mkiss: Use refcount_t for refcount

refcount_t is better for reference counters since its
implementation can prevent overflows.
So convert atomic_t ref counters to refcount_t.

Signed-off-by: Chuhong Yuan <hslester96@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/hamradio/mkiss.c b/drivers/net/hamradio/mkiss.c
index 442018c..c5bfa19 100644 (file)
--- a/drivers/net/hamradio/mkiss.c
+++ b/drivers/net/hamradio/mkiss.c
@@ -25,6 +25,7 @@
 #include <linux/skbuff.h>
 #include <linux/if_arp.h>
 #include <linux/jiffies.h>
+#include <linux/refcount.h>
 
 #include <net/ax25.h>
 
@@ -70,7 +71,7 @@ struct mkiss {
 #define CRC_MODE_FLEX_TEST     3
 #define CRC_MODE_SMACK_TEST    4
 
-       atomic_t                refcnt;
+       refcount_t              refcnt;
        struct completion       dead;
 };
 
@@ -668,7 +669,7 @@ static struct mkiss *mkiss_get(struct tty_struct *tty)
        read_lock(&disc_data_lock);
        ax = tty->disc_data;
        if (ax)
-               atomic_inc(&ax->refcnt);
+               refcount_inc(&ax->refcnt);
        read_unlock(&disc_data_lock);
 
        return ax;
@@ -676,7 +677,7 @@ static struct mkiss *mkiss_get(struct tty_struct *tty)
 
 static void mkiss_put(struct mkiss *ax)
 {
-       if (atomic_dec_and_test(&ax->refcnt))
+       if (refcount_dec_and_test(&ax->refcnt))
                complete(&ax->dead);
 }
 
@@ -704,7 +705,7 @@ static int mkiss_open(struct tty_struct *tty)
        ax->dev = dev;
 
        spin_lock_init(&ax->buflock);
-       atomic_set(&ax->refcnt, 1);
+       refcount_set(&ax->refcnt, 1);
        init_completion(&ax->dead);
 
        ax->tty = tty;
@@ -784,7 +785,7 @@ static void mkiss_close(struct tty_struct *tty)
         * We have now ensured that nobody can start using ap from now on, but
         * we have to wait for all existing users to finish.
         */
-       if (!atomic_dec_and_test(&ax->refcnt))
+       if (!refcount_dec_and_test(&ax->refcnt))
                wait_for_completion(&ax->dead);
        /*
         * Halt the transmit queue so that a new transmit cannot scribble