Re: [PATCH v2 1/2] padata: Mark padata_work_init() as __ref

Daniel Jordan
2022-12-07T19:57:16Z

On Wed, Dec 07, 2022 at 12:16:56PM -0700, Nathan Chancellor wrote:
> When building arm64 allmodconfig + ThinLTO with clang and a proposed
> modpost update to account for -ffuncton-sections, the following warning
> appears:
>
> WARNING: modpost: vmlinux.o: section mismatch in reference: padata_work_init (section: .text.padata_work_init) -> padata_mt_helper (section: .init.text)
> WARNING: modpost: vmlinux.o: section mismatch in reference: padata_work_init (section: .text.padata_work_init) -> padata_mt_helper (section: .init.text)
>
> LLVM has optimized padata_work_init() to include the address of
> padata_mt_helper() directly, which causes modpost to complain since
> padata_work_init() is not __init, whereas padata_mt_helper() is. In
> reality, padata_work_init() is only called with padata_mt_helper() as
> the work_fn argument in code that is __init, so this warning will not
> result in any problems. Silence it with __ref, which makes it clear to
> modpost that padata_work_init() can only use padata_mt_helper() in
> __init code.

Thanks!

Acked-by: Daniel Jordan <daniel.m.jordan@oracle.com>

> Suggested-by: Daniel Jordan <daniel.m.jordan@oracle.com>
> Signed-off-by: Nathan Chancellor <nathan@kernel.org>
> ---
> Cc: Steffen Klassert <steffen.klassert@secunet.com>
> Cc: Daniel Jordan <daniel.m.jordan@oracle.com>
> Cc: linux-crypto@vger.kernel.org
> ---
> kernel/padata.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/padata.c b/kernel/padata.c
> index e5819bb8bd1d..4c3137fe8449 100644
> --- a/kernel/padata.c
> +++ b/kernel/padata.c
> @@ -83,8 +83,8 @@ static struct padata_work *padata_work_alloc(void)
> return pw;
> }
>
> -static void padata_work_init(struct padata_work *pw, work_func_t work_fn,
> - void *data, int flags)
> +static __ref void padata_work_init(struct padata_work *pw, work_func_t work_fn,
> + void *data, int flags)
> {
> if (flags & PADATA_WORK_ONSTACK)
> INIT_WORK_ONSTACK(&pw->pw_work, work_fn);
>
> base-commit: 76dcd734eca23168cb008912c0f69ff408905235
> --
> 2.38.1
>