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Commit da619f55 authored by Ian Abbott's avatar Ian Abbott Committed by Greg Kroah-Hartman
Browse files

staging: comedi: change comedi_file_info_table_lock to mutex 



The spin-lock `comedi_file_info_table_lock` is used to protect against
simultaneous modification and access of `comedi_file_info_table[]`.
Change it from a spin-lock to a mutex as it is only used in contexts
where sleeping is allowed.

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 db2e3487

drivers/staging/comedi/comedi_fops.c

+12 −12
Original line number Diff line number Diff line
@@ -84,7 +84,7 @@ struct comedi_file_info { 
	struct device *hardware_device;

};



static DEFINE_SPINLOCK(comedi_file_info_table_lock);

static DEFINE_MUTEX(comedi_file_info_table_lock);

static struct comedi_file_info *comedi_file_info_table[COMEDI_NUM_MINORS];



static struct class *comedi_class;
@@ -121,10 +121,10 @@ static struct comedi_file_info *comedi_clear_minor(unsigned minor) 
{

	struct comedi_file_info *info;



	spin_lock(&comedi_file_info_table_lock);

	mutex_lock(&comedi_file_info_table_lock);

	info = comedi_file_info_table[minor];

	comedi_file_info_table[minor] = NULL;

	spin_unlock(&comedi_file_info_table_lock);

	mutex_unlock(&comedi_file_info_table_lock);

	return info;

}
@@ -149,9 +149,9 @@ static struct comedi_file_info *comedi_file_info_from_minor(unsigned minor) 
	struct comedi_file_info *info;



	BUG_ON(minor >= COMEDI_NUM_MINORS);

	spin_lock(&comedi_file_info_table_lock);

	mutex_lock(&comedi_file_info_table_lock);

	info = comedi_file_info_table[minor];

	spin_unlock(&comedi_file_info_table_lock);

	mutex_unlock(&comedi_file_info_table_lock);

	return info;

}
@@ -2328,7 +2328,7 @@ struct comedi_device *comedi_alloc_board_minor(struct device *hardware_device) 
	comedi_device_init(dev);

	comedi_set_hw_dev(dev, hardware_device);

	mutex_lock(&dev->mutex);

	spin_lock(&comedi_file_info_table_lock);

	mutex_lock(&comedi_file_info_table_lock);

	for (i = hardware_device ? comedi_num_legacy_minors : 0;

	     i < COMEDI_NUM_BOARD_MINORS; ++i) {

		if (comedi_file_info_table[i] == NULL) {
@@ -2336,7 +2336,7 @@ struct comedi_device *comedi_alloc_board_minor(struct device *hardware_device) 
			break;

		}

	}

	spin_unlock(&comedi_file_info_table_lock);

	mutex_unlock(&comedi_file_info_table_lock);

	if (i == COMEDI_NUM_BOARD_MINORS) {

		mutex_unlock(&dev->mutex);

		comedi_device_cleanup(dev);
@@ -2369,15 +2369,15 @@ void comedi_release_hardware_device(struct device *hardware_device) 


	for (minor = comedi_num_legacy_minors; minor < COMEDI_NUM_BOARD_MINORS;

	     minor++) {

		spin_lock(&comedi_file_info_table_lock);

		mutex_lock(&comedi_file_info_table_lock);

		info = comedi_file_info_table[minor];

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

			comedi_file_info_table[minor] = NULL;

			spin_unlock(&comedi_file_info_table_lock);

			mutex_unlock(&comedi_file_info_table_lock);

			comedi_free_board_file_info(info);

			break;

		}

		spin_unlock(&comedi_file_info_table_lock);

		mutex_unlock(&comedi_file_info_table_lock);

	}

}
@@ -2396,14 +2396,14 @@ int comedi_alloc_subdevice_minor(struct comedi_subdevice *s) 
		info->read_subdevice = s;

	if (s->subdev_flags & SDF_CMD_WRITE)

		info->write_subdevice = s;

	spin_lock(&comedi_file_info_table_lock);

	mutex_lock(&comedi_file_info_table_lock);

	for (i = COMEDI_FIRST_SUBDEVICE_MINOR; i < COMEDI_NUM_MINORS; ++i) {

		if (comedi_file_info_table[i] == NULL) {

			comedi_file_info_table[i] = info;

			break;

		}

	}

	spin_unlock(&comedi_file_info_table_lock);

	mutex_unlock(&comedi_file_info_table_lock);

	if (i == COMEDI_NUM_MINORS) {

		kfree(info);

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