From: Andrey Shvetsov <andrey.shvetsov@xxxxxx>
This introduces the kref for the net_dev_context to prevent the
destruction of the network devices that are in use.
Each get_net_dev_context is completed with the put_net_dev_context,
except the function aim_probe_channel that calls one more
get_net_dev_context or kref_get and the function aim_disconnect_channel
that calls one more put_net_dev_context.
Signed-off-by: Andrey Shvetsov <andrey.shvetsov@xxxxxx>
Signed-off-by: Christian Gromm <christian.gromm@xxxxxxxxxxxxx>
---
drivers/staging/most/aim-network/networking.c | 92 +++++++++++++++++++++------
1 file changed, 72 insertions(+), 20 deletions(-)
diff --git a/drivers/staging/most/aim-network/networking.c b/drivers/staging/most/aim-network/networking.c
index cbd9500..8cf1c81 100644
--- a/drivers/staging/most/aim-network/networking.c
+++ b/drivers/staging/most/aim-network/networking.c
@@ -21,6 +21,7 @@
#include <linux/list.h>
#include <linux/wait.h>
#include <linux/kobject.h>
+#include <linux/kref.h>
#include "mostcore.h"
#define MEP_HDR_LEN 8
@@ -69,6 +70,7 @@ struct net_dev_context {
struct net_dev_channel rx;
struct net_dev_channel tx;
struct list_head list;
+ struct kref kref;
};
static struct list_head net_devices = LIST_HEAD_INIT(net_devices);
@@ -268,6 +270,26 @@ static void most_nd_setup(struct net_device *dev)
dev->netdev_ops = &most_nd_ops;
}
+static void release_nd(struct kref *kref)
+{
+ struct net_dev_context *nd;
+
+ nd = container_of(kref, struct net_dev_context, kref);
+ list_del(&nd->list);
+}
+
+static inline void put_net_dev_context(struct net_dev_context *nd)
+{
+ unsigned long flags;
+ int released;
+
+ spin_lock_irqsave(&list_lock, flags);
+ released = kref_put(&nd->kref, release_nd);
+ spin_unlock_irqrestore(&list_lock, flags);
+ if (released)
+ free_netdev(nd->dev);
+}
+
static struct net_dev_context *get_net_dev_context(
struct most_interface *iface)
{
@@ -277,6 +299,7 @@ static struct net_dev_context *get_net_dev_context(
spin_lock_irqsave(&list_lock, flags);
list_for_each_entry(nd, &net_devices, list) {
if (nd->iface == iface) {
+ kref_get(&nd->kref);
spin_unlock_irqrestore(&list_lock, flags);
return nd;
}
@@ -300,7 +323,6 @@ static int aim_probe_channel(struct most_interface *iface, int channel_idx,
return -EINVAL;
nd = get_net_dev_context(iface);
-
if (!nd) {
struct net_device *dev;
@@ -309,19 +331,34 @@ static int aim_probe_channel(struct most_interface *iface, int channel_idx,
if (!dev)
return -ENOMEM;
+ /*
+ * The network device for the given iface may be added with use
+ * of the other channel just after the get_net_dev_context
+ * call. Free our duplicate of net_device in this case.
+ */
+ spin_lock_irqsave(&list_lock, flags);
+ list_for_each_entry(nd, &net_devices, list) {
+ if (nd->iface == iface) {
+ kref_get(&nd->kref);
+ spin_unlock_irqrestore(&list_lock, flags);
+ free_netdev(dev);
+ goto ok;
+ }
+ }
+
nd = netdev_priv(dev);
+ kref_init(&nd->kref);
nd->iface = iface;
nd->dev = dev;
-
- spin_lock_irqsave(&list_lock, flags);
list_add(&nd->list, &net_devices);
spin_unlock_irqrestore(&list_lock, flags);
}
+ok:
ch = ccfg->direction == MOST_CH_TX ? &nd->tx : &nd->rx;
if (ch->linked) {
pr_err("only one channel per instance & direction allowed\n");
- return -EINVAL;
+ goto err;
}
ch->ch_id = channel_idx;
@@ -329,10 +366,14 @@ static int aim_probe_channel(struct most_interface *iface, int channel_idx,
if (nd->tx.linked && nd->rx.linked && register_netdev(nd->dev)) {
pr_err("register_netdev() failed\n");
ch->linked = false;
- return -EINVAL;
+ goto err;
}
return 0;
+
+err:
+ put_net_dev_context(nd);
+ return -EINVAL;
}
static int aim_disconnect_channel(struct most_interface *iface,
@@ -340,7 +381,7 @@ static int aim_disconnect_channel(struct most_interface *iface,
{
struct net_dev_context *nd;
struct net_dev_channel *ch;
- unsigned long flags;
+ int ret = -EINVAL;
nd = get_net_dev_context(iface);
if (!nd)
@@ -351,7 +392,7 @@ static int aim_disconnect_channel(struct most_interface *iface,
else if (nd->tx.linked && channel_idx == nd->tx.ch_id)
ch = &nd->tx;
else
- return -EINVAL;
+ goto put_nd;
/*
* do not call most_stop_channel() here, because channels are
@@ -361,14 +402,12 @@ static int aim_disconnect_channel(struct most_interface *iface,
unregister_netdev(nd->dev);
ch->linked = false;
- if (!nd->rx.linked && !nd->tx.linked) {
- spin_lock_irqsave(&list_lock, flags);
- list_del(&nd->list);
- spin_unlock_irqrestore(&list_lock, flags);
- free_netdev(nd->dev);
- }
+ put_net_dev_context(nd);
+ ret = 0;
- return 0;
+put_nd:
+ put_net_dev_context(nd);
+ return ret;
}
static int aim_resume_tx_channel(struct most_interface *iface,
@@ -377,10 +416,13 @@ static int aim_resume_tx_channel(struct most_interface *iface,
struct net_dev_context *nd;
nd = get_net_dev_context(iface);
- if (!nd || nd->tx.ch_id != channel_idx)
+ if (!nd)
return 0;
- netif_wake_queue(nd->dev);
+ if (nd->tx.ch_id == channel_idx)
+ netif_wake_queue(nd->dev);
+
+ put_net_dev_context(nd);
return 0;
}
@@ -393,25 +435,30 @@ static int aim_rx_data(struct mbo *mbo)
struct sk_buff *skb;
struct net_device *dev;
unsigned int skb_len;
+ int ret = -EIO;
nd = get_net_dev_context(mbo->ifp);
- if (!nd || nd->rx.ch_id != mbo->hdm_channel_id)
+ if (!nd)
return -EIO;
+ if (nd->rx.ch_id != mbo->hdm_channel_id)
+ goto put_nd;
+
dev = nd->dev;
if (nd->is_mamac) {
if (!PMS_IS_MAMAC(buf, len))
- return -EIO;
+ goto put_nd;
skb = dev_alloc_skb(len - MDP_HDR_LEN + 2 * ETH_ALEN + 2);
} else {
if (!PMS_IS_MEP(buf, len))
- return -EIO;
+ goto put_nd;
skb = dev_alloc_skb(len - MEP_HDR_LEN);
}
+ ret = 0;
if (!skb) {
dev->stats.rx_dropped++;
pr_err_once("drop packet: no memory for skb\n");
@@ -450,7 +497,10 @@ static int aim_rx_data(struct mbo *mbo)
out:
most_put_mbo(mbo);
- return 0;
+
+put_nd:
+ put_net_dev_context(nd);
+ return ret;
}
static struct most_aim aim = {
@@ -509,6 +559,8 @@ static void on_netinfo(struct most_interface *iface,
m[0], m[1], m[2], m[3], m[4], m[5]);
}
}
+
+ put_net_dev_context(nd);
}
module_init(most_net_init);
--
1.9.1
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