mm: Fix '.data.once' orphan section warning

Portions of upstream commit 1177b654c1bd ("mm/memcg: warning on !memcg
after readahead page charged") were backported as commit 496aec7e85fc
("mm: add VM_WARN_ON_ONCE_PAGE() macro"). Unfortunately, the backport
did not account for the lack of commit 513c7e624a0f ("treewide: Convert
macro and uses of __section(foo) to __section("foo")") in kernels prior
to 5.10, resulting in the following orphan section warnings on PowerPC
clang builds with CONFIG_DEBUG_VM=y:

  powerpc64le-linux-gnu-ld: warning: orphan section `".data.once"' from `mm/huge_memory.o' being placed in section `".data.once"'
  powerpc64le-linux-gnu-ld: warning: orphan section `".data.once"' from `mm/huge_memory.o' being placed in section `".data.once"'
  powerpc64le-linux-gnu-ld: warning: orphan section `".data.once"' from `mm/huge_memory.o' being placed in section `".data.once"'

This is a difference between how clang and gcc handle macro
stringification, which was resolved for the kernel by not stringifying
the argument to the __section() macro. Since that change was deemed not
suitable for the stable kernels by commit 5d694685cf41 ("once: fix
section mismatch on clang builds"), do that same thing as that change
and remove the quotes from the argument to __section().

Fixes: 496aec7e85fc ("mm: add VM_WARN_ON_ONCE_PAGE() macro")
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Acked-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/include/linux/mmdebug.h b/include/linux/mmdebug.h
index 5d0767cb424aaa3478c8c35e97fe1a723c95b53a..4ed52879ce552c8f79e698bf6d3d81d11da89509 100644 (file)
--- a/include/linux/mmdebug.h
+++ b/include/linux/mmdebug.h
@@ -38,7 +38,7 @@ void dump_mm(const struct mm_struct *mm);
                }                                                       \
        } while (0)
 #define VM_WARN_ON_ONCE_PAGE(cond, page)       ({                      \
-       static bool __section(".data.once") __warned;                   \
+       static bool __section(.data.once) __warned;                     \
        int __ret_warn_once = !!(cond);                                 \
                                                                        \
        if (unlikely(__ret_warn_once && !__warned)) {                   \