fs:cifs: convert from atomic_t to refcount_t on tlink->tl_count

use refcount_t instead of atomic_t
which prevents reference counter overflows.

Reported-by: Zeal Robot <zealci@zte.com.cm>
Signed-off-by: chiminghao <chi.minghao@zte.com.cn>

fs/cifs/cifsglob.h

@@ -8,7 +8,7 @@
  */
 #ifndef _CIFS_GLOB_H
 #define _CIFS_GLOB_H
-
+#include <linux/refcount.h>
 #include <linux/in.h>
 #include <linux/in6.h>
 #include <linux/inet.h>
@@ -1128,7 +1128,7 @@ struct tcon_link {
 #define TCON_LINK_PENDING	1
 #define TCON_LINK_IN_TREE	2
 	unsigned long		tl_time;
-	atomic_t		tl_count;
+	refcount_t		tl_count;
 	struct cifs_tcon	*tl_tcon;
 };
 

fs/cifs/connect.c

@@ -2362,7 +2362,7 @@ cifs_put_tlink(struct tcon_link *tlink)
 	if (!tlink || IS_ERR(tlink))
 		return;
 
-	if (!atomic_dec_and_test(&tlink->tl_count) ||
+	if (!refcount_dec_and_test(&tlink->tl_count) ||
 	    test_bit(TCON_LINK_IN_TREE, &tlink->tl_flags)) {
 		tlink->tl_time = jiffies;
 		return;