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staging: comedi: use file->private_data in file operations

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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: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Ian Abbott
2013-11-08 15:03:40 +00:00
committed by Greg Kroah-Hartman
parent 69e2387f3b
commit e5d670dcb7
1 changed files with 8 additions and 30 deletions
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38
drivers/staging/comedi/comedi_fops.c
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@@ -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 @@ ok:
}
dev->use_count++;
file->private_data = dev;
rc = 0;
out:
@@ -2435,25 +2421,17 @@ out:
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) {