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-rw-r--r--drivers/tty/n_gsm.c111
1 files changed, 91 insertions, 20 deletions
diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
index 9a13e51..a38114b 100644
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -133,6 +133,7 @@ struct gsm_dlci {
#define DLCI_OPENING 1 /* Sending SABM not seen UA */
#define DLCI_OPEN 2 /* SABM/UA complete */
#define DLCI_CLOSING 3 /* Sending DISC not seen UA/DM */
+ struct kref ref; /* freed from port or mux close */
struct mutex mutex;
/* Link layer */
@@ -194,6 +195,7 @@ struct gsm_mux {
struct tty_struct *tty; /* The tty our ldisc is bound to */
spinlock_t lock;
unsigned int num;
+ struct kref ref;
/* Events on the GSM channel */
wait_queue_head_t event;
@@ -1606,6 +1608,7 @@ static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr)
if (dlci == NULL)
return NULL;
spin_lock_init(&dlci->lock);
+ kref_init(&dlci->ref);
mutex_init(&dlci->mutex);
dlci->fifo = &dlci->_fifo;
if (kfifo_alloc(&dlci->_fifo, 4096, GFP_KERNEL) < 0) {
@@ -1632,26 +1635,52 @@ static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr)
}
/**
- * gsm_dlci_free - release DLCI
+ * gsm_dlci_free - free DLCI
+ * @dlci: DLCI to free
+ *
+ * Free up a DLCI.
+ *
+ * Can sleep.
+ */
+static void gsm_dlci_free(struct kref *ref)
+{
+ struct gsm_dlci *dlci = container_of(ref, struct gsm_dlci, ref);
+
+ del_timer_sync(&dlci->t1);
+ dlci->gsm->dlci[dlci->addr] = NULL;
+ kfifo_free(dlci->fifo);
+ while ((dlci->skb = skb_dequeue(&dlci->skb_list)))
+ kfree_skb(dlci->skb);
+ kfree(dlci);
+}
+
+static inline void dlci_get(struct gsm_dlci *dlci)
+{
+ kref_get(&dlci->ref);
+}
+
+static inline void dlci_put(struct gsm_dlci *dlci)
+{
+ kref_put(&dlci->ref, gsm_dlci_free);
+}
+
+/**
+ * gsm_dlci_release - release DLCI
* @dlci: DLCI to destroy
*
- * Free up a DLCI. Currently to keep the lifetime rules sane we only
- * clean up DLCI objects when the MUX closes rather than as the port
- * is closed down on both the tty and mux levels.
+ * Release a DLCI. Actual free is deferred until either
+ * mux is closed or tty is closed - whichever is last.
*
* Can sleep.
*/
-static void gsm_dlci_free(struct gsm_dlci *dlci)
+static void gsm_dlci_release(struct gsm_dlci *dlci)
{
struct tty_struct *tty = tty_port_tty_get(&dlci->port);
if (tty) {
tty_vhangup(tty);
tty_kref_put(tty);
}
- del_timer_sync(&dlci->t1);
- dlci->gsm->dlci[dlci->addr] = NULL;
- kfifo_free(dlci->fifo);
- kfree(dlci);
+ dlci_put(dlci);
}
/*
@@ -1989,7 +2018,7 @@ void gsm_cleanup_mux(struct gsm_mux *gsm)
/* Free up any link layer users */
for (i = 0; i < NUM_DLCI; i++)
if (gsm->dlci[i])
- gsm_dlci_free(gsm->dlci[i]);
+ gsm_dlci_release(gsm->dlci[i]);
/* Now wipe the queues */
for (txq = gsm->tx_head; txq != NULL; txq = gsm->tx_head) {
gsm->tx_head = txq->next;
@@ -2050,8 +2079,7 @@ EXPORT_SYMBOL_GPL(gsm_activate_mux);
* gsm_free_mux - free up a mux
* @mux: mux to free
*
- * Dispose of allocated resources for a dead mux. No refcounting
- * at present so the mux must be truly dead.
+ * Dispose of allocated resources for a dead mux
*/
void gsm_free_mux(struct gsm_mux *gsm)
{
@@ -2062,6 +2090,28 @@ void gsm_free_mux(struct gsm_mux *gsm)
EXPORT_SYMBOL_GPL(gsm_free_mux);
/**
+ * gsm_free_muxr - free up a mux
+ * @mux: mux to free
+ *
+ * Dispose of allocated resources for a dead mux
+ */
+static void gsm_free_muxr(struct kref *ref)
+{
+ struct gsm_mux *gsm = container_of(ref, struct gsm_mux, ref);
+ gsm_free_mux(gsm);
+}
+
+static inline void mux_get(struct gsm_mux *gsm)
+{
+ kref_get(&gsm->ref);
+}
+
+static inline void mux_put(struct gsm_mux *gsm)
+{
+ kref_put(&gsm->ref, gsm_free_muxr);
+}
+
+/**
* gsm_alloc_mux - allocate a mux
*
* Creates a new mux ready for activation.
@@ -2084,6 +2134,7 @@ struct gsm_mux *gsm_alloc_mux(void)
return NULL;
}
spin_lock_init(&gsm->lock);
+ kref_init(&gsm->ref);
gsm->t1 = T1;
gsm->t2 = T2;
@@ -2255,7 +2306,7 @@ static void gsmld_close(struct tty_struct *tty)
gsmld_flush_buffer(tty);
/* Do other clean up here */
- gsm_free_mux(gsm);
+ mux_put(gsm);
}
/**
@@ -2554,12 +2605,22 @@ static void net_free(struct kref *ref)
}
}
+static inline void muxnet_get(struct gsm_mux_net *mux_net)
+{
+ kref_get(&mux_net->ref);
+}
+
+static inline void muxnet_put(struct gsm_mux_net *mux_net)
+{
+ kref_put(&mux_net->ref, net_free);
+}
+
static int gsm_mux_net_start_xmit(struct sk_buff *skb,
struct net_device *net)
{
struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net);
struct gsm_dlci *dlci = mux_net->dlci;
- kref_get(&mux_net->ref);
+ muxnet_get(mux_net);
skb_queue_head(&dlci->skb_list, skb);
STATS(net).tx_packets++;
@@ -2567,7 +2628,7 @@ static int gsm_mux_net_start_xmit(struct sk_buff *skb,
gsm_dlci_data_kick(dlci);
/* And tell the kernel when the last transmit started. */
net->trans_start = jiffies;
- kref_put(&mux_net->ref, net_free);
+ muxnet_put(mux_net);
return NETDEV_TX_OK;
}
@@ -2587,14 +2648,14 @@ static void gsm_mux_rx_netchar(struct gsm_dlci *dlci,
struct net_device *net = dlci->net;
struct sk_buff *skb;
struct gsm_mux_net *mux_net = (struct gsm_mux_net *)netdev_priv(net);
- kref_get(&mux_net->ref);
+ muxnet_get(mux_net);
/* Allocate an sk_buff */
skb = dev_alloc_skb(size + NET_IP_ALIGN);
if (!skb) {
/* We got no receive buffer. */
STATS(net).rx_dropped++;
- kref_put(&mux_net->ref, net_free);
+ muxnet_put(mux_net);
return;
}
skb_reserve(skb, NET_IP_ALIGN);
@@ -2609,7 +2670,7 @@ static void gsm_mux_rx_netchar(struct gsm_dlci *dlci,
/* update out statistics */
STATS(net).rx_packets++;
STATS(net).rx_bytes += size;
- kref_put(&mux_net->ref, net_free);
+ muxnet_put(mux_net);
return;
}
@@ -2652,7 +2713,7 @@ static void gsm_destroy_network(struct gsm_dlci *dlci)
if (!dlci->net)
return;
mux_net = (struct gsm_mux_net *)netdev_priv(dlci->net);
- kref_put(&mux_net->ref, net_free);
+ muxnet_put(mux_net);
}
@@ -2814,6 +2875,9 @@ static int gsmtty_open(struct tty_struct *tty, struct file *filp)
port = &dlci->port;
port->count++;
tty->driver_data = dlci;
+ dlci_get(dlci);
+ dlci_get(dlci->gsm->dlci[0]);
+ mux_get(dlci->gsm);
tty_port_tty_set(port, tty);
dlci->modem_rx = 0;
@@ -2829,16 +2893,23 @@ static int gsmtty_open(struct tty_struct *tty, struct file *filp)
static void gsmtty_close(struct tty_struct *tty, struct file *filp)
{
struct gsm_dlci *dlci = tty->driver_data;
+ struct gsm_mux *gsm;
+
if (dlci == NULL)
return;
mutex_lock(&dlci->mutex);
gsm_destroy_network(dlci);
mutex_unlock(&dlci->mutex);
+ gsm = dlci->gsm;
if (tty_port_close_start(&dlci->port, tty, filp) == 0)
- return;
+ goto out;
gsm_dlci_begin_close(dlci);
tty_port_close_end(&dlci->port, tty);
tty_port_tty_set(&dlci->port, NULL);
+out:
+ dlci_put(dlci);
+ dlci_put(gsm->dlci[0]);
+ mux_put(gsm);
}
static void gsmtty_hangup(struct tty_struct *tty)
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