| Message ID | 20221018152645.3195108-1-nathan@kernel.org (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | mm/memremap: Mark folio_span_valid() as __maybe_unused | expand |
Nathan Chancellor wrote: > When building without CONFIG_DEBUG_VM, clang warns: > > mm/memremap.c:495:13: error: function 'folio_span_valid' is not needed and will not be emitted [-Werror,-Wunneeded-internal-declaration] > static bool folio_span_valid(struct dev_pagemap *pgmap, struct folio *folio, > ^ > 1 error generated. > > folio_span_valid() is only used within a instance of VM_WARN_ON_ONCE(), > which evaluates to BUILD_BUG_ON_INVALID() with CONFIG_DEBUG_VM=n, which > ultimately resolves to sizeof(), which is fully resolved at compile > time. Basically, the warning is flagging that folio_span_valid() is > only used in a compile time context and will not be called at run time. > > Since this is expected given the configuration, mark folio_span_valid() > as __maybe_unused so that there is no warning. > > Fixes: 07108d5bfeeb ("fsdax: introduce pgmap_request_folios()") > Link: https://github.com/ClangBuiltLinux/linux/issues/1739 > Signed-off-by: Nathan Chancellor <nathan@kernel.org> > --- > > I am aware the Fixes SHA is probably not stable but I figured I would > include it anyways. This fix looks good to me, but I assume commit-ids are not stable until the patch moves from mm-unstable to mm-stable. Andrew, do I have that right?
On Tue, 18 Oct 2022 10:54:58 -0700 Dan Williams <dan.j.williams@intel.com> wrote: > > --- > > > > I am aware the Fixes SHA is probably not stable but I figured I would > > include it anyways. > > This fix looks good to me, but I assume commit-ids are not stable until > the patch moves from mm-unstable to mm-stable. Andrew, do I have that > right? Yes, mm-unstable hashes change daily. But knowing the title of the patch which needs the fix is quite helpful.
diff --git a/mm/memremap.c b/mm/memremap.c index 53fe30bb79bb..02b796749b72 100644 --- a/mm/memremap.c +++ b/mm/memremap.c @@ -492,8 +492,9 @@ void free_zone_device_page(struct page *page) put_dev_pagemap(page->pgmap); } -static bool folio_span_valid(struct dev_pagemap *pgmap, struct folio *folio, - int nr_folios) +static __maybe_unused bool folio_span_valid(struct dev_pagemap *pgmap, + struct folio *folio, + int nr_folios) { unsigned long pfn_start, pfn_end;
When building without CONFIG_DEBUG_VM, clang warns: mm/memremap.c:495:13: error: function 'folio_span_valid' is not needed and will not be emitted [-Werror,-Wunneeded-internal-declaration] static bool folio_span_valid(struct dev_pagemap *pgmap, struct folio *folio, ^ 1 error generated. folio_span_valid() is only used within a instance of VM_WARN_ON_ONCE(), which evaluates to BUILD_BUG_ON_INVALID() with CONFIG_DEBUG_VM=n, which ultimately resolves to sizeof(), which is fully resolved at compile time. Basically, the warning is flagging that folio_span_valid() is only used in a compile time context and will not be called at run time. Since this is expected given the configuration, mark folio_span_valid() as __maybe_unused so that there is no warning. Fixes: 07108d5bfeeb ("fsdax: introduce pgmap_request_folios()") Link: https://github.com/ClangBuiltLinux/linux/issues/1739 Signed-off-by: Nathan Chancellor <nathan@kernel.org> --- I am aware the Fixes SHA is probably not stable but I figured I would include it anyways. mm/memremap.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) base-commit: f5938bbbb79d48ca167e305c228dccbecea0309e