staging: comedi: pass subdevice to comedi_buf_read_free()

Change the parameters of `comedi_buf_read_free()` 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

@@ -398,9 +398,10 @@ static unsigned int comedi_buf_read_n_allocated(struct comedi_async *async)
 }
 
 /* transfers control of a chunk from reader to free buffer space */
-unsigned int comedi_buf_read_free(struct comedi_async *async,
+unsigned int comedi_buf_read_free(struct comedi_subdevice *s,
 				  unsigned int nbytes)
 {
+	struct comedi_async *async = s->async;
 	unsigned int allocated;
 
 	/*
@@ -444,7 +445,7 @@ int comedi_buf_get(struct comedi_subdevice *s, unsigned short *x)
 		return 0;
 	comedi_buf_read_alloc(s, sizeof(short));
 	*x = *(unsigned short *)(async->prealloc_buf + async->buf_read_ptr);
-	comedi_buf_read_free(async, sizeof(short));
+	comedi_buf_read_free(s, sizeof(short));
 	return 1;
 }
 EXPORT_SYMBOL_GPL(comedi_buf_get);

drivers/staging/comedi/comedi_fops.c

@@ -994,7 +994,7 @@ static int do_bufinfo_ioctl(struct comedi_device *dev,
 
 	if (bi.bytes_read && (s->subdev_flags & SDF_CMD_READ)) {
 		bi.bytes_read = comedi_buf_read_alloc(s, bi.bytes_read);
-		comedi_buf_read_free(async, bi.bytes_read);
+		comedi_buf_read_free(s, bi.bytes_read);
 
 		if (comedi_is_subdevice_idle(s) &&
 		    async->buf_write_count == async->buf_read_count) {
@@ -2273,7 +2273,7 @@ static ssize_t comedi_read(struct file *file, char __user *buf, size_t nbytes,
 		}
 
 		comedi_buf_read_alloc(s, n);
-		comedi_buf_read_free(async, n);
+		comedi_buf_read_free(s, n);
 
 		count += n;
 		nbytes -= n;

drivers/staging/comedi/comedidev.h

@@ -341,7 +341,7 @@ unsigned int comedi_buf_write_free(struct comedi_subdevice *s, unsigned int n);
 
 unsigned int comedi_buf_read_n_available(struct comedi_async *);
 unsigned int comedi_buf_read_alloc(struct comedi_subdevice *s, unsigned int n);
-unsigned int comedi_buf_read_free(struct comedi_async *, unsigned int);
+unsigned int comedi_buf_read_free(struct comedi_subdevice *s, unsigned int n);
 
 int comedi_buf_put(struct comedi_subdevice *s, unsigned short x);
 int comedi_buf_get(struct comedi_subdevice *s, unsigned short *x);

drivers/staging/comedi/drivers/comedi_fc.c

@@ -86,16 +86,14 @@ EXPORT_SYMBOL_GPL(cfc_write_array_to_buffer);
 unsigned int cfc_read_array_from_buffer(struct comedi_subdevice *s,
 					void *data, unsigned int num_bytes)
 {
-	struct comedi_async *async = s->async;
-
 	if (num_bytes == 0)
 		return 0;
 
 	num_bytes = comedi_buf_read_alloc(s, num_bytes);
 	comedi_buf_memcpy_from(s, 0, data, num_bytes);
-	comedi_buf_read_free(async, num_bytes);
+	comedi_buf_read_free(s, num_bytes);
 	cfc_inc_scan_progress(s, num_bytes);
-	async->events |= COMEDI_CB_BLOCK;
+	s->async->events |= COMEDI_CB_BLOCK;
 
 	return num_bytes;
 }

drivers/staging/comedi/drivers/mite.c

@@ -588,7 +588,7 @@ int mite_sync_output_dma(struct mite_channel *mite_chan,
 		return 0;
 
 	if (count) {
-		comedi_buf_read_free(async, count);
+		comedi_buf_read_free(s, count);
 		async->events |= COMEDI_CB_BLOCK;
 	}
 	return 0;