Re: [PATCH] Revert "mm/page_alloc: make should_fail_alloc_page() static"

[Mel Gorman]

On Mon, Jul 05, 2021 at 12:38:06PM +0200, Marco Elver wrote:
> This reverts commit f7173090033c70886d925995e9dfdfb76dbb2441.
> 
> Commit 76cd61739fd1 ("mm/error_inject: Fix allow_error_inject function
> signatures") explicitly made should_fail_alloc_page() non-static, due to
> worries of remaining compiler optimizations in the absence of function
> side-effects while being noinline.
> 
> Furthermore, kernel/bpf/verifier.c pushes should_fail_alloc_page onto
> the btf_non_sleepable_error_inject BTF IDs set, which when enabling
> CONFIG_DEBUG_INFO_BTF results in an error at the BTFIDS stage:
> 
>   FAILED unresolved symbol should_fail_alloc_page
> 
> To avoid the W=1 warning, add a function declaration right above the
> function itself, with a comment it is required in a BTF IDs set.
> 
> Fixes: f7173090033c ("mm/page_alloc: make should_fail_alloc_page() static")
> Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
> Cc: Alexei Starovoitov <ast@xxxxxxxxxx>
> Signed-off-by: Marco Elver <elver@xxxxxxxxxx>

Acked-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>

Out of curiousity though, why does block/blk-core.c not require
something similar for should_fail_bio?

-- 
Mel Gorman
SUSE Labs