[media] em28xx: Only deallocate struct em28xx after finishing all extensions

We can't free struct em28xx while one of the extensions is still
using it.

So, add a kref() to control it, freeing it only after the
extensions fini calls.

Reviewed-by: Frank Schäfer <fschaefer.oss@googlemail.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>

drivers/media/usb/em28xx/em28xx-audio.c

@@ -301,6 +301,7 @@ static int snd_em28xx_capture_open(struct snd_pcm_substream *substream)
 			goto err;
 	}
 
+	kref_get(&dev->ref);
 	dev->adev.users++;
 	mutex_unlock(&dev->lock);
 
@@ -341,6 +342,7 @@ static int snd_em28xx_pcm_close(struct snd_pcm_substream *substream)
 		substream->runtime->dma_area = NULL;
 	}
 	mutex_unlock(&dev->lock);
+	kref_put(&dev->ref, em28xx_free_device);
 
 	return 0;
 }
@@ -895,6 +897,8 @@ static int em28xx_audio_init(struct em28xx *dev)
 
 	em28xx_info("Binding audio extension\n");
 
+	kref_get(&dev->ref);
+
 	printk(KERN_INFO "em28xx-audio.c: Copyright (C) 2006 Markus "
 			 "Rechberger\n");
 	printk(KERN_INFO
@@ -967,7 +971,7 @@ static int em28xx_audio_fini(struct em28xx *dev)
 	if (dev == NULL)
 		return 0;
 
-	if (dev->has_alsa_audio != 1) {
+	if (!dev->has_alsa_audio) {
 		/* This device does not support the extension (in this case
 		   the device is expecting the snd-usb-audio module or
 		   doesn't have analog audio support at all) */
@@ -986,6 +990,7 @@ static int em28xx_audio_fini(struct em28xx *dev)
 		dev->adev.sndcard = NULL;
 	}
 
+	kref_put(&dev->ref, em28xx_free_device);
 	return 0;
 }
 

drivers/media/usb/em28xx/em28xx-cards.c

@@ -2939,7 +2939,7 @@ static void flush_request_modules(struct em28xx *dev)
  * unregisters the v4l2,i2c and usb devices
  * called when the device gets disconnected or at module unload
 */
-void em28xx_release_resources(struct em28xx *dev)
+static void em28xx_release_resources(struct em28xx *dev)
 {
 	/*FIXME: I2C IR should be disconnected */
 
@@ -2956,7 +2956,27 @@ void em28xx_release_resources(struct em28xx *dev)
 
 	mutex_unlock(&dev->lock);
 };
-EXPORT_SYMBOL_GPL(em28xx_release_resources);
+
+/**
+ * em28xx_free_device() - Free em28xx device
+ *
+ * @ref: struct kref for em28xx device
+ *
+ * This is called when all extensions and em28xx core unregisters a device
+ */
+void em28xx_free_device(struct kref *ref)
+{
+	struct em28xx *dev = kref_to_dev(ref);
+
+	em28xx_info("Freeing device\n");
+
+	if (!dev->disconnected)
+		em28xx_release_resources(dev);
+
+	kfree(dev->alt_max_pkt_size_isoc);
+	kfree(dev);
+}
+EXPORT_SYMBOL_GPL(em28xx_free_device);
 
 /*
  * em28xx_init_dev()
@@ -3409,6 +3429,8 @@ static int em28xx_usb_probe(struct usb_interface *interface,
 			    dev->dvb_xfer_bulk ? "bulk" : "isoc");
 	}
 
+	kref_init(&dev->ref);
+
 	request_modules(dev);
 
 	/* Should be the last thing to do, to avoid newer udev's to
@@ -3453,11 +3475,7 @@ static void em28xx_usb_disconnect(struct usb_interface *interface)
 	em28xx_close_extension(dev);
 
 	em28xx_release_resources(dev);
-
+	kref_put(&dev->ref, em28xx_free_device);
-	if (!dev->users) {
-		kfree(dev->alt_max_pkt_size_isoc);
-		kfree(dev);
-	}
 }
 
 static int em28xx_usb_suspend(struct usb_interface *interface,

drivers/media/usb/em28xx/em28xx-dvb.c

@@ -1043,7 +1043,6 @@ static int em28xx_dvb_init(struct em28xx *dev)
 	em28xx_info("Binding DVB extension\n");
 
 	dvb = kzalloc(sizeof(struct em28xx_dvb), GFP_KERNEL);
-
 	if (dvb == NULL) {
 		em28xx_info("em28xx_dvb: memory allocation failed\n");
 		return -ENOMEM;
@@ -1521,6 +1520,9 @@ static int em28xx_dvb_init(struct em28xx *dev)
 	dvb->adapter.mfe_shared = mfe_shared;
 
 	em28xx_info("DVB extension successfully initialized\n");
+
+	kref_get(&dev->ref);
+
 ret:
 	em28xx_set_mode(dev, EM28XX_SUSPEND);
 	mutex_unlock(&dev->lock);
@@ -1577,6 +1579,7 @@ static int em28xx_dvb_fini(struct em28xx *dev)
 		em28xx_unregister_dvb(dvb);
 		kfree(dvb);
 		dev->dvb = NULL;
+		kref_put(&dev->ref, em28xx_free_device);
 	}
 
 	return 0;

drivers/media/usb/em28xx/em28xx-input.c

@@ -676,6 +676,8 @@ static int em28xx_ir_init(struct em28xx *dev)
 		return 0;
 	}
 
+	kref_get(&dev->ref);
+
 	if (dev->board.buttons)
 		em28xx_init_buttons(dev);
 
@@ -816,7 +818,7 @@ static int em28xx_ir_fini(struct em28xx *dev)
 
 	/* skip detach on non attached boards */
 	if (!ir)
-		return 0;
+		goto ref_put;
 
 	if (ir->rc)
 		rc_unregister_device(ir->rc);
@@ -824,6 +826,10 @@ static int em28xx_ir_fini(struct em28xx *dev)
 	/* done */
 	kfree(ir);
 	dev->ir = NULL;
+
+ref_put:
+	kref_put(&dev->ref, em28xx_free_device);
+
 	return 0;
 }
 

drivers/media/usb/em28xx/em28xx-video.c

@@ -1837,7 +1837,6 @@ static int em28xx_v4l2_open(struct file *filp)
 			video_device_node_name(vdev), v4l2_type_names[fh_type],
 			dev->users);
 
-
 	if (mutex_lock_interruptible(&dev->lock))
 		return -ERESTARTSYS;
 	fh = kzalloc(sizeof(struct em28xx_fh), GFP_KERNEL);
@@ -1869,6 +1868,7 @@ static int em28xx_v4l2_open(struct file *filp)
 		v4l2_device_call_all(&dev->v4l2_dev, 0, tuner, s_radio);
 	}
 
+	kref_get(&dev->ref);
 	dev->users++;
 
 	mutex_unlock(&dev->lock);
@@ -1926,9 +1926,8 @@ static int em28xx_v4l2_fini(struct em28xx *dev)
 		dev->clk = NULL;
 	}
 
-	if (dev->users)
-		em28xx_warn("Device is open ! Memory deallocation is deferred on last close.\n");
 	mutex_unlock(&dev->lock);
+	kref_put(&dev->ref, em28xx_free_device);
 
 	return 0;
 }
@@ -1976,11 +1975,9 @@ static int em28xx_v4l2_close(struct file *filp)
 	mutex_lock(&dev->lock);
 
 	if (dev->users == 1) {
-		/* free the remaining resources if device is disconnected */
+		/* No sense to try to write to the device */
-		if (dev->disconnected) {
+		if (dev->disconnected)
-			kfree(dev->alt_max_pkt_size_isoc);
 			goto exit;
-		}
 
 		/* Save some power by putting tuner to sleep */
 		v4l2_device_call_all(&dev->v4l2_dev, 0, core, s_power, 0);
@@ -2001,6 +1998,8 @@ static int em28xx_v4l2_close(struct file *filp)
 exit:
 	dev->users--;
 	mutex_unlock(&dev->lock);
+	kref_put(&dev->ref, em28xx_free_device);
+
 	return 0;
 }
 
@@ -2515,6 +2514,8 @@ static int em28xx_v4l2_init(struct em28xx *dev)
 
 	em28xx_info("V4L2 extension successfully initialized\n");
 
+	kref_get(&dev->ref);
+
 	mutex_unlock(&dev->lock);
 	return 0;
 

drivers/media/usb/em28xx/em28xx.h

@@ -32,6 +32,7 @@
 #include <linux/workqueue.h>
 #include <linux/i2c.h>
 #include <linux/mutex.h>
+#include <linux/kref.h>
 #include <linux/videodev2.h>
 
 #include <media/videobuf2-vmalloc.h>
@@ -536,9 +537,10 @@ struct em28xx_i2c_bus {
 	enum em28xx_i2c_algo_type algo_type;
 };
 
-
 /* main device struct */
 struct em28xx {
+	struct kref ref;
+
 	/* generic device properties */
 	char name[30];		/* name (including minor) of the device */
 	int model;		/* index in the device_data struct */
@@ -710,6 +712,8 @@ struct em28xx {
 	struct em28xx_dvb *dvb;
 };
 
+#define kref_to_dev(d) container_of(d, struct em28xx, ref)
+
 struct em28xx_ops {
 	struct list_head next;
 	char *name;
@@ -771,7 +775,7 @@ extern struct em28xx_board em28xx_boards[];
 extern struct usb_device_id em28xx_id_table[];
 int em28xx_tuner_callback(void *ptr, int component, int command, int arg);
 void em28xx_setup_xc3028(struct em28xx *dev, struct xc2028_ctrl *ctl);
-void em28xx_release_resources(struct em28xx *dev);
+void em28xx_free_device(struct kref *ref);
 
 /* Provided by em28xx-camera.c */
 int em28xx_detect_sensor(struct em28xx *dev);