2019-08-03 15:54:51

by Chuhong Yuan

Subject: [PATCH v2] 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 <[email protected]>
---
Changes in v2:
- Add #include.

drivers/net/hamradio/mkiss.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/drivers/net/hamradio/mkiss.c b/drivers/net/hamradio/mkiss.c
index 442018ccd65e..c5bfa19ddb93 100644
--- 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
--
2.20.1

2019-08-09 01:01:13

by David Miller

Subject: Re: [PATCH v2] mkiss: Use refcount_t for refcount

From: Chuhong Yuan <[email protected]>
Date: Sat, 3 Aug 2019 00:48:21 +0800

> 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 <[email protected]>
> ---
> Changes in v2:
> - Add #include.

Applied to net-next.