staging: comedi: pass subdevice to comedi_buf_read_n_available()

Change the parameters of `comedi_buf_read_n_available()` 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

@@ -350,8 +350,9 @@ unsigned int comedi_buf_write_free(struct comedi_subdevice *s,
 }
 EXPORT_SYMBOL_GPL(comedi_buf_write_free);
 
-unsigned int comedi_buf_read_n_available(struct comedi_async *async)
+unsigned int comedi_buf_read_n_available(struct comedi_subdevice *s)
 {
+	struct comedi_async *async = s->async;
 	unsigned num_bytes;
 
 	if (!async)
@@ -439,7 +440,7 @@ EXPORT_SYMBOL_GPL(comedi_buf_put);
 int comedi_buf_get(struct comedi_subdevice *s, unsigned short *x)
 {
 	struct comedi_async *async = s->async;
-	unsigned int n = comedi_buf_read_n_available(async);
+	unsigned int n = comedi_buf_read_n_available(s);
 
 	if (n < sizeof(short))
 		return 0;

drivers/staging/comedi/comedi_fops.c

@@ -2029,7 +2029,7 @@ static unsigned int comedi_poll(struct file *file, poll_table *wait)
 	if (s && s->async) {
 		poll_wait(file, &s->async->wait_head, wait);
 		if (!s->busy || !comedi_is_subdevice_running(s) ||
-		    comedi_buf_read_n_available(s->async) > 0)
+		    comedi_buf_read_n_available(s) > 0)
 			mask |= POLLIN | POLLRDNORM;
 	}
 
@@ -2229,7 +2229,7 @@ static ssize_t comedi_read(struct file *file, char __user *buf, size_t nbytes,
 
 		n = nbytes;
 
-		m = comedi_buf_read_n_available(async);
+		m = comedi_buf_read_n_available(s);
 		/* printk("%d available\n",m); */
 		if (async->buf_read_ptr + m > async->prealloc_bufsz)
 			m = async->prealloc_bufsz - async->buf_read_ptr;

drivers/staging/comedi/comedidev.h

@@ -339,7 +339,7 @@ int comedi_set_hw_dev(struct comedi_device *dev, struct device *hw_dev);
 unsigned int comedi_buf_write_alloc(struct comedi_subdevice *s, unsigned int n);
 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_n_available(struct comedi_subdevice *s);
 unsigned int comedi_buf_read_alloc(struct comedi_subdevice *s, unsigned int n);
 unsigned int comedi_buf_read_free(struct comedi_subdevice *s, unsigned int n);
 

drivers/staging/comedi/drivers/amplc_pci224.c

@@ -558,7 +558,7 @@ static void pci224_ao_handle_fifo(struct comedi_device *dev,
 		bytes_per_scan = sizeof(short);
 	}
 	/* Determine number of scans available in buffer. */
-	num_scans = comedi_buf_read_n_available(s->async) / bytes_per_scan;
+	num_scans = comedi_buf_read_n_available(s) / bytes_per_scan;
 	if (cmd->stop_src == TRIG_COUNT) {
 		/* Fixed number of scans. */
 		if (num_scans > devpriv->ao_stop_count)

drivers/staging/comedi/drivers/amplc_pci230.c

@@ -1205,7 +1205,7 @@ static int pci230_handle_ao_fifo(struct comedi_device *dev,
 	dacstat = inw(dev->iobase + PCI230_DACCON);
 	/* Determine number of scans available in buffer. */
 	bytes_per_scan = cmd->chanlist_len * sizeof(short);
-	num_scans = comedi_buf_read_n_available(async) / bytes_per_scan;
+	num_scans = comedi_buf_read_n_available(s) / bytes_per_scan;
 	if (cmd->stop_src == TRIG_COUNT) {
 		/* Fixed number of scans. */
 		if (num_scans > devpriv->ao_scan_count)

drivers/staging/comedi/drivers/cb_pcidas64.c

@@ -2893,7 +2893,7 @@ static unsigned int load_ao_dma_buffer(struct comedi_device *dev,
 	buffer_index = devpriv->ao_dma_index;
 	prev_buffer_index = prev_ao_dma_index(dev);
 
-	num_bytes = comedi_buf_read_n_available(dev->write_subdev->async);
+	num_bytes = comedi_buf_read_n_available(dev->write_subdev);
 	if (num_bytes > DMA_BUFFER_SIZE)
 		num_bytes = DMA_BUFFER_SIZE;
 	if (cmd->stop_src == TRIG_COUNT && num_bytes > devpriv->ao_count)

drivers/staging/comedi/drivers/ni_660x.c

@@ -825,7 +825,7 @@ static int ni_660x_input_poll(struct comedi_device *dev,
 	spin_lock_irqsave(&devpriv->interrupt_lock, flags);
 	mite_sync_input_dma(counter->mite_chan, s->async);
 	spin_unlock_irqrestore(&devpriv->interrupt_lock, flags);
-	return comedi_buf_read_n_available(s->async);
+	return comedi_buf_read_n_available(s);
 }
 
 static int ni_660x_buf_change(struct comedi_device *dev,

drivers/staging/comedi/drivers/ni_mio_common.c

@@ -1200,7 +1200,7 @@ static int ni_ao_fifo_half_empty(struct comedi_device *dev,
 	const struct ni_board_struct *board = comedi_board(dev);
 	int n;
 
-	n = comedi_buf_read_n_available(s->async);
+	n = comedi_buf_read_n_available(s);
 	if (n == 0) {
 		s->async->events |= COMEDI_CB_OVERFLOW;
 		return 0;
@@ -1230,7 +1230,7 @@ static int ni_ao_prep_fifo(struct comedi_device *dev,
 		ni_ao_win_outl(dev, 0x6, AO_FIFO_Offset_Load_611x);
 
 	/* load some data */
-	n = comedi_buf_read_n_available(s->async);
+	n = comedi_buf_read_n_available(s);
 	if (n == 0)
 		return 0;