nested-BH locking for napi_alloc_cache.

From: Jakub Kicinski <[email-masked]>
Date: Wed, 5 Jun 2024 19:54:20 -0700

On Tue,  4 Jun 2024 17:24:10 +0200 Sebastian Andrzej Siewior wrote:
> @@ -308,6 +311,7 @@ void *__napi_alloc_frag_align(unsigned int fragsz, unsigned int align_mask)
>  	struct napi_alloc_cache *nc = this_cpu_ptr(&napi_alloc_cache);
>  
>  	fragsz = SKB_DATA_ALIGN(fragsz);
> +	guard(local_lock_nested_bh)(&napi_alloc_cache.bh_lock);
>  
>  	return __page_frag_alloc_align(&nc->page, fragsz, GFP_ATOMIC,
>  				       align_mask);

We have decided to advise against the use of guard() in networking, 
at least for now.

Andrew, wasn't it on your TODO list to send the update to the docs? :)