staging: comedi: pass subdevice to comedi_buf_read_alloc()

Change the parameters of `comedi_buf_read_alloc()` 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

@@ -370,9 +370,10 @@ unsigned int comedi_buf_read_n_available(struct comedi_async *async)
 EXPORT_SYMBOL_GPL(comedi_buf_read_n_available);
 
 /* allocates a chunk for the reader from filled (and munged) buffer space */
-unsigned int comedi_buf_read_alloc(struct comedi_async *async,
+unsigned int comedi_buf_read_alloc(struct comedi_subdevice *s,
 				   unsigned int nbytes)
 {
+	struct comedi_async *async = s->async;
 	unsigned int available;
 
 	available = async->munge_count - async->buf_read_alloc_count;
@@ -441,7 +442,7 @@ int comedi_buf_get(struct comedi_subdevice *s, unsigned short *x)
 
 	if (n < sizeof(short))
 		return 0;
-	comedi_buf_read_alloc(async, sizeof(short));
+	comedi_buf_read_alloc(s, sizeof(short));
 	*x = *(unsigned short *)(async->prealloc_buf + async->buf_read_ptr);
 	comedi_buf_read_free(async, sizeof(short));
 	return 1;

drivers/staging/comedi/comedi_fops.c

@@ -993,7 +993,7 @@ static int do_bufinfo_ioctl(struct comedi_device *dev,
 		return -EACCES;
 
 	if (bi.bytes_read && (s->subdev_flags & SDF_CMD_READ)) {
-		bi.bytes_read = comedi_buf_read_alloc(async, bi.bytes_read);
+		bi.bytes_read = comedi_buf_read_alloc(s, bi.bytes_read);
 		comedi_buf_read_free(async, bi.bytes_read);
 
 		if (comedi_is_subdevice_idle(s) &&
@@ -2272,7 +2272,7 @@ static ssize_t comedi_read(struct file *file, char __user *buf, size_t nbytes,
 			retval = -EFAULT;
 		}
 
-		comedi_buf_read_alloc(async, n);
+		comedi_buf_read_alloc(s, n);
 		comedi_buf_read_free(async, n);
 
 		count += n;

drivers/staging/comedi/comedidev.h

@@ -340,7 +340,7 @@ 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_alloc(struct comedi_async *, unsigned int);
+unsigned int comedi_buf_read_alloc(struct comedi_subdevice *s, unsigned int n);
 unsigned int comedi_buf_read_free(struct comedi_async *, unsigned int);
 
 int comedi_buf_put(struct comedi_subdevice *s, unsigned short x);

drivers/staging/comedi/drivers/comedi_fc.c

@@ -91,7 +91,7 @@ unsigned int cfc_read_array_from_buffer(struct comedi_subdevice *s,
 	if (num_bytes == 0)
 		return 0;
 
-	num_bytes = comedi_buf_read_alloc(async, num_bytes);
+	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);
 	cfc_inc_scan_progress(s, num_bytes);

drivers/staging/comedi/drivers/mite.c

@@ -560,15 +560,15 @@ EXPORT_SYMBOL_GPL(mite_sync_input_dma);
 int mite_sync_output_dma(struct mite_channel *mite_chan,
 			 struct comedi_async *async)
 {
+	struct comedi_subdevice *s = async->subdevice;
 	int count;
 	u32 nbytes_ub, nbytes_lb;
 	unsigned int old_alloc_count;
-	u32 stop_count =
-	    async->cmd.stop_arg * cfc_bytes_per_scan(async->subdevice);
+	u32 stop_count = async->cmd.stop_arg * cfc_bytes_per_scan(s);
 
 	old_alloc_count = async->buf_read_alloc_count;
 	/*  read alloc as much as we can */
-	comedi_buf_read_alloc(async, async->prealloc_bufsz);
+	comedi_buf_read_alloc(s, async->prealloc_bufsz);
 	nbytes_lb = mite_bytes_read_from_memory_lb(mite_chan);
 	if (async->cmd.stop_src == TRIG_COUNT &&
 	    (int)(nbytes_lb - stop_count) > 0)

drivers/staging/comedi/drivers/ni_mio_common.c

@@ -1545,7 +1545,7 @@ static int ni_ao_setup_MITE_dma(struct comedi_device *dev)
 		return retval;
 
 	/* read alloc the entire buffer */
-	comedi_buf_read_alloc(s->async, s->async->prealloc_bufsz);
+	comedi_buf_read_alloc(s, s->async->prealloc_bufsz);
 
 	spin_lock_irqsave(&devpriv->mite_channel_lock, flags);
 	if (devpriv->ao_mite_chan) {
@@ -3565,7 +3565,7 @@ static int ni_cdo_inttrig(struct comedi_device *dev,
 	s->async->inttrig = NULL;
 
 	/* read alloc the entire buffer */
-	comedi_buf_read_alloc(s->async, s->async->prealloc_bufsz);
+	comedi_buf_read_alloc(s, s->async->prealloc_bufsz);
 
 #ifdef PCIDMA
 	spin_lock_irqsave(&devpriv->mite_channel_lock, flags);