staging: comedi: have comedi_set_spriv() allocate the memory

As suggested by Ian Abbott, comedi_set_spriv() can only be used to
set the subdevice->private pointer to something that can be kfree()'d.
Rename the function to comedi_alloc_spriv() and have it kzalloc() the
memory as well as set the private pointer. This saves a function call
in the drivers and avoids the possibility of incorrectly calling
comedi_set_spriv() for some pointer that is not meant to be kfree()'d.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 8 insertions, 6 deletions

diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c
index 423f882416d9..0794aacc928a 100644
--- a/drivers/staging/comedi/comedi_fops.c
+++ b/drivers/staging/comedi/comedi_fops.c
@@ -532,19 +532,21 @@ static bool comedi_is_subdevice_idle(struct comedi_subdevice *s)
 }
 
 /**
- * comedi_set_spriv() - Set the subdevice private data pointer.
+ * comedi_alloc_spriv() - Allocate memory for the subdevice private data.
  * @s: comedi_subdevice struct
- * @data: pointer to the private data
+ * @size: size of the memory to allocate
  *
  * This also sets the subdevice runflags to allow the core to automatically
  * free the private data during the detach.
  */
-void comedi_set_spriv(struct comedi_subdevice *s, void *data)
+void *comedi_alloc_spriv(struct comedi_subdevice *s, size_t size)
 {
-	s->private = data;
-	comedi_set_subdevice_runflags(s, ~0, SRF_FREE_SPRIV);
+	s->private = kzalloc(size, GFP_KERNEL);
+	if (s->private)
+		comedi_set_subdevice_runflags(s, ~0, SRF_FREE_SPRIV);
+	return s->private;
 }
-EXPORT_SYMBOL_GPL(comedi_set_spriv);
+EXPORT_SYMBOL_GPL(comedi_alloc_spriv);
 
 /*
    This function restores a subdevice to an idle state.