linux-kernel - [PATCH v2 1/2] padata: Mark padata_work_init() as _

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Message-Id: <20221207191657.2852229-2-nathan@kernel.org>
Date:   Wed,  7 Dec 2022 12:16:56 -0700
From:   Nathan Chancellor <nathan@...nel.org>
To:     Masahiro Yamada <masahiroy@...nel.org>
Cc:     Nick Desaulniers <ndesaulniers@...gle.com>,
        Tom Rix <trix@...hat.com>, Nicolas Schier <nicolas@...sle.eu>,
        Sami Tolvanen <samitolvanen@...gle.com>,
        Vincent Donnefort <vdonnefort@...gle.com>,
        linux-kbuild@...r.kernel.org, linux-kernel@...r.kernel.org,
        llvm@...ts.linux.dev, patches@...ts.linux.dev,
        Nathan Chancellor <nathan@...nel.org>,
        Daniel Jordan <daniel.m.jordan@...cle.com>,
        Steffen Klassert <steffen.klassert@...unet.com>,
        linux-crypto@...r.kernel.org
Subject: [PATCH v2 1/2] padata: Mark padata_work_init() as __ref

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.

Suggested-by: Daniel Jordan <daniel.m.jordan@...cle.com>
Signed-off-by: Nathan Chancellor <nathan@...nel.org>
---
Cc: Steffen Klassert <steffen.klassert@...unet.com>
Cc: Daniel Jordan <daniel.m.jordan@...cle.com>
Cc: linux-crypto@...r.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