ocfs2: change slot number type s16 to u16

Dan Carpenter reported the following static checker warning.

	fs/ocfs2/super.c:1269 ocfs2_parse_options() warn: '(-1)' 65535 can't fit into 32767 'mopt->slot'
	fs/ocfs2/suballoc.c:859 ocfs2_init_inode_steal_slot() warn: '(-1)' 65535 can't fit into 32767 'osb->s_inode_steal_slot'
	fs/ocfs2/suballoc.c:867 ocfs2_init_meta_steal_slot() warn: '(-1)' 65535 can't fit into 32767 'osb->s_meta_steal_slot'

That's because OCFS2_INVALID_SLOT is (u16)-1. Slot number in ocfs2 can be
never negative, so change s16 to u16.

Fixes: 9277f833 ("ocfs2: fix value of OCFS2_INVALID_SLOT")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Junxiao Bi <junxiao.bi@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: Gang He <ghe@suse.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Jun Piao <piaojun@huawei.com>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/20200627001259.19757-1-junxiao.bi@oracle.comSigned-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/ocfs2/ocfs2.h

@@ -327,8 +327,8 @@ struct ocfs2_super
 	spinlock_t osb_lock;
 	u32 s_next_generation;
 	unsigned long osb_flags;
-	s16 s_inode_steal_slot;
-	s16 s_meta_steal_slot;
+	u16 s_inode_steal_slot;
+	u16 s_meta_steal_slot;
 	atomic_t s_num_inodes_stolen;
 	atomic_t s_num_meta_stolen;
 

fs/ocfs2/suballoc.c

@@ -879,9 +879,9 @@ static void __ocfs2_set_steal_slot(struct ocfs2_super *osb, int slot, int type)
 {
 	spin_lock(&osb->osb_lock);
 	if (type == INODE_ALLOC_SYSTEM_INODE)
-		osb->s_inode_steal_slot = slot;
+		osb->s_inode_steal_slot = (u16)slot;
 	else if (type == EXTENT_ALLOC_SYSTEM_INODE)
-		osb->s_meta_steal_slot = slot;
+		osb->s_meta_steal_slot = (u16)slot;
 	spin_unlock(&osb->osb_lock);
 }
 

fs/ocfs2/super.c

@@ -78,7 +78,7 @@ struct mount_options
 	unsigned long	commit_interval;
 	unsigned long	mount_opt;
 	unsigned int	atime_quantum;
-	signed short	slot;
+	unsigned short	slot;
 	int		localalloc_opt;
 	unsigned int	resv_level;
 	int		dir_resv_level;
@@ -1349,7 +1349,7 @@ static int ocfs2_parse_options(struct super_block *sb,
 				goto bail;
 			}
 			if (option)
-				mopt->slot = (s16)option;
+				mopt->slot = (u16)option;
 			break;
 		case Opt_commit:
 			if (match_int(&args[0], &option)) {