| Message ID | 1562072523-22311-1-git-send-email-linux@roeck-us.net (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [-next] mm: Mark undo_dev_pagemap as __maybe_unused | expand |
On Tue, 2 Jul 2019 06:02:03 -0700 Guenter Roeck <linux@roeck-us.net> 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. 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.
On 7/2/19 1:54 PM, Andrew Morton wrote: > On Tue, 2 Jul 2019 06:02:03 -0700 Guenter Roeck <linux@roeck-us.net> 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
diff --git a/mm/gup.c b/mm/gup.c index 7dde2e3a1963..95a373bd8f21 100644 --- 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)];
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. Signed-off-by: Guenter Roeck <linux@roeck-us.net> --- mm/gup.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)