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/fs/jbd/journal.c b/fs/jbd/journal.c
index 65c2904..5d9fec0 100644
--- a/fs/jbd/journal.c
+++ b/fs/jbd/journal.c
@@ -217,7 +217,7 @@
 	if (IS_ERR(t))
 		return PTR_ERR(t);
 
-	wait_event(journal->j_wait_done_commit, journal->j_task != 0);
+	wait_event(journal->j_wait_done_commit, journal->j_task != NULL);
 	return 0;
 }
 
@@ -229,7 +229,8 @@
 	while (journal->j_task) {
 		wake_up(&journal->j_wait_commit);
 		spin_unlock(&journal->j_state_lock);
-		wait_event(journal->j_wait_done_commit, journal->j_task == 0);
+		wait_event(journal->j_wait_done_commit,
+				journal->j_task == NULL);
 		spin_lock(&journal->j_state_lock);
 	}
 	spin_unlock(&journal->j_state_lock);
@@ -1651,14 +1652,14 @@
 	atomic_inc(&nr_journal_heads);
 #endif
 	ret = kmem_cache_alloc(journal_head_cache, GFP_NOFS);
-	if (ret == 0) {
+	if (ret == NULL) {
 		jbd_debug(1, "out of memory for journal_head\n");
 		if (time_after(jiffies, last_warning + 5*HZ)) {
 			printk(KERN_NOTICE "ENOMEM in %s, retrying.\n",
 			       __FUNCTION__);
 			last_warning = jiffies;
 		}
-		while (ret == 0) {
+		while (ret == NULL) {
 			yield();
 			ret = kmem_cache_alloc(journal_head_cache, GFP_NOFS);
 		}