Commit c43435d7 authored by Ian Abbott's avatar Ian Abbott Committed by Greg Kroah-Hartman
Browse files

staging: comedi: don't hijack hardware device private data 



comedi_auto_config() associates a Comedi minor device number with an
auto-configured hardware device and comedi_auto_unconfig() disassociates
it.  Currently, these use the hardware device's private data pointer to
point to some allocated storage holding the minor device number.  This
is a bit of a waste of the hardware device's private data pointer,
preventing it from being used for something more useful by the low-level
comedi device drivers.  For example, it would make more sense if
comedi_usb_auto_config() was passed a pointer to the struct
usb_interface instead of the struct usb_device, but this cannot be done
currently because the low-level comedi drivers already use the private
data pointer in the struct usb_interface for something more useful.

This patch stops the comedi core hijacking the hardware device's private
data pointer.  Instead, comedi_auto_config() stores a pointer to the
hardware device's struct device in the struct comedi_device_file_info
associated with the minor device number, and comedi_auto_unconfig()
calls new function comedi_find_board_minor() to recover the minor device
number associated with the hardware device.

Signed-off-by: default avatarIan Abbott <abbotti@mev.co.uk>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 7cbd8f3d

drivers/staging/comedi/comedi_fops.c

+18 −0
Original line number Diff line number Diff line
@@ -2205,6 +2205,7 @@ int comedi_alloc_board_minor(struct device *hardware_device) 
		kfree(info);

		return -ENOMEM;

	}

	info->hardware_device = hardware_device;

	comedi_device_init(info->device);

	spin_lock(&comedi_file_info_table_lock);

	for (i = 0; i < COMEDI_NUM_BOARD_MINORS; ++i) {
@@ -2292,6 +2293,23 @@ void comedi_free_board_minor(unsigned minor) 
	}

}



int comedi_find_board_minor(struct device *hardware_device)

{

	int minor;

	struct comedi_device_file_info *info;



	for (minor = 0; minor < COMEDI_NUM_BOARD_MINORS; minor++) {

		spin_lock(&comedi_file_info_table_lock);

		info = comedi_file_info_table[minor];

		if (info && info->hardware_device == hardware_device) {

			spin_unlock(&comedi_file_info_table_lock);

			return minor;

		}

		spin_unlock(&comedi_file_info_table_lock);

	}

	return -ENODEV;

}



int comedi_alloc_subdevice_minor(struct comedi_device *dev,

				 struct comedi_subdevice *s)

{

drivers/staging/comedi/comedidev.h

+1 −0
Original line number Diff line number Diff line
@@ -234,6 +234,7 @@ struct comedi_device_file_info { 
	struct comedi_device *device;

	struct comedi_subdevice *read_subdevice;

	struct comedi_subdevice *write_subdevice;

	struct device *hardware_device;

};



#ifdef CONFIG_COMEDI_DEBUG

drivers/staging/comedi/drivers.c

+10 −24
Original line number Diff line number Diff line
@@ -822,25 +822,14 @@ static int comedi_auto_config(struct device *hardware_device, 
	int minor;

	struct comedi_device_file_info *dev_file_info;

	int retval;

	unsigned *private_data = NULL;



	if (!comedi_autoconfig) {

		dev_set_drvdata(hardware_device, NULL);

	if (!comedi_autoconfig)

		return 0;

	}



	minor = comedi_alloc_board_minor(hardware_device);

	if (minor < 0)

		return minor;



	private_data = kmalloc(sizeof(unsigned), GFP_KERNEL);

	if (private_data == NULL) {

		retval = -ENOMEM;

		goto cleanup;

	}

	*private_data = minor;

	dev_set_drvdata(hardware_device, private_data);



	dev_file_info = comedi_get_device_file_info(minor);



	memset(&it, 0, sizeof(it));
@@ -853,25 +842,22 @@ static int comedi_auto_config(struct device *hardware_device, 
	retval = comedi_device_attach(dev_file_info->device, &it);

	mutex_unlock(&dev_file_info->device->mutex);



cleanup:

	if (retval < 0) {

		kfree(private_data);

	if (retval < 0)

		comedi_free_board_minor(minor);

	}

	return retval;

}



static void comedi_auto_unconfig(struct device *hardware_device)

{

	unsigned *minor = (unsigned *)dev_get_drvdata(hardware_device);

	if (minor == NULL)

		return;



	BUG_ON(*minor >= COMEDI_NUM_BOARD_MINORS);

	int minor;



	comedi_free_board_minor(*minor);

	dev_set_drvdata(hardware_device, NULL);

	kfree(minor);

	if (hardware_device == NULL)

		return;

	minor = comedi_find_board_minor(hardware_device);

	if (minor < 0)

		return;

	BUG_ON(minor >= COMEDI_NUM_BOARD_MINORS);

	comedi_free_board_minor(minor);

}



int comedi_pci_auto_config(struct pci_dev *pcidev, struct comedi_driver *driver)

drivers/staging/comedi/internal.h

+1 −0
Original line number Diff line number Diff line
@@ -7,6 +7,7 @@ int insn_inval(struct comedi_device *dev, struct comedi_subdevice *s, 
	       struct comedi_insn *insn, unsigned int *data);

int comedi_alloc_board_minor(struct device *hardware_device);

void comedi_free_board_minor(unsigned minor);

int comedi_find_board_minor(struct device *hardware_device);

void comedi_reset_async_buf(struct comedi_async *async);

int comedi_buf_alloc(struct comedi_device *dev, struct comedi_subdevice *s,

		     unsigned long new_size);

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