Commit 5dd3f307 authored by Andreas Oberritter's avatar Andreas Oberritter Committed by Mauro Carvalho Chehab
Browse files

V4L/DVB (9361): Dynamic DVB minor allocation 



Implement dynamic minor allocation for DVB, to allow more than four
devices of the same type per adapter, based on drivers/usb/core/file.c.

Add a new config option, DVB_DYNAMIC_MINORS, to make use of this
feature, which defaults to no for backwards compatibility.

Signed-off-by: default avatarAndreas Oberritter <obi@linuxtv.org>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@redhat.com>
parent 568e9bb8

drivers/media/dvb/Kconfig

+13 −0
Original line number Diff line number Diff line
@@ -2,6 +2,19 @@ 
# DVB device configuration

#



config DVB_DYNAMIC_MINORS

	bool "Dynamic DVB minor allocation"

	depends on DVB_CORE

	default n

	help

	  If you say Y here, the DVB subsystem will use dynamic minor

	  allocation for any device that uses the DVB major number.

	  This means that you can have more than 4 of a single type

	  of device (like demuxes and frontends) per adapter, but udev

	  will be required to manage the device nodes.



	  If you are unsure about this, say N here.



menuconfig DVB_CAPTURE_DRIVERS

	bool "DVB/ATSC adapters"

	depends on DVB_CORE

drivers/media/dvb/dvb-core/dvbdev.c

+38 −19
Original line number Diff line number Diff line
@@ -50,33 +50,27 @@ static const char * const dnames[] = { 
	"net", "osd"

};



#ifdef CONFIG_DVB_DYNAMIC_MINORS

#define MAX_DVB_MINORS		256

#define DVB_MAX_IDS		MAX_DVB_MINORS

#else

#define DVB_MAX_IDS		4

#define nums2minor(num,type,id)	((num << 6) | (id << 4) | type)

#define MAX_DVB_MINORS		(DVB_MAX_ADAPTERS*64)

#endif



static struct class *dvb_class;



static struct dvb_device* dvbdev_find_device (int minor)

{

	struct dvb_adapter *adap;



	list_for_each_entry(adap, &dvb_adapter_list, list_head) {

		struct dvb_device *dev;

		list_for_each_entry(dev, &adap->device_list, list_head)

			if (nums2minor(adap->num, dev->type, dev->id) == minor)

				return dev;

	}



	return NULL;

}



static struct dvb_device *dvb_minors[MAX_DVB_MINORS];

static DECLARE_RWSEM(minor_rwsem);



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

{

	struct dvb_device *dvbdev;



	lock_kernel();

	dvbdev = dvbdev_find_device (iminor(inode));

	down_read(&minor_rwsem);

	dvbdev = dvb_minors[iminor(inode)];



	if (dvbdev && dvbdev->fops) {

		int err = 0;
@@ -92,9 +86,11 @@ static int dvb_device_open(struct inode *inode, struct file *file) 
			file->f_op = fops_get(old_fops);

		}

		fops_put(old_fops);

		up_read(&minor_rwsem);

		unlock_kernel();

		return err;

	}

	up_read(&minor_rwsem);

	unlock_kernel();

	return -ENODEV;

}
@@ -192,6 +188,7 @@ int dvb_register_device(struct dvb_adapter *adap, struct dvb_device **pdvbdev, 
	struct dvb_device *dvbdev;

	struct file_operations *dvbdevfops;

	struct device *clsdev;

	int minor;

	int id;



	mutex_lock(&dvbdev_register_lock);
@@ -231,6 +228,26 @@ int dvb_register_device(struct dvb_adapter *adap, struct dvb_device **pdvbdev, 


	list_add_tail (&dvbdev->list_head, &adap->device_list);



	down_write(&minor_rwsem);

#ifdef CONFIG_DVB_DYNAMIC_MINORS

	for (minor = 0; minor < MAX_DVB_MINORS; minor++)

		if (dvb_minors[minor] == NULL)

			break;



	if (minor == MAX_DVB_MINORS) {

		kfree(dvbdevfops);

		kfree(dvbdev);

		mutex_unlock(&dvbdev_register_lock);

		return -EINVAL;

	}

#else

	minor = nums2minor(adap->num, type, id);

#endif



	dvbdev->minor = minor;

	dvb_minors[minor] = dvbdev;

	up_write(&minor_rwsem);



	mutex_unlock(&dvbdev_register_lock);



	clsdev = device_create(dvb_class, adap->device,
@@ -243,8 +260,7 @@ int dvb_register_device(struct dvb_adapter *adap, struct dvb_device **pdvbdev, 
	}



	dprintk(KERN_DEBUG "DVB: register adapter%d/%s%d @ minor: %i (0x%02x)\n",

		adap->num, dnames[type], id, nums2minor(adap->num, type, id),

		nums2minor(adap->num, type, id));

		adap->num, dnames[type], id, minor, minor);



	return 0;

}
@@ -256,8 +272,11 @@ void dvb_unregister_device(struct dvb_device *dvbdev) 
	if (!dvbdev)

		return;



	device_destroy(dvb_class, MKDEV(DVB_MAJOR, nums2minor(dvbdev->adapter->num,

		       dvbdev->type, dvbdev->id)));

	down_write(&minor_rwsem);

	dvb_minors[dvbdev->minor] = NULL;

	up_write(&minor_rwsem);



	device_destroy(dvb_class, MKDEV(DVB_MAJOR, dvbdev->minor));



	list_del (&dvbdev->list_head);

	kfree (dvbdev->fops);

drivers/media/dvb/dvb-core/dvbdev.h

+1 −0
Original line number Diff line number Diff line
@@ -74,6 +74,7 @@ struct dvb_device { 
	struct file_operations *fops;

	struct dvb_adapter *adapter;

	int type;

	int minor;

	u32 id;



	/* in theory, 'users' can vanish now,