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Commit e5d670dc authored by Ian Abbott's avatar Ian Abbott Committed by Greg Kroah-Hartman
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staging: comedi: use file->private_data in file operations 



Since the `struct comedi_device` should now be protected from being
freed while an open file object is using it, use the `private_data`
member of the `struct file` to point to it.  Set it in `comedi_open()`
and use it in the other file operation handlers instead of calling
`comedi_dev_from_minor()` and checking the result.

Signed-off-by: default avatarIan Abbott <abbotti@mev.co.uk>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 69e2387f

drivers/staging/comedi/comedi_fops.c

+8 −30
Original line number Diff line number Diff line
@@ -1828,12 +1828,9 @@ static long comedi_unlocked_ioctl(struct file *file, unsigned int cmd, 
				  unsigned long arg)

{

	const unsigned minor = iminor(file_inode(file));

	struct comedi_device *dev = comedi_dev_from_minor(minor);

	struct comedi_device *dev = file->private_data;

	int rc;



	if (!dev)

		return -ENODEV;



	mutex_lock(&dev->mutex);



	/* Device config is special, because it must work on
@@ -1964,7 +1961,7 @@ static struct vm_operations_struct comedi_vm_ops = { 
static int comedi_mmap(struct file *file, struct vm_area_struct *vma)

{

	const unsigned minor = iminor(file_inode(file));

	struct comedi_device *dev = comedi_dev_from_minor(minor);

	struct comedi_device *dev = file->private_data;

	struct comedi_subdevice *s;

	struct comedi_async *async;

	unsigned long start = vma->vm_start;
@@ -1973,9 +1970,6 @@ static int comedi_mmap(struct file *file, struct vm_area_struct *vma) 
	int i;

	int retval;



	if (!dev)

		return -ENODEV;



	mutex_lock(&dev->mutex);



	if (!dev->attached) {
@@ -2043,12 +2037,9 @@ static unsigned int comedi_poll(struct file *file, poll_table *wait) 
{

	unsigned int mask = 0;

	const unsigned minor = iminor(file_inode(file));

	struct comedi_device *dev = comedi_dev_from_minor(minor);

	struct comedi_device *dev = file->private_data;

	struct comedi_subdevice *s;



	if (!dev)

		return -ENODEV;



	mutex_lock(&dev->mutex);



	if (!dev->attached) {
@@ -2088,14 +2079,11 @@ static ssize_t comedi_write(struct file *file, const char __user *buf, 
	int n, m, count = 0, retval = 0;

	DECLARE_WAITQUEUE(wait, current);

	const unsigned minor = iminor(file_inode(file));

	struct comedi_device *dev = comedi_dev_from_minor(minor);

	struct comedi_device *dev = file->private_data;

	bool on_wait_queue = false;

	bool attach_locked;

	unsigned int old_detach_count;



	if (!dev)

		return -ENODEV;



	/* Protect against device detachment during operation. */

	down_read(&dev->attach_lock);

	attach_locked = true;
@@ -2227,14 +2215,11 @@ static ssize_t comedi_read(struct file *file, char __user *buf, size_t nbytes, 
	int n, m, count = 0, retval = 0;

	DECLARE_WAITQUEUE(wait, current);

	const unsigned minor = iminor(file_inode(file));

	struct comedi_device *dev = comedi_dev_from_minor(minor);

	struct comedi_device *dev = file->private_data;

	unsigned int old_detach_count;

	bool become_nonbusy = false;

	bool attach_locked;



	if (!dev)

		return -ENODEV;



	/* Protect against device detachment during operation. */

	down_read(&dev->attach_lock);

	attach_locked = true;
@@ -2424,6 +2409,7 @@ static int comedi_open(struct inode *inode, struct file *file) 
	}



	dev->use_count++;

	file->private_data = dev;

	rc = 0;



out:
@@ -2435,25 +2421,17 @@ static int comedi_open(struct inode *inode, struct file *file) 


static int comedi_fasync(int fd, struct file *file, int on)

{

	const unsigned minor = iminor(file_inode(file));

	struct comedi_device *dev = comedi_dev_from_minor(minor);



	if (!dev)

		return -ENODEV;

	struct comedi_device *dev = file->private_data;



	return fasync_helper(fd, file, on, &dev->async_queue);

}



static int comedi_close(struct inode *inode, struct file *file)

{

	const unsigned minor = iminor(inode);

	struct comedi_device *dev = comedi_dev_from_minor(minor);

	struct comedi_device *dev = file->private_data;

	struct comedi_subdevice *s = NULL;

	int i;



	if (!dev)

		return -ENODEV;



	mutex_lock(&dev->mutex);



	if (dev->subdevices) {