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Commit 6b060ffe authored by Frank Zago's avatar Frank Zago Committed by Mauro Carvalho Chehab
Browse files

V4L/DVB (9086): gspca: Use a kref to avoid potentialy blocking forever in disconnect. 



Signed-off-by: default avatarFrank Zago <frank@zago.net>
Signed-off-by: default avatarJean-Francois Moine <moinejf@free.fr>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@redhat.com>
parent 6c49da7f

drivers/media/video/gspca/gspca.c

+27 −12
Original line number Diff line number Diff line
@@ -29,6 +29,7 @@ 
#include <linux/string.h>

#include <linux/pagemap.h>

#include <linux/io.h>

#include <linux/kref.h>

#include <asm/page.h>

#include <linux/uaccess.h>

#include <linux/jiffies.h>
@@ -834,6 +835,16 @@ static int vidioc_s_fmt_vid_cap(struct file *file, void *priv, 
	return ret;

}



static void gspca_delete(struct kref *kref)

{

	struct gspca_dev *gspca_dev = container_of(kref, struct gspca_dev, kref);



	PDEBUG(D_STREAM, "device deleted");



	kfree(gspca_dev->usb_buf);

	kfree(gspca_dev);

}



static int dev_open(struct inode *inode, struct file *file)

{

	struct gspca_dev *gspca_dev;
@@ -853,6 +864,10 @@ static int dev_open(struct inode *inode, struct file *file) 
		goto out;

	}

	gspca_dev->users++;



	/* one more user */

	kref_get(&gspca_dev->kref);



	file->private_data = gspca_dev;

#ifdef GSPCA_DEBUG

	/* activate the v4l2 debug */
@@ -895,7 +910,11 @@ static int dev_close(struct inode *inode, struct file *file) 
	}

	file->private_data = NULL;

	mutex_unlock(&gspca_dev->queue_lock);



	PDEBUG(D_STREAM, "close done");



	kref_put(&gspca_dev->kref, gspca_delete);



	return 0;

}
@@ -1809,6 +1828,7 @@ int gspca_dev_probe(struct usb_interface *intf, 
		err("couldn't kzalloc gspca struct");

		return -EIO;

	}

	kref_init(&gspca_dev->kref);

	gspca_dev->usb_buf = kmalloc(USB_BUF_SZ, GFP_KERNEL);

	if (!gspca_dev->usb_buf) {

		err("out of memory");
@@ -1858,8 +1878,7 @@ int gspca_dev_probe(struct usb_interface *intf, 
	PDEBUG(D_PROBE, "probe ok");

	return 0;

out:

	kfree(gspca_dev->usb_buf);

	kfree(gspca_dev);

	kref_put(&gspca_dev->kref, gspca_delete);

	return ret;

}

EXPORT_SYMBOL(gspca_dev_probe);
@@ -1874,8 +1893,8 @@ void gspca_disconnect(struct usb_interface *intf) 
{

	struct gspca_dev *gspca_dev = usb_get_intfdata(intf);



	if (!gspca_dev)

		return;

	usb_set_intfdata(intf, NULL);



	gspca_dev->present = 0;

	mutex_lock(&gspca_dev->queue_lock);

	mutex_lock(&gspca_dev->usb_lock);
@@ -1883,16 +1902,12 @@ void gspca_disconnect(struct usb_interface *intf) 
	destroy_urbs(gspca_dev);

	mutex_unlock(&gspca_dev->usb_lock);

	mutex_unlock(&gspca_dev->queue_lock);

	while (gspca_dev->users != 0) {		/* wait until fully closed */

		atomic_inc(&gspca_dev->nevent);

		wake_up_interruptible(&gspca_dev->wq);	/* wake processes */

		schedule();

	}



/* We don't want people trying to open up the device */

	video_unregister_device(&gspca_dev->vdev);

/* Free the memory */

	kfree(gspca_dev->usb_buf);

	kfree(gspca_dev);



	kref_put(&gspca_dev->kref, gspca_delete);



	PDEBUG(D_PROBE, "disconnect complete");

}

EXPORT_SYMBOL(gspca_disconnect);

drivers/media/video/gspca/gspca.h

+1 −0
Original line number Diff line number Diff line
@@ -121,6 +121,7 @@ struct gspca_dev { 
	struct video_device vdev;	/* !! must be the first item */

	struct file_operations fops;

	struct usb_device *dev;

	struct kref kref;

	struct file *capt_file;		/* file doing video capture */



	struct cam cam;				/* device information */