sparse pointer use of zero as null

Get rid of sparse related warnings from places that use integer as NULL
pointer.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Cc: Andi Kleen <ak@suse.de>
Cc: Jeff Garzik <jeff@garzik.org>
Cc: Matt Mackall <mpm@selenic.com>
Cc: Ian Kent <raven@themaw.net>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Davide Libenzi <davidel@xmailserver.org>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index ae2959b..034617f 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1020,7 +1020,7 @@
 	 * size such that we can guarentee to record the reservation. */
 	if (&rg->link == head || t < rg->from) {
 		nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
-		if (nrg == 0)
+		if (!nrg)
 			return -ENOMEM;
 		nrg->from = f;
 		nrg->to   = f;
diff --git a/mm/mremap.c b/mm/mremap.c
index 8ea5c24..08e3c7f 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -291,7 +291,7 @@
 		if ((addr <= new_addr) && (addr+old_len) > new_addr)
 			goto out;
 
-		ret = security_file_mmap(0, 0, 0, 0, new_addr, 1);
+		ret = security_file_mmap(NULL, 0, 0, 0, new_addr, 1);
 		if (ret)
 			goto out;
 
@@ -399,7 +399,7 @@
 				goto out;
 			}
 
-			ret = security_file_mmap(0, 0, 0, 0, new_addr, 1);
+			ret = security_file_mmap(NULL, 0, 0, 0, new_addr, 1);
 			if (ret)
 				goto out;
 		}
diff --git a/mm/vmscan.c b/mm/vmscan.c
index e147138..cb474cc 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1282,7 +1282,7 @@
 	 */
 	if (priority < 0)
 		priority = 0;
-	for (i = 0; zones[i] != 0; i++) {
+	for (i = 0; zones[i] != NULL; i++) {
 		struct zone *zone = zones[i];
 
 		if (!cpuset_zone_allowed_hardwall(zone, GFP_KERNEL))