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Subject[PATCH v2 23/41] CAPI: Use kref on capiminor
Date
Install a reference counter for capiminor objects. Acquire it when
obtaining a capiminor from the array during capinc_tty_open, drop it
when closing the tty again. Another reference is held for the hook-up
with capincci.

Signed-off-by: Jan Kiszka <jan.kiszka@web.de>
---
drivers/isdn/capi/capi.c | 37 ++++++++++++++++++++++++++++---------
1 files changed, 28 insertions(+), 9 deletions(-)
diff --git a/drivers/isdn/capi/capi.c b/drivers/isdn/capi/capi.c
index b1de0cb..732cdb5 100644
--- a/drivers/isdn/capi/capi.c
+++ b/drivers/isdn/capi/capi.c
@@ -83,6 +83,8 @@ struct datahandle_queue {
};

struct capiminor {
+ struct kref kref;
+
struct capincci *nccip;
unsigned int minor;
struct dentry *capifs_dentry;
@@ -223,6 +225,8 @@ static struct capiminor *capiminor_alloc(struct capi20_appl *ap, u32 ncci)
return NULL;
}

+ kref_init(&mp->kref);
+
mp->ap = ap;
mp->ncci = ncci;
mp->msgid = 0;
@@ -265,18 +269,11 @@ err_out1:
return NULL;
}

-static void capiminor_free(struct capiminor *mp)
+static void capiminor_destroy(struct kref *kref)
{
- unsigned long flags;
-
- tty_unregister_device(capinc_tty_driver, mp->minor);
-
- write_lock_irqsave(&capiminors_lock, flags);
- capiminors[mp->minor] = NULL;
- write_unlock_irqrestore(&capiminors_lock, flags);
+ struct capiminor *mp = container_of(kref, struct capiminor, kref);

kfree_skb(mp->ttyskb);
- mp->ttyskb = NULL;
skb_queue_purge(&mp->inqueue);
skb_queue_purge(&mp->outqueue);
capiminor_del_all_ack(mp);
@@ -289,11 +286,31 @@ static struct capiminor *capiminor_get(unsigned int minor)

read_lock(&capiminors_lock);
mp = capiminors[minor];
+ if (mp)
+ kref_get(&mp->kref);
read_unlock(&capiminors_lock);

return mp;
}

+static inline void capiminor_put(struct capiminor *mp)
+{
+ kref_put(&mp->kref, capiminor_destroy);
+}
+
+static void capiminor_free(struct capiminor *mp)
+{
+ unsigned long flags;
+
+ tty_unregister_device(capinc_tty_driver, mp->minor);
+
+ write_lock_irqsave(&capiminors_lock, flags);
+ capiminors[mp->minor] = NULL;
+ write_unlock_irqrestore(&capiminors_lock, flags);
+
+ capiminor_put(mp);
+}
+
/* -------- struct capincci ----------------------------------------- */

static void capincci_alloc_minor(struct capidev *cdev, struct capincci *np)
@@ -1029,6 +1046,8 @@ static void capinc_tty_close(struct tty_struct * tty, struct file * file)
#endif
if (mp->nccip == NULL)
capiminor_free(mp);
+
+ capiminor_put(mp);
}

#ifdef _DEBUG_REFCOUNT
--
1.6.0.2


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