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Commit bd5b4173 authored by Ian Abbott's avatar Ian Abbott Committed by Greg Kroah-Hartman
Browse files

staging: comedi: simplify comedi_subdevice_minor_table[] 



`comedi_alloc_subdevice_minor()` allocates and initializes a `struct
comedi_file_info` and assigns a subdevice minor device number (if there
are any available), storing a pointer to the allocated `struct
comedi_file_info` in `comedi_subdevice_minor_table[i]` where `i` is the
array index corresponding to the subdevice minor device number (indexed
by subdevice minor device number minus `COMEDI_NUM_BOARD_MINORS`).

The information stored in the `struct comedi_file_info` can be derived
from the subdevice structure (`struct comedi_subdevice`) itself, so the
`struct comedi_file_info` is superfluous.

Change `comedi_subdevice_minor_table[]` to hold pointers to the actual
`struct comedi_subdevice`'s.  `comedi_alloc_subdevice_minor()` no longer
needs to allocate a `struct comedi_file_info` and
`comedi_free_subdevice_info()` no longer has a `struct comedi_file_info`
to free.

Replace `comedi_file_info_from_minor()` with
`comedi_subdevice_from_minor()`, returning a (possibly NULL) pointer to
a `struct comedi_subdevice` from the table.  This has knock-on effects
for `comedi_dev_from_subdevice_minor()`, `comedi_read_subdevice()` and
`comedi_write_subdevice()`.  In particular, `comedi_read_subdevice()`
and `comedi_write_subdevice()` now need to check the subdevice flags to
see if the determine whether to override the comedi device's default
read/write subdevice.

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 dac59de2

drivers/staging/comedi/comedi_fops.c

+22 −34
Original line number Diff line number Diff line
@@ -93,7 +93,7 @@ static struct comedi_file_info 


static DEFINE_MUTEX(comedi_subdevice_minor_table_lock);

/* Note: indexed by minor - COMEDI_NUM_BOARD_MINORS. */

static struct comedi_file_info

static struct comedi_subdevice

*comedi_subdevice_minor_table[COMEDI_NUM_SUBDEVICE_MINORS];



static struct class *comedi_class;
@@ -153,17 +153,17 @@ static void comedi_free_board_file_info(struct comedi_file_info *info) 
	}

}



static struct comedi_file_info

*comedi_file_info_from_subdevice_minor(unsigned minor)

static struct comedi_subdevice

*comedi_subdevice_from_minor(unsigned minor)

{

	struct comedi_file_info *info;

	struct comedi_subdevice *s;

	unsigned int i = minor - COMEDI_NUM_BOARD_MINORS;



	BUG_ON(i >= COMEDI_NUM_SUBDEVICE_MINORS);

	mutex_lock(&comedi_subdevice_minor_table_lock);

	info = comedi_subdevice_minor_table[i];

	s = comedi_subdevice_minor_table[i];

	mutex_unlock(&comedi_subdevice_minor_table_lock);

	return info;

	return s;

}



static struct comedi_device *
@@ -185,10 +185,10 @@ static struct comedi_device *comedi_dev_from_board_minor(unsigned minor) 


static struct comedi_device *comedi_dev_from_subdevice_minor(unsigned minor)

{

	struct comedi_file_info *info;

	struct comedi_subdevice *s;



	info = comedi_file_info_from_subdevice_minor(minor);

	return comedi_dev_from_file_info(info);

	s = comedi_subdevice_from_minor(minor);

	return s ? s->device : NULL;

}



struct comedi_device *comedi_dev_from_minor(unsigned minor)
@@ -203,14 +203,14 @@ EXPORT_SYMBOL_GPL(comedi_dev_from_minor); 
static struct comedi_subdevice *

comedi_read_subdevice(const struct comedi_device *dev, unsigned int minor)

{

	struct comedi_file_info *info;

	struct comedi_subdevice *s;



	if (minor >= COMEDI_NUM_BOARD_MINORS) {

		info = comedi_file_info_from_subdevice_minor(minor);

		if (!info || info->device != dev)

		s = comedi_subdevice_from_minor(minor);

		if (!s || s->device != dev)

			return NULL;

		if (info->read_subdevice)

			return info->read_subdevice;

		if (s->subdev_flags & SDF_CMD_READ)

			return s;

	}

	return dev->read_subdev;

}
@@ -218,14 +218,14 @@ comedi_read_subdevice(const struct comedi_device *dev, unsigned int minor) 
static struct comedi_subdevice *

comedi_write_subdevice(const struct comedi_device *dev, unsigned int minor)

{

	struct comedi_file_info *info;

	struct comedi_subdevice *s;



	if (minor >= COMEDI_NUM_BOARD_MINORS) {

		info = comedi_file_info_from_subdevice_minor(minor);

		if (!info || info->device != dev)

		s = comedi_subdevice_from_minor(minor);

		if (!s || s->device != dev)

			return NULL;

		if (info->write_subdevice)

			return info->write_subdevice;

		if (s->subdev_flags & SDF_CMD_WRITE)

			return s;

	}

	return dev->write_subdev;

}
@@ -2468,28 +2468,18 @@ void comedi_release_hardware_device(struct device *hardware_device) 
int comedi_alloc_subdevice_minor(struct comedi_subdevice *s)

{

	struct comedi_device *dev = s->device;

	struct comedi_file_info *info;

	struct device *csdev;

	unsigned i;



	info = kzalloc(sizeof(*info), GFP_KERNEL);

	if (!info)

		return -ENOMEM;

	info->device = dev;

	if (s->subdev_flags & SDF_CMD_READ)

		info->read_subdevice = s;

	if (s->subdev_flags & SDF_CMD_WRITE)

		info->write_subdevice = s;

	mutex_lock(&comedi_subdevice_minor_table_lock);

	for (i = 0; i < COMEDI_NUM_SUBDEVICE_MINORS; ++i) {

		if (comedi_subdevice_minor_table[i] == NULL) {

			comedi_subdevice_minor_table[i] = info;

			comedi_subdevice_minor_table[i] = s;

			break;

		}

	}

	mutex_unlock(&comedi_subdevice_minor_table_lock);

	if (i == COMEDI_NUM_SUBDEVICE_MINORS) {

		kfree(info);

		pr_err("comedi: error: ran out of minor numbers for subdevice files.\n");

		return -EBUSY;

	}
@@ -2506,7 +2496,6 @@ int comedi_alloc_subdevice_minor(struct comedi_subdevice *s) 


void comedi_free_subdevice_minor(struct comedi_subdevice *s)

{

	struct comedi_file_info *info;

	unsigned int i;



	if (s == NULL)
@@ -2519,14 +2508,13 @@ void comedi_free_subdevice_minor(struct comedi_subdevice *s) 


	i = s->minor - COMEDI_NUM_BOARD_MINORS;

	mutex_lock(&comedi_subdevice_minor_table_lock);

	info = comedi_subdevice_minor_table[i];

	if (s == comedi_subdevice_minor_table[i])

		comedi_subdevice_minor_table[i] = NULL;

	mutex_unlock(&comedi_subdevice_minor_table_lock);

	if (s->class_dev) {

		device_destroy(comedi_class, MKDEV(COMEDI_MAJOR, s->minor));

		s->class_dev = NULL;

	}

	kfree(info);

}



static void comedi_cleanup_board_minors(void)