vfs: fix coding style at dcache.c.

Index: b/fs/dcache.c
===================================================================
@@ -453,15 +453,15 @@ static void __shrink_dcache_sb(struct su
 	int cnt = 0;
 
 	BUG_ON(!sb);
-	BUG_ON((flags & DCACHE_REFERENCED) && count == NULL);
+	BUG_ON((flags & DCACHE_REFERENCED) && !count);
 	spin_lock(&dcache_lock);
-	if (count != NULL)
+	if (count)
 		/* called from prune_dcache() and shrink_dcache_parent() */
 		cnt = *count;
 restart:
-	if (count == NULL)
+	if (!count) {
 		list_splice_init(&sb->s_dentry_lru, &tmp);
-	else {
+	} else {
 		while (!list_empty(&sb->s_dentry_lru)) {
 			dentry = list_entry(sb->s_dentry_lru.prev,
 					struct dentry, d_lru);

@@ -473,16 +473,15 @@ restart:
 			 * the dentry has this flag set, don't free it. Clear
 			 * the flag and put it back on the LRU.
 			 */
-			if ((flags & DCACHE_REFERENCED)
-				&& (dentry->d_flags & DCACHE_REFERENCED)) {
+			if ((flags & DCACHE_REFERENCED) &&
+			    (dentry->d_flags & DCACHE_REFERENCED)) {
 				dentry->d_flags &= ~DCACHE_REFERENCED;
 				list_move_tail(&dentry->d_lru, &referenced);
 				spin_unlock(&dentry->d_lock);
 			} else {
 				list_move_tail(&dentry->d_lru, &tmp);
 				spin_unlock(&dentry->d_lock);
-				cnt--;
-				if (!cnt)
+				if (--cnt == 0)
 					break;
 			}
 		}

@@ -504,10 +503,10 @@ restart:
 		/* dentry->d_lock was dropped in prune_one_dentry() */
 		cond_resched_lock(&dcache_lock);
 	}
-	if (count == NULL && !list_empty(&sb->s_dentry_lru))
-		goto restart;
-	if (count != NULL)
+	if (count)
 		*count = cnt;
+	else if (!list_empty(&sb->s_dentry_lru))
+		goto restart;
 	if (!list_empty(&referenced))
 		list_splice(&referenced, &sb->s_dentry_lru);
 	spin_unlock(&dcache_lock);