staging: comedi: pass subdevice to comedi_buf_reset()

Change the parameters of `comedi_buf_reset()` 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>

drivers/staging/comedi/comedi_buf.c

@@ -222,8 +222,10 @@ int comedi_buf_alloc(struct comedi_device *dev, struct comedi_subdevice *s,
 	return 0;
 }
 
-void comedi_buf_reset(struct comedi_async *async)
+void comedi_buf_reset(struct comedi_subdevice *s)
 {
+	struct comedi_async *async = s->async;
+
 	async->buf_write_alloc_count = 0;
 	async->buf_write_count = 0;
 	async->buf_read_alloc_count = 0;

drivers/staging/comedi/comedi_fops.c

@@ -583,7 +583,7 @@ static void do_become_nonbusy(struct comedi_device *dev,
 
 	comedi_set_subdevice_runflags(s, SRF_RUNNING, 0);
 	if (async) {
-		comedi_buf_reset(async);
+		comedi_buf_reset(s);
 		async->inttrig = NULL;
 		kfree(async->cmd.chanlist);
 		async->cmd.chanlist = NULL;
@@ -1557,7 +1557,7 @@ static int do_cmd_ioctl(struct comedi_device *dev,
 		goto cleanup;
 	}
 
-	comedi_buf_reset(async);
+	comedi_buf_reset(s);
 
 	async->cb_mask =
 	    COMEDI_CB_EOA | COMEDI_CB_BLOCK | COMEDI_CB_ERROR |

drivers/staging/comedi/comedi_internal.h

@@ -15,7 +15,7 @@ void comedi_free_subdevice_minor(struct comedi_subdevice *s);
 
 int comedi_buf_alloc(struct comedi_device *dev, struct comedi_subdevice *s,
 		     unsigned long new_size);
-void comedi_buf_reset(struct comedi_async *async);
+void comedi_buf_reset(struct comedi_subdevice *s);
 bool comedi_buf_is_mmapped(struct comedi_async *async);
 void comedi_buf_map_get(struct comedi_buf_map *bm);
 int comedi_buf_map_put(struct comedi_buf_map *bm);