Update global_page_state() support for 2.6.29 kernels.

Basically everything we need to monitor the global memory state of
the system is now cleanly available via global_page_state().  The
problem is that this interface is still fairly recent, and there
has been one change in the page state enum which we need to handle.
These changes basically boil down to the following:
- If global_page_state() is available we should use it.  Several
  autoconf checks have been added to detect the correct enum names.
- If global_page_state() is not available check to see if
  get_zone_counts() symbol is available and use that.
- If the get_zone_counts() symbol is not exported we have no choice
  be to dynamically aquire it at load time.  This is an absolute
  last resort for old kernel which we don't want to patch to
  cleanly export the symbol.

1 files changed, 10 insertions, 11 deletions

diff --git a/include/sys/vmsystm.h b/include/sys/vmsystm.h
index 75365fde0..1c367d7cd 100644
--- a/include/sys/vmsystm.h
+++ b/include/sys/vmsystm.h
@@ -123,22 +123,21 @@ extern struct pglist_data *pgdat_list_addr;
 #endif /* HAVE_PGDAT_HELPERS */
 
 /* Source linux/mm/vmstat.c */
-#ifndef HAVE_ZONE_STAT_ITEM_FIA
-# ifndef HAVE_GET_ZONE_COUNTS
+#if defined(NEED_GET_ZONE_COUNTS) && !defined(HAVE_GET_ZONE_COUNTS)
 typedef void (*get_zone_counts_t)(unsigned long *, unsigned long *,
 				  unsigned long *);
 extern get_zone_counts_t get_zone_counts_fn;
 # define get_zone_counts(a,i,f)	get_zone_counts_fn(a,i,f)
-# endif /* HAVE_GET_ZONE_COUNTS */
+#endif /* NEED_GET_ZONE_COUNTS && !HAVE_GET_ZONE_COUNTS */
 
-extern unsigned long spl_global_page_state(int);
-/* Defines designed to simulate enum but large enough to ensure no overlap */
-# define NR_FREE_PAGES		0x8001
-# define NR_INACTIVE		0x8002
-# define NR_ACTIVE		0x8003
-#else
-#define spl_global_page_state(item)	global_page_state(item)
-#endif /* HAVE_ZONE_STAT_ITEM_FIA */
+typedef enum spl_zone_stat_item {
+	SPL_NR_FREE_PAGES,
+	SPL_NR_INACTIVE,
+	SPL_NR_ACTIVE,
+	SPL_NR_ZONE_STAT_ITEMS
+} spl_zone_stat_item_t;
+
+extern unsigned long spl_global_page_state(spl_zone_stat_item_t);
 
 #define xcopyin(from, to, size)		copy_from_user(to, from, size)
 #define xcopyout(from, to, size)	copy_to_user(to, from, size)