staging/cx25721: serialize access to devlist

index 160f669..ebdba7c 100644
@@ -770,10 +770,12 @@ static int cx25821_alsa_init(void)
 	struct cx25821_dev *dev = NULL;
 	struct list_head *list;
 
+	mutex_lock(&cx25821_devlist_mutex);
 	list_for_each(list, &cx25821_devlist) {
 		dev = list_entry(list, struct cx25821_dev, devlist);
 		cx25821_audio_initdev(dev);
 	}
+	mutex_unlock(&cx25821_devlist_mutex);
 
 	if (dev == NULL)
 		pr_info("ERROR ALSA: no cx25821 cards found\n");

index a216b62..523ac5e 100644
@@ -33,9 +33,6 @@ MODULE_DESCRIPTION("Driver for Athena cards");
 MODULE_AUTHOR("Shu Lin - Hiep Huynh");
 MODULE_LICENSE("GPL");
 
-struct list_head cx25821_devlist;
-EXPORT_SYMBOL(cx25821_devlist);
-
 static unsigned int debug;
 module_param(debug, int, 0644);
 MODULE_PARM_DESC(debug, "enable debug messages");

@@ -46,8 +43,10 @@ MODULE_PARM_DESC(card, "card type");
 
 static unsigned int cx25821_devcount;
 
-static DEFINE_MUTEX(devlist);
+DEFINE_MUTEX(cx25821_devlist_mutex);
+EXPORT_SYMBOL(cx25821_devlist_mutex);
 LIST_HEAD(cx25821_devlist);
+EXPORT_SYMBOL(cx25821_devlist);
 
 struct sram_channel cx25821_sram_channels[] = {
 	[SRAM_CH00] = {

@@ -911,9 +910,9 @@ static int cx25821_dev_setup(struct cx25821_dev *dev)
 	dev->nr = ++cx25821_devcount;
 	sprintf(dev->name, "cx25821[%d]", dev->nr);
 
-	mutex_lock(&devlist);
+	mutex_lock(&cx25821_devlist_mutex);
 	list_add_tail(&dev->devlist, &cx25821_devlist);
-	mutex_unlock(&devlist);
+	mutex_unlock(&cx25821_devlist_mutex);
 
 	strcpy(cx25821_boards[UNKNOWN_BOARD].name, "unknown");
 	strcpy(cx25821_boards[CX25821_BOARD].name, "cx25821");

@@ -1465,9 +1464,9 @@ static void __devexit cx25821_finidev(struct pci_dev *pci_dev)
 	if (pci_dev->irq)
 		free_irq(pci_dev->irq, dev);
 
-	mutex_lock(&devlist);
+	mutex_lock(&cx25821_devlist_mutex);
 	list_del(&dev->devlist);
-	mutex_unlock(&devlist);
+	mutex_unlock(&cx25821_devlist_mutex);
 
 	cx25821_dev_unregister(dev);
 	v4l2_device_unregister(v4l2_dev);

@@ -1501,7 +1500,6 @@ static struct pci_driver cx25821_pci_driver = {
 
 static int __init cx25821_init(void)
 {
-	INIT_LIST_HEAD(&cx25821_devlist);
 	pr_info("driver version %d.%d.%d loaded\n",
 		(CX25821_VERSION_CODE >> 16) & 0xff,
 		(CX25821_VERSION_CODE >> 8) & 0xff,

index 0d8d756..ab05392 100644
@@ -27,7 +27,6 @@
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
 #include "cx25821-video.h"
-#include <linux/smp_lock.h>
 
 MODULE_DESCRIPTION("v4l2 driver module for cx25821 based TV cards");
 MODULE_AUTHOR("Hiep Huynh <[email protected]>");

@@ -815,7 +814,7 @@ static int video_open(struct file *file)
        if (NULL == fh)
 	       return -ENOMEM;
 
-       lock_kernel();
+	mutex_lock(&cx25821_devlist_mutex);
 
        list_for_each(list, &cx25821_devlist)
        {

@@ -832,8 +831,8 @@ static int video_open(struct file *file)
        }
 
        if (NULL == dev) {
-	       unlock_kernel();
-	       return -ENODEV;
+		mutex_unlock(&cx25821_devlist_mutex);
+		return -ENODEV;
        }
 
        file->private_data = fh;

@@ -862,7 +861,7 @@ static int video_open(struct file *file)
 			      sizeof(struct cx25821_buffer), fh, NULL);
 
        dprintk(1, "post videobuf_queue_init()\n");
-       unlock_kernel();
+	mutex_unlock(&cx25821_devlist_mutex);
 
        return 0;
 }

index 5511523..6230243 100644
@@ -31,7 +31,6 @@
 #include <linux/delay.h>
 #include <linux/sched.h>
 #include <linux/kdev_t.h>
-#include <linux/smp_lock.h>
 
 #include <media/v4l2-common.h>
 #include <media/v4l2-device.h>

@@ -445,6 +444,8 @@ static inline struct cx25821_dev *get_cx25821(struct v4l2_device *v4l2_dev)
 	v4l2_device_call_all(&dev->v4l2_dev, 0, o, f, ##args)
 
 extern struct list_head cx25821_devlist;
+extern struct mutex cx25821_devlist_mutex;
+
 extern struct cx25821_board cx25821_boards[];
 extern struct cx25821_subid cx25821_subids[];