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Commit c299a678 authored by Ian Abbott's avatar Ian Abbott Committed by Greg Kroah-Hartman
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staging: comedi: add ioctls to set per-file read and write subdevice 



Now that Comedi has the structures in place to support setting the
current "read" and/or "write" subdevice on a per-file object basis, add
new ioctls to set them.  The newly chosen "read" ("write") subdevice
needs to support "read" ("write") commands, and the file cannot be busy
handling a "read" ("write") command on the previous subdevice (if any).

Signed-off-by: default avatarIan Abbott <abbotti@mev.co.uk>
Reviewed-by: default avatarH Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 20f083c0

drivers/staging/comedi/comedi.h

+2 −0
Original line number Diff line number Diff line
@@ -367,6 +367,8 @@ enum comedi_support_level { 
#define COMEDI_BUFCONFIG _IOR(CIO, 13, struct comedi_bufconfig)

#define COMEDI_BUFINFO _IOWR(CIO, 14, struct comedi_bufinfo)

#define COMEDI_POLL _IO(CIO, 15)

#define COMEDI_SETRSUBD _IO(CIO, 16)

#define COMEDI_SETWSUBD _IO(CIO, 17)



/* structures */

drivers/staging/comedi/comedi_compat32.c

+2 −0
Original line number Diff line number Diff line
@@ -416,6 +416,8 @@ static inline int raw_ioctl(struct file *file, unsigned int cmd, 
	case COMEDI_UNLOCK:

	case COMEDI_CANCEL:

	case COMEDI_POLL:

	case COMEDI_SETRSUBD:

	case COMEDI_SETWSUBD:

		/* No translation needed. */

		rc = translated_ioctl(file, cmd, arg);

		break;

drivers/staging/comedi/comedi_fops.c

+90 −0
Original line number Diff line number Diff line
@@ -1847,6 +1847,90 @@ static int do_poll_ioctl(struct comedi_device *dev, unsigned long arg, 
	return -EINVAL;

}



/*

 * COMEDI_SETRSUBD ioctl

 * sets the current "read" subdevice on a per-file basis

 *

 * arg:

 *	subdevice number

 *

 * reads:

 *	nothing

 *

 * writes:

 *	nothing

 */

static int do_setrsubd_ioctl(struct comedi_device *dev, unsigned long arg,

			     struct file *file)

{

	struct comedi_file *cfp = file->private_data;

	struct comedi_subdevice *s_old, *s_new;



	if (arg >= dev->n_subdevices)

		return -EINVAL;



	s_new = &dev->subdevices[arg];

	s_old = comedi_file_read_subdevice(file);

	if (s_old == s_new)

		return 0;	/* no change */



	if (!(s_new->subdev_flags & SDF_CMD_READ))

		return -EINVAL;



	/*

	 * Check the file isn't still busy handling a "read" command on the

	 * old subdevice (if any).

	 */

	if (s_old && s_old->busy == file && s_old->async &&

	    !(s_old->async->cmd.flags & CMDF_WRITE))

		return -EBUSY;



	ACCESS_ONCE(cfp->read_subdev) = s_new;

	return 0;

}



/*

 * COMEDI_SETWSUBD ioctl

 * sets the current "write" subdevice on a per-file basis

 *

 * arg:

 *	subdevice number

 *

 * reads:

 *	nothing

 *

 * writes:

 *	nothing

 */

static int do_setwsubd_ioctl(struct comedi_device *dev, unsigned long arg,

			     struct file *file)

{

	struct comedi_file *cfp = file->private_data;

	struct comedi_subdevice *s_old, *s_new;



	if (arg >= dev->n_subdevices)

		return -EINVAL;



	s_new = &dev->subdevices[arg];

	s_old = comedi_file_write_subdevice(file);

	if (s_old == s_new)

		return 0;	/* no change */



	if (!(s_new->subdev_flags & SDF_CMD_WRITE))

		return -EINVAL;



	/*

	 * Check the file isn't still busy handling a "write" command on the

	 * old subdevice (if any).

	 */

	if (s_old && s_old->busy == file && s_old->async &&

	    (s_old->async->cmd.flags & CMDF_WRITE))

		return -EBUSY;



	ACCESS_ONCE(cfp->write_subdev) = s_new;

	return 0;

}



static long comedi_unlocked_ioctl(struct file *file, unsigned int cmd,

				  unsigned long arg)

{
@@ -1941,6 +2025,12 @@ static long comedi_unlocked_ioctl(struct file *file, unsigned int cmd, 
	case COMEDI_POLL:

		rc = do_poll_ioctl(dev, arg, file);

		break;

	case COMEDI_SETRSUBD:

		rc = do_setrsubd_ioctl(dev, arg, file);

		break;

	case COMEDI_SETWSUBD:

		rc = do_setwsubd_ioctl(dev, arg, file);

		break;

	default:

		rc = -ENOTTY;

		break;