Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit bb01443e authored by Lars-Peter Clausen's avatar Lars-Peter Clausen Committed by Greg Kroah-Hartman
Browse files

staging:iio: Make sure a device is only opened once at a time 



Our buffer implementation does not support multiple concurrent readers. So we
have to ensure that a device is only opened once at a time. So do the same thing
we do for the event fd and introduce a per device busy flag. The flag gets set
when opening the device and gets cleared when closing the device. If a open is
attempted while the busy flag is set we return -EBUSY.

Acked-by: default avatarJonathan Cameron <jic23@kernel.org>
Signed-off-by: default avatarLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent e38c79e0

drivers/staging/iio/iio.h

+3 −0
Original line number Diff line number Diff line
@@ -313,6 +313,7 @@ struct iio_buffer_setup_ops { 
 * @chrdev:		[INTERN] associated character device

 * @groups:		[INTERN] attribute groups

 * @groupcounter:	[INTERN] index of next attribute group

 * @flags:		[INTERN] file ops related flags including busy flag.

 **/

struct iio_dev {

	int				id;
@@ -344,6 +345,8 @@ struct iio_dev { 
#define IIO_MAX_GROUPS 6

	const struct attribute_group	*groups[IIO_MAX_GROUPS + 1];

	int				groupcounter;



	unsigned long			flags;

};



/**

drivers/staging/iio/industrialio-core.c

+14 −3
Original line number Diff line number Diff line
@@ -1083,9 +1083,18 @@ static int iio_chrdev_open(struct inode *inode, struct file *filp) 
{

	struct iio_dev *indio_dev = container_of(inode->i_cdev,

						struct iio_dev, chrdev);

	unsigned int ret;



	if (test_and_set_bit(IIO_BUSY_BIT_POS, &indio_dev->flags))

		return -EBUSY;



	filp->private_data = indio_dev;



	return iio_chrdev_buffer_open(indio_dev);

	ret = iio_chrdev_buffer_open(indio_dev);

	if (ret < 0)

		clear_bit(IIO_BUSY_BIT_POS, &indio_dev->flags);



	return ret;

}



/**
@@ -1093,8 +1102,10 @@ static int iio_chrdev_open(struct inode *inode, struct file *filp) 
 **/

static int iio_chrdev_release(struct inode *inode, struct file *filp)

{

	iio_chrdev_buffer_release(container_of(inode->i_cdev,

					     struct iio_dev, chrdev));

	struct iio_dev *indio_dev = container_of(inode->i_cdev,

						struct iio_dev, chrdev);

	iio_chrdev_buffer_release(indio_dev);

	clear_bit(IIO_BUSY_BIT_POS, &indio_dev->flags);

	return 0;

}