V4L/DVB (9086): gspca: Use a kref to avoid potentialy blocking forever in disconnect.
Signed-off-by: Frank Zago <frank@zago.net>
Signed-off-by: Jean-Francois Moine <moinejf@free.fr>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/video/gspca/gspca.c b/drivers/media/video/gspca/gspca.c
index 3f0fd44..342a0f3 100644
--- a/drivers/media/video/gspca/gspca.c
+++ b/drivers/media/video/gspca/gspca.c
@@ -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 @@
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 @@
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 @@
}
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 @@
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 @@
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 @@
{
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 @@
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);