Re: [PATCH] net: psp: select CONFIG_SKB_EXTENSIONS

[Simon Horman <horms@kernel.org>]

On Mon, Feb 16, 2026 at 11:54:54AM +0100, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
> 
> psp now uses skb extensions, failing to build when that is disabled:
> 
> In file included from include/net/psp.h:7,
>                  from net/psp/psp_sock.c:9:
> include/net/psp/functions.h: In function '__psp_skb_coalesce_diff':
> include/net/psp/functions.h:60:13: error: implicit declaration of function 'skb_ext_find'; did you mean 'skb_ext_copy'? [-Wimplicit-function-declaration]
>    60 |         a = skb_ext_find(one, SKB_EXT_PSP);
>       |             ^~~~~~~~~~~~
>       |             skb_ext_copy
> include/net/psp/functions.h:60:31: error: 'SKB_EXT_PSP' undeclared (first use in this function)
>    60 |         a = skb_ext_find(one, SKB_EXT_PSP);
>       |                               ^~~~~~~~~~~
> include/net/psp/functions.h:60:31: note: each undeclared identifier is reported only once for each function it appears in
> include/net/psp/functions.h: In function '__psp_sk_rx_policy_check':
> include/net/psp/functions.h:94:53: error: 'SKB_EXT_PSP' undeclared (first use in this function)
>    94 |         struct psp_skb_ext *pse = skb_ext_find(skb, SKB_EXT_PSP);
>       |                                                     ^~~~~~~~~~~
> net/psp/psp_sock.c: In function 'psp_sock_recv_queue_check':
> net/psp/psp_sock.c:164:41: error: 'SKB_EXT_PSP' undeclared (first use in this function)
>   164 |                 pse = skb_ext_find(skb, SKB_EXT_PSP);
>       |                                         ^~~~~~~~~~~
> 
> Select the Kconfig symbol as we do from its other users.
> 
> Fixes: 6b46ca260e22 ("net: psp: add socket security association code")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>  net/psp/Kconfig | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/net/psp/Kconfig b/net/psp/Kconfig
> index 371e8771f3bd..84d6b0f25460 100644
> --- a/net/psp/Kconfig
> +++ b/net/psp/Kconfig
> @@ -6,6 +6,7 @@ config INET_PSP
>  	bool "PSP Security Protocol support"
>  	depends on INET
>  	select SKB_DECRYPTED
> +	select SKB_EXTENSIONS
>  	select SOCK_VALIDATE_XMIT
>  	help
>  	Enable kernel support for the PSP Security Protocol (PSP).

I agree that the is written in such a way that it assumes this is available.
And select is an appropriate way to do so.

Reviewed-by: Simon Horman <horms@kernel.org>