x86/mem_sharing: Fix RANDCONFIG build

Commit Message

Andrew Cooper Jan. 7, 2020, 1:49 p.m. UTC

Travis reports: https://travis-ci.org/andyhhp/xen/jobs/633751811

  mem_sharing.c:361:13: error: 'rmap_has_entries' defined but not used [-Werror=unused-function]
   static bool rmap_has_entries(const struct page_info *page)
               ^
  cc1: all warnings being treated as errors

This happens in a release build (disables MEM_SHARING_AUDIT) when
CONFIG_MEM_SHARING is enabled.

Mark the helper as maybe_unused.

Signed-off-by: Andrew Cooper <[e-mail]>
---
CC: Tamas K Lengyel <[e-mail]>

The alternative is to delete the helper and opencode it for its one caller.
---
 xen/arch/x86/mm/mem_sharing.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Tamas K Lengyel Jan. 7, 2020, 2:58 p.m. UTC | #1

On Tue, Jan 7, 2020 at 6:49 AM Andrew Cooper <[e-mail]> wrote:
>
> Travis reports: https://travis-ci.org/andyhhp/xen/jobs/633751811
>
>   mem_sharing.c:361:13: error: 'rmap_has_entries' defined but not used [-Werror=unused-function]
>    static bool rmap_has_entries(const struct page_info *page)
>                ^
>   cc1: all warnings being treated as errors
>
> This happens in a release build (disables MEM_SHARING_AUDIT) when
> CONFIG_MEM_SHARING is enabled.

My bad, seemed to have missed this somehow.

>
> Mark the helper as maybe_unused.
>
> Signed-off-by: Andrew Cooper <[e-mail]>
> ---
> CC: Tamas K Lengyel <[e-mail]>
>
> The alternative is to delete the helper and opencode it for its one caller.

IMHO that would be better, no reason to keep this trivial check as a
separate function for one caller. Same stands for the
rmap_has_one_entry function as well (feel free to bunch that in too
but I could also do that separately).

Thanks,
Tamas

Patch

diff --git a/xen/arch/x86/mm/mem_sharing.c b/xen/arch/x86/mm/mem_sharing.c
index ddf1f0f9f9..0a1550ffd2 100644
--- a/xen/arch/x86/mm/mem_sharing.c
+++ b/xen/arch/x86/mm/mem_sharing.c
@@ -358,7 +358,7 @@  static bool rmap_has_one_entry(const struct page_info *page)
 }
 
 /* Returns true if the rmap has any entries. O(1) complexity. */
-static bool rmap_has_entries(const struct page_info *page)
+static bool __maybe_unused rmap_has_entries(const struct page_info *page)
 {
     return rmap_count(page) != 0;
 }