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staging: comedi: (core): add comedi_dev_from_file_info()

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Setting `info = comedi_file_info_from_minor(minor)` and `dev =
comedi_dev_from_minor(minor)` in the same function is a bit of a waste.
The latter function is just a call of the former followed by a
conditional return of an embedded pointer (`info->device`) or NULL.  The
former function uses a spin-lock which is where the wastfulness comes
in.

Move the "followed by a conditional return of an embedded pointer" part
into a new function `comedi_dev_from_file_info` and call this instead of
`comedi_dev_from_minor()` in the places where
`comedi_file_info_from_minor()` is also called.

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 2013-01-08 13:27:48 +00:00 • committed by Greg Kroah-Hartman
parent a679f36152
commit ba1bcf6f23
1 changed files with 12 additions and 10 deletions
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22
drivers/staging/comedi/comedi_fops.c
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@ -103,13 +103,15 @@ static struct comedi_file_info *comedi_file_info_from_minor(unsigned minor)
return info;
}
static struct comedi_device *
comedi_dev_from_file_info(struct comedi_file_info *info)
{
return info ? info->device : NULL;
}
struct comedi_device *comedi_dev_from_minor(unsigned minor)
{
struct comedi_file_info *info;
info = comedi_file_info_from_minor(minor);
return info ? info->device : NULL;
return comedi_dev_from_file_info(comedi_file_info_from_minor(minor));
}
EXPORT_SYMBOL_GPL(comedi_dev_from_minor);
@ -1647,8 +1649,8 @@ static long comedi_unlocked_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
const unsigned minor = iminor(file->f_dentry->d_inode);
struct comedi_device *dev = comedi_dev_from_minor(minor);
struct comedi_file_info *info = comedi_file_info_from_minor(minor);
struct comedi_device *dev = comedi_dev_from_file_info(info);
int rc;
if (!dev)
@ -1771,7 +1773,7 @@ static int comedi_mmap(struct file *file, struct vm_area_struct *vma)
{
const unsigned minor = iminor(file->f_dentry->d_inode);
struct comedi_file_info *info = comedi_file_info_from_minor(minor);
struct comedi_device *dev = comedi_dev_from_minor(minor);
struct comedi_device *dev = comedi_dev_from_file_info(info);
struct comedi_subdevice *s;
struct comedi_async *async;
unsigned long start = vma->vm_start;
@ -1851,7 +1853,7 @@ static unsigned int comedi_poll(struct file *file, poll_table *wait)
unsigned int mask = 0;
const unsigned minor = iminor(file->f_dentry->d_inode);
struct comedi_file_info *info = comedi_file_info_from_minor(minor);
struct comedi_device *dev = comedi_dev_from_minor(minor);
struct comedi_device *dev = comedi_dev_from_file_info(info);
struct comedi_subdevice *s;
if (!dev)
@ -1897,7 +1899,7 @@ static ssize_t comedi_write(struct file *file, const char __user *buf,
DECLARE_WAITQUEUE(wait, current);
const unsigned minor = iminor(file->f_dentry->d_inode);
struct comedi_file_info *info = comedi_file_info_from_minor(minor);
struct comedi_device *dev = comedi_dev_from_minor(minor);
struct comedi_device *dev = comedi_dev_from_file_info(info);
if (!dev)
return -ENODEV;
@ -1992,7 +1994,7 @@ static ssize_t comedi_read(struct file *file, char __user *buf, size_t nbytes,
DECLARE_WAITQUEUE(wait, current);
const unsigned minor = iminor(file->f_dentry->d_inode);
struct comedi_file_info *info = comedi_file_info_from_minor(minor);
struct comedi_device *dev = comedi_dev_from_minor(minor);
struct comedi_device *dev = comedi_dev_from_file_info(info);
if (!dev)
return -ENODEV;