[PATCH] DVB: Fix locking to prevent Oops on SMP systems

Fix locking to prevent Oops on SMP systems when starting/stopping dvb network
interfaces.

Signed-off-by: Ralph Metzler <rjkm@metzlerbros.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@brturbo.com.br>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 20 insertions, 11 deletions

diff --git a/drivers/media/dvb/dvb-core/dvb_net.c b/drivers/media/dvb/dvb-core/dvb_net.c
index 87935490bfb2..df536bd2e103 100644
--- a/drivers/media/dvb/dvb-core/dvb_net.c
+++ b/drivers/media/dvb/dvb-core/dvb_net.c
@@ -151,6 +151,8 @@ struct dvb_net_priv {
         unsigned char ule_bridged;              /* Whether the ULE_BRIDGED extension header was found. */
         int ule_sndu_remain;                    /* Nr. of bytes still required for current ULE SNDU. */
         unsigned long ts_count;                 /* Current ts cell counter. */
+
+        struct semaphore mutex;
 };
 
 
@@ -881,12 +883,13 @@ static int dvb_net_filter_sec_set(struct net_device *dev,
 
 static int dvb_net_feed_start(struct net_device *dev)
 {
-        int ret, i;
+        int ret = 0, i;
         struct dvb_net_priv *priv = dev->priv;
         struct dmx_demux *demux = priv->demux;
         unsigned char *mac = (unsigned char *) dev->dev_addr;
 
         dprintk("%s: rx_mode %i\n", __FUNCTION__, priv->rx_mode);
+        down(&priv->mutex);
         if (priv->tsfeed || priv->secfeed || priv->secfilter || priv->multi_secfilter[0])
                 printk("%s: BUG %d\n", __FUNCTION__, __LINE__);
 
@@ -900,7 +903,7 @@ static int dvb_net_feed_start(struct net_device *dev)
                                          dvb_net_sec_callback);
                 if (ret<0) {
                         printk("%s: could not allocate section feed\n", dev->name);
-                        return ret;
+                        goto error;
                 }
 
                 ret = priv->secfeed->set(priv->secfeed, priv->pid, 32768, 1);
@@ -909,7 +912,7 @@ static int dvb_net_feed_start(struct net_device *dev)
                         printk("%s: could not set section feed\n", dev->name);
                         priv->demux->release_section_feed(priv->demux, priv->secfeed);
                         priv->secfeed=NULL;
-                        return ret;
+                        goto error;
                 }
 
                 if (priv->rx_mode != RX_MODE_PROMISC) {
@@ -948,7 +951,7 @@ static int dvb_net_feed_start(struct net_device *dev)
                 ret = demux->allocate_ts_feed(demux, &priv->tsfeed, dvb_net_ts_callback);
                 if (ret < 0) {
                         printk("%s: could not allocate ts feed\n", dev->name);
-                        return ret;
+                        goto error;
                 }
 
                 /* Set netdevice pointer for ts decaps callback. */
@@ -962,23 +965,26 @@ static int dvb_net_feed_start(struct net_device *dev)
                         printk("%s: could not set ts feed\n", dev->name);
                         priv->demux->release_ts_feed(priv->demux, priv->tsfeed);
                         priv->tsfeed = NULL;
-                        return ret;
+                        goto error;
                 }
 
                 dprintk("%s: start filtering\n", __FUNCTION__);
                 priv->tsfeed->start_filtering(priv->tsfeed);
         } else
-                return -EINVAL;
+                ret = -EINVAL;
 
-        return 0;
+error:
+        up(&priv->mutex);
+        return ret;
 }
 
 static int dvb_net_feed_stop(struct net_device *dev)
 {
         struct dvb_net_priv *priv = dev->priv;
-        int i;
+        int i, ret = 0;
 
         dprintk("%s\n", __FUNCTION__);
+        down(&priv->mutex);
         if (priv->feedtype == DVB_NET_FEEDTYPE_MPE) {
                 if (priv->secfeed) {
                         if (priv->secfeed->is_filtering) {
@@ -1019,8 +1025,9 @@ static int dvb_net_feed_stop(struct net_device *dev)
                 else
                         printk("%s: no ts feed to stop\n", dev->name);
         } else
-                return -EINVAL;
-        return 0;
+                ret = -EINVAL;
+        up(&priv->mutex);
+        return ret;
 }
 
 
@@ -1044,8 +1051,8 @@ static void wq_set_multicast_list (void *data)
         struct dvb_net_priv *priv = dev->priv;
 
         dvb_net_feed_stop(dev);
-
         priv->rx_mode = RX_MODE_UNI;
+        spin_lock_bh(&dev->xmit_lock);
 
         if (dev->flags & IFF_PROMISC) {
                 dprintk("%s: promiscuous mode\n", dev->name);
@@ -1070,6 +1077,7 @@ static void wq_set_multicast_list (void *data)
                 }
         }
 
+        spin_unlock_bh(&dev->xmit_lock);
         dvb_net_feed_start(dev);
 }
 
@@ -1200,6 +1208,7 @@ static int dvb_net_add_if(struct dvb_net *dvbnet, u16 pid, u8 feedtype)
 
         INIT_WORK(&priv->set_multicast_list_wq, wq_set_multicast_list, net);
         INIT_WORK(&priv->restart_net_feed_wq, wq_restart_net_feed, net);
+        init_MUTEX(&priv->mutex);
 
         net->base_addr = pid;