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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: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Ian Abbott 2014-11-04 18:09:01 +00:00 committed by Greg Kroah-Hartman
parent 20f083c075
commit c299a6789c
3 changed files with 94 additions and 0 deletions
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2
drivers/staging/comedi/comedi.h
View File

@ -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 */

2
drivers/staging/comedi/comedi_compat32.c
View File

@ -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;

90
drivers/staging/comedi/comedi_fops.c
View File

@ -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;