mm, hugetlb: remove hugetlb_zero and hugetlb_infinity

They are unnecessary: "zero" can be used in place of "hugetlb_zero" and
passing extra2 == NULL is equivalent to infinity.
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reviewed-by: Luiz Capitulino <lcapitulino@redhat.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/hugetlb.h

@@ -87,7 +87,6 @@ pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud);
 #endif
 
 extern unsigned long hugepages_treat_as_movable;
-extern const unsigned long hugetlb_zero, hugetlb_infinity;
 extern int sysctl_hugetlb_shm_group;
 extern struct list_head huge_boot_pages;
 

kernel/sysctl.c

@@ -1240,8 +1240,7 @@ static struct ctl_table vm_table[] = {
 		.maxlen		= sizeof(unsigned long),
 		.mode		= 0644,
 		.proc_handler	= hugetlb_sysctl_handler,
-		.extra1		= (void *)&hugetlb_zero,
-		.extra2		= (void *)&hugetlb_infinity,
+		.extra1		= &zero,
 	},
 #ifdef CONFIG_NUMA
 	{
@@ -1250,8 +1249,7 @@ static struct ctl_table vm_table[] = {
 		.maxlen         = sizeof(unsigned long),
 		.mode           = 0644,
 		.proc_handler   = &hugetlb_mempolicy_sysctl_handler,
-		.extra1		= (void *)&hugetlb_zero,
-		.extra2		= (void *)&hugetlb_infinity,
+		.extra1		= &zero,
 	},
 #endif
 	 {
@@ -1274,8 +1272,7 @@ static struct ctl_table vm_table[] = {
 		.maxlen		= sizeof(unsigned long),
 		.mode		= 0644,
 		.proc_handler	= hugetlb_overcommit_handler,
-		.extra1		= (void *)&hugetlb_zero,
-		.extra2		= (void *)&hugetlb_infinity,
+		.extra1		= &zero,
 	},
 #endif
 	{

mm/hugetlb.c

@@ -35,7 +35,6 @@
 #include <linux/node.h>
 #include "internal.h"
 
-const unsigned long hugetlb_zero = 0, hugetlb_infinity = ~0UL;
 unsigned long hugepages_treat_as_movable;
 
 int hugetlb_max_hstate __read_mostly;