staging: comedi: pass subdevice to comedi_buf_write_n_allocated()

Change the parameters of `comedi_buf_write_n_allocated()` to pass a
pointer to the comedi subdevice instead of a pointer to the "async"
structure belonging to the subdevice.

The main aim at the moment is to replace all the `struct comedi_async *`
parameters with `struct comedi_subdevice *` parameters in the comedi
driver API.

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

1 files changed, 4 insertions, 2 deletions

diff --git a/drivers/staging/comedi/comedi_buf.c b/drivers/staging/comedi/comedi_buf.c
index 220816857128..ac498e0b4865 100644
--- a/drivers/staging/comedi/comedi_buf.c
+++ b/drivers/staging/comedi/comedi_buf.c
@@ -323,8 +323,10 @@ static unsigned int comedi_buf_munge(struct comedi_async *async,
 	return count;
 }
 
-unsigned int comedi_buf_write_n_allocated(struct comedi_async *async)
+unsigned int comedi_buf_write_n_allocated(struct comedi_subdevice *s)
 {
+	struct comedi_async *async = s->async;
+
 	return async->buf_write_alloc_count - async->buf_write_count;
 }
 
@@ -333,7 +335,7 @@ unsigned int comedi_buf_write_free(struct comedi_subdevice *s,
 				   unsigned int nbytes)
 {
 	struct comedi_async *async = s->async;
-	unsigned int allocated = comedi_buf_write_n_allocated(async);
+	unsigned int allocated = comedi_buf_write_n_allocated(s);
 
 	if (nbytes > allocated)
 		nbytes = allocated;