2019-08-02 23:31:24

by Chuhong Yuan

Subject: [PATCH] niu: 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.

Also convert refcount from 0-based to 1-based.

Signed-off-by: Chuhong Yuan <[email protected]>
---
drivers/net/ethernet/sun/niu.c | 6 +++---
drivers/net/ethernet/sun/niu.h | 2 +-
2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/sun/niu.c b/drivers/net/ethernet/sun/niu.c
index 0bc5863bffeb..5bf096e51db7 100644
--- a/drivers/net/ethernet/sun/niu.c
+++ b/drivers/net/ethernet/sun/niu.c
@@ -9464,7 +9464,7 @@ static struct niu_parent *niu_new_parent(struct niu *np,
memcpy(&p->id, id, sizeof(*id));
p->plat_type = ptype;
INIT_LIST_HEAD(&p->list);
- atomic_set(&p->refcnt, 0);
+ refcount_set(&p->refcnt, 1);
list_add(&p->list, &niu_parent_list);
spin_lock_init(&p->lock);

@@ -9524,7 +9524,7 @@ static struct niu_parent *niu_get_parent(struct niu *np,
port_name);
if (!err) {
p->ports[port] = np;
- atomic_inc(&p->refcnt);
+ refcount_inc(&p->refcnt);
}
}
mutex_unlock(&niu_parent_lock);
@@ -9552,7 +9552,7 @@ static void niu_put_parent(struct niu *np)
p->ports[port] = NULL;
np->parent = NULL;

- if (atomic_dec_and_test(&p->refcnt)) {
+ if (refcount_dec_and_test(&p->refcnt)) {
list_del(&p->list);
platform_device_unregister(p->plat_dev);
}
diff --git a/drivers/net/ethernet/sun/niu.h b/drivers/net/ethernet/sun/niu.h
index 04c215f91fc0..755e6dd4c903 100644
--- a/drivers/net/ethernet/sun/niu.h
+++ b/drivers/net/ethernet/sun/niu.h
@@ -3071,7 +3071,7 @@ struct niu_parent {

struct niu *ports[NIU_MAX_PORTS];

- atomic_t refcnt;
+ refcount_t refcnt;
struct list_head list;

spinlock_t lock;
--
2.20.1

2019-08-03 15:15:15

by Chuhong Yuan

Subject: Re: [PATCH] niu: Use refcount_t for refcount

Chuhong Yuan <[email protected]> 于2019年8月2日周五 下午8:57写道：
>
> refcount_t is better for reference counters since its
> implementation can prevent overflows.
> So convert atomic_t ref counters to refcount_t.
>
> Also convert refcount from 0-based to 1-based.

It seems that directly converting refcount from 0-based to
1-based is infeasible.
I am sorry for this mistake.

Regards,
Chuhong

>
> Signed-off-by: Chuhong Yuan <[email protected]>
> ---
> drivers/net/ethernet/sun/niu.c | 6 +++---
> drivers/net/ethernet/sun/niu.h | 2 +-
> 2 files changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/net/ethernet/sun/niu.c b/drivers/net/ethernet/sun/niu.c
> index 0bc5863bffeb..5bf096e51db7 100644
> --- a/drivers/net/ethernet/sun/niu.c
> +++ b/drivers/net/ethernet/sun/niu.c
> @@ -9464,7 +9464,7 @@ static struct niu_parent *niu_new_parent(struct niu *np,
> memcpy(&p->id, id, sizeof(*id));
> p->plat_type = ptype;
> INIT_LIST_HEAD(&p->list);
> - atomic_set(&p->refcnt, 0);
> + refcount_set(&p->refcnt, 1);
> list_add(&p->list, &niu_parent_list);
> spin_lock_init(&p->lock);
>
> @@ -9524,7 +9524,7 @@ static struct niu_parent *niu_get_parent(struct niu *np,
> port_name);
> if (!err) {
> p->ports[port] = np;
> - atomic_inc(&p->refcnt);
> + refcount_inc(&p->refcnt);
> }
> }
> mutex_unlock(&niu_parent_lock);
> @@ -9552,7 +9552,7 @@ static void niu_put_parent(struct niu *np)
> p->ports[port] = NULL;
> np->parent = NULL;
>
> - if (atomic_dec_and_test(&p->refcnt)) {
> + if (refcount_dec_and_test(&p->refcnt)) {
> list_del(&p->list);
> platform_device_unregister(p->plat_dev);
> }
> diff --git a/drivers/net/ethernet/sun/niu.h b/drivers/net/ethernet/sun/niu.h
> index 04c215f91fc0..755e6dd4c903 100644
> --- a/drivers/net/ethernet/sun/niu.h
> +++ b/drivers/net/ethernet/sun/niu.h
> @@ -3071,7 +3071,7 @@ struct niu_parent {
>
> struct niu *ports[NIU_MAX_PORTS];
>
> - atomic_t refcnt;
> + refcount_t refcnt;
> struct list_head list;
>
> spinlock_t lock;
> --
> 2.20.1
>