[PATCH] xen/grant-table: scope gnttab suspend and resume helpers to hibernate callbacks

[Pengpeng Hou <pengpeng.hou@xxxxxxxxxxxxxxxx>]

From: pengpeng.hou@xxxxxxxxxxxxxxxx

In current linux.git (1954c4f01220), gnttab_suspend() and
gnttab_resume() are defined and declared unconditionally. However,
their only in-tree callers reside in drivers/xen/manage.c, which are
guarded by #ifdef CONFIG_HIBERNATE_CALLBACKS.

Match the helper scope to their callers by wrapping the definitions in
CONFIG_HIBERNATE_CALLBACKS and providing no-op stubs in the header. This
fixes the config-scope mismatch and reduces the code footprint when
hibernation callbacks are disabled.

Signed-off-by: pengpeng.hou@xxxxxxxxxxxxxxxx
---
diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
--- a/drivers/xen/grant-table.c
+++ b/drivers/xen/grant-table.c
@@
-int gnttab_resume(void)
+#ifdef CONFIG_HIBERNATE_CALLBACKS
+int gnttab_resume(void)
 {
        gnttab_request_version();
        return gnttab_setup();
@@
        if (xen_pv_domain())
                gnttab_interface->unmap_frames();
        return 0;
 }
+#endif
 
 static int gnttab_expand(unsigned int req_entries)
 {
diff --git a/include/xen/grant_table.h b/include/xen/grant_table.h
--- a/include/xen/grant_table.h
+++ b/include/xen/grant_table.h
@@
 
 int gnttab_init(void);
+#ifdef CONFIG_HIBERNATE_CALLBACKS
 int gnttab_suspend(void);
 int gnttab_resume(void);
+#else
+static inline int gnttab_suspend(void)
+{
+       return 0;
+}
+
+static inline int gnttab_resume(void)
+{
+       return 0;
+}
+#endif
 
 int gnttab_grant_foreign_access(domid_t domid, unsigned long frame,
                                int readonly);