On 7/2/19 1:54 PM, Andrew Morton wrote:
On Tue, 2 Jul 2019 06:02:03 -0700 Guenter Roeck <linux@xxxxxxxxxxxx> wrote:
Several mips builds generate the following build warning.
mm/gup.c:1788:13: warning: 'undo_dev_pagemap' defined but not used
The function is declared unconditionally but only called from behind
various ifdefs. Mark it __maybe_unused.
...
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -1785,7 +1785,8 @@ static inline pte_t gup_get_pte(pte_t *ptep)
}
#endif /* CONFIG_GUP_GET_PTE_LOW_HIGH */
-static void undo_dev_pagemap(int *nr, int nr_start, struct page **pages)
+static void __maybe_unused undo_dev_pagemap(int *nr, int nr_start,
+ struct page **pages)
{
while ((*nr) - nr_start) {
struct page *page = pages[--(*nr)];
It's not our preferred way of doing it but yes, it would be a bit of a
mess and a bit of a maintenance burden to get the ifdefs correct.
That is why I did it here. I understand that some maintainers don't like it,
and I noticed that it wasn't used elsewhere in the file, but it seemed to be
to most straightforward solution.
And really, __maybe_unused isn't a bad way at all - it ensures that the
function always gets build-tested and the compiler will remove it so we
don't have to play the chase-the-ifdefs game.
Yes, it does have its advantages. I like it myself, but usually I would not
impose my opinion on others. In this case, anything else would have been
quite awkward and be prone to never-ending adjustments.
Thanks,
Guenter
