redonkable
/
alistair23-linux
1
0
Fork 0
Code Releases Activity

staging: comedi: simplify comedi_set_hw_dev() 

Since `get_device()` and `put_device()` can take a NULL device
parameter, `comedi_set_hw_dev()` can be simplified to always call
`get_device()` for the new, possibly NULL hardware device, and
`put_device()` for the old, possibly NULL hardware device.  As long as
we do it in that order, there shouldn't be any problem with
`kref_release()` getting called unexpectedly when the new hardware
device is the old hardware device.

Simplify `comedi_set_hw_dev()` and update the comment because the
function is used for additional purposes since the old comment was
written.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
hifive-unleashed-5.1
Ian Abbott 2013-01-29 16:20:17 +00:00 committed by Greg Kroah-Hartman
parent 104640606b
commit bc3954b814
1 changed files with 10 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

21
drivers/staging/comedi/comedidev.h
View File

@ -429,20 +429,19 @@ static inline unsigned int bytes_per_sample(const struct comedi_subdevice *subd)
return sizeof(short);
}
/* must be used in attach to set dev->hw_dev if you wish to dma directly
into comedi's buffer */
/*
* Must set dev->hw_dev if you wish to dma directly into comedi's buffer.
* Also useful for retrieving a previously configured hardware device of
* known bus type. Set automatically for auto-configured devices.
* Automatically set to NULL when detaching hardware device.
*/
static inline void comedi_set_hw_dev(struct comedi_device *dev,
struct device *hw_dev)
{
if (dev->hw_dev == hw_dev)
return;
if (dev->hw_dev)
put_device(dev->hw_dev);
dev->hw_dev = hw_dev;
if (dev->hw_dev) {
dev->hw_dev = get_device(dev->hw_dev);
BUG_ON(dev->hw_dev == NULL);
}
struct device *old_hw_dev = dev->hw_dev;
dev->hw_dev = get_device(hw_dev);
put_device(old_hw_dev);
}
static inline struct pci_dev *comedi_to_pci_dev(struct comedi_device *dev)