staging: comedi: don't hijack hardware device private data
commit c43435d7722134ed1fda58ce1025f41029bd58ad upstream.
comedi_auto_config() associates a Comedi minor device number with an
auto-configured hardware device and comedi_auto_unconfig() disassociates
it. Currently, these use the hardware device's private data pointer to
point to some allocated storage holding the minor device number. This
is a bit of a waste of the hardware device's private data pointer,
preventing it from being used for something more useful by the low-level
comedi device drivers. For example, it would make more sense if
comedi_usb_auto_config() was passed a pointer to the struct
usb_interface instead of the struct usb_device, but this cannot be done
currently because the low-level comedi drivers already use the private
data pointer in the struct usb_interface for something more useful.
This patch stops the comedi core hijacking the hardware device's private
data pointer. Instead, comedi_auto_config() stores a pointer to the
hardware device's struct device in the struct comedi_device_file_info
associated with the minor device number, and comedi_auto_unconfig()
calls new function comedi_find_board_minor() to recover the minor device
number associated with the hardware device.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c
index 3fd9772..b67c107 100644
--- a/drivers/staging/comedi/comedi_fops.c
+++ b/drivers/staging/comedi/comedi_fops.c
@@ -2210,6 +2210,7 @@
kfree(info);
return -ENOMEM;
}
+ info->hardware_device = hardware_device;
comedi_device_init(info->device);
spin_lock_irqsave(&comedi_file_info_table_lock, flags);
for (i = 0; i < COMEDI_NUM_BOARD_MINORS; ++i) {
@@ -2298,6 +2299,23 @@
}
}
+int comedi_find_board_minor(struct device *hardware_device)
+{
+ int minor;
+ struct comedi_device_file_info *info;
+
+ for (minor = 0; minor < COMEDI_NUM_BOARD_MINORS; minor++) {
+ spin_lock(&comedi_file_info_table_lock);
+ info = comedi_file_info_table[minor];
+ if (info && info->hardware_device == hardware_device) {
+ spin_unlock(&comedi_file_info_table_lock);
+ return minor;
+ }
+ spin_unlock(&comedi_file_info_table_lock);
+ }
+ return -ENODEV;
+}
+
int comedi_alloc_subdevice_minor(struct comedi_device *dev,
struct comedi_subdevice *s)
{