The patch titled
Subject: mm/memremap: mark folio_span_valid() as __maybe_unused
has been added to the -mm mm-unstable branch. Its filename is
fsdax-introduce-pgmap_request_folios-fix.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/fsdax-introduce-pgmap_request_folios-fix.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Nathan Chancellor <nathan@xxxxxxxxxx>
Subject: mm/memremap: mark folio_span_valid() as __maybe_unused
Date: Tue, 18 Oct 2022 08:26:46 -0700
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.
Link: https://lkml.kernel.org/r/20221018152645.3195108-1-nathan@xxxxxxxxxx
Fixes: ("fsdax: introduce pgmap_request_folios()")
Link: https://github.com/ClangBuiltLinux/linux/issues/1739
Signed-off-by: Nathan Chancellor <nathan@xxxxxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: Nathan Chancellor <nathan@xxxxxxxxxx>
Cc: Tom Rix <trix@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memremap.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
--- a/mm/memremap.c~fsdax-introduce-pgmap_request_folios-fix
+++ a/mm/memremap.c
@@ -530,8 +530,9 @@ void zone_device_page_init(struct page *
}
EXPORT_SYMBOL_GPL(zone_device_page_init);
-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;
_
Patches currently in -mm which might be from nathan@xxxxxxxxxx are
fsdax-introduce-pgmap_request_folios-fix.patch
