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| author | Nathan Chancellor <nathan@kernel.org> | 2022-12-13 11:35:28 -0700 |
|---|---|---|
| committer | Masahiro Yamada <masahiroy@kernel.org> | 2022-12-14 15:49:24 +0900 |
| commit | 0d24f1b7cc65ee73ea8d04e0d10f77a7cb7a83f3 (patch) | |
| tree | 44b18b2157adeffa9eb24ffb38f53d8ab2b735b7 /kernel/padata.c | |
| parent | 87d599fc3955e59b1ed30f350321a4be5353f945 (diff) | |
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 because it inlined the other call to
padata_work_init() with padata_parallel_worker(), meaning the remaining
uses of padata_work_init() use padata_mt_helper() as the work_fn
argument. This optimization causes modpost to complain since
padata_work_init() is not __init, whereas padata_mt_helper() is.
Since padata_work_init() is only called from __init code when
padata_mt_helper() is passed as the work_fn argument, mark
padata_work_init() as __ref, which makes it clear to modpost that this
scenario is okay.
Suggested-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Acked-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Diffstat (limited to 'kernel/padata.c')
| -rw-r--r-- | kernel/padata.c | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/kernel/padata.c b/kernel/padata.c index e5819bb8bd1d..d175cc000453 100644 --- a/kernel/padata.c +++ b/kernel/padata.c @@ -83,8 +83,16 @@ 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) +/* + * This function is marked __ref because this function may be optimized in such + * a way that it directly refers to work_fn's address, which causes modpost to + * complain when work_fn is marked __init. This scenario was observed with clang + * LTO, where padata_work_init() was optimized to refer directly to + * padata_mt_helper() because the calls to padata_work_init() with other work_fn + * values were eliminated or inlined. + */ +static void __ref 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); |