staging:iio:buffering remove unused parameter dead_offset from read_last_n in all buffer implementations.

This element has been usused by the core for quite some time.  sca3000 set it none the less
until the rewrite in the previous patch (and hence didn't work).

Signed-off-by: Jonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/iio/accel/sca3000_ring.c

@@ -79,16 +79,13 @@ static int sca3000_read_data(struct sca3000_state *st,
  * @r:			the ring
  * @count:		number of samples to try and pull
  * @data:		output the actual samples pulled from the hw ring
- * @dead_offset:	cheating a bit here: Set to 1 so as to allow for the
- *			leading byte used in bus comms.
  *
  * Currently does not provide timestamps.  As the hardware doesn't add them they
  * can only be inferred approximately from ring buffer events such as 50% full
  * and knowledge of when buffer was last emptied.  This is left to userspace.
  **/
 static int sca3000_read_first_n_hw_rb(struct iio_ring_buffer *r,
-				      size_t count, char __user *buf,
-				      int *dead_offset)
+				      size_t count, char __user *buf)
 {
 	struct iio_hw_ring_buffer *hw_ring = iio_to_hw_ring_buf(r);
 	struct iio_dev *indio_dev = hw_ring->private;

drivers/staging/iio/industrialio-ring.c

@@ -71,12 +71,12 @@ static ssize_t iio_ring_read_first_n_outer(struct file *filp, char __user *buf,
 				  size_t n, loff_t *f_ps)
 {
 	struct iio_ring_buffer *rb = filp->private_data;
-	int ret, dead_offset;
+	int ret;
 
 	/* rip lots must exist. */
 	if (!rb->access.read_first_n)
 		return -EINVAL;
-	ret = rb->access.read_first_n(rb, n, buf, &dead_offset);
+	ret = rb->access.read_first_n(rb, n, buf);
 
 	return ret;
 }

drivers/staging/iio/kfifo_buf.c

@@ -182,12 +182,11 @@ int iio_store_to_kfifo(struct iio_ring_buffer *r, u8 *data, s64 timestamp)
 EXPORT_SYMBOL(iio_store_to_kfifo);
 
 int iio_read_first_n_kfifo(struct iio_ring_buffer *r,
-			   size_t n, char __user *buf, int *deadoffset)
+			   size_t n, char __user *buf)
 {
 	int ret, copied;
 	struct iio_kfifo *kf = iio_to_kfifo(r);
 
-	*deadoffset = 0;
 	ret = kfifo_to_user(&kf->kf, buf, r->bytes_per_datum*n, &copied);
 
 	return copied;

drivers/staging/iio/kfifo_buf.h

@@ -23,8 +23,7 @@ void iio_unmark_kfifo_in_use(struct iio_ring_buffer *r);
 int iio_store_to_kfifo(struct iio_ring_buffer *r, u8 *data, s64 timestamp);
 int iio_read_first_n_kfifo(struct iio_ring_buffer *r,
 			   size_t n,
-			   char __user *buf,
-			   int *dead_offset);
+			   char __user *buf);
 
 int iio_request_update_kfifo(struct iio_ring_buffer *r);
 int iio_mark_update_needed_kfifo(struct iio_ring_buffer *r);

drivers/staging/iio/ring_generic.h

@@ -50,8 +50,7 @@ struct iio_ring_access_funcs {
 	int (*read_last)(struct iio_ring_buffer *ring, u8 *data);
 	int (*read_first_n)(struct iio_ring_buffer *ring,
 			    size_t n,
-			    char __user *buf,
-			    int *dead_offset);
+			    char __user *buf);
 
 	int (*mark_param_change)(struct iio_ring_buffer *ring);
 	int (*request_update)(struct iio_ring_buffer *ring);

drivers/staging/iio/ring_sw.c

@@ -139,14 +139,13 @@ static int iio_store_to_sw_ring(struct iio_sw_ring_buffer *ring,
 }
 
 int iio_read_first_n_sw_rb(struct iio_ring_buffer *r,
-			   size_t n, char __user *buf, int *dead_offset)
+			   size_t n, char __user *buf)
 {
 	struct iio_sw_ring_buffer *ring = iio_to_sw_ring(r);
 
 	u8 *initial_read_p, *initial_write_p, *current_read_p, *end_read_p;
 	u8 *data;
-	int ret, max_copied;
-	int bytes_to_rip;
+	int ret, max_copied, bytes_to_rip, dead_offset;
 
 	/* A userspace program has probably made an error if it tries to
 	 *  read something that is not a whole number of bpds.
@@ -227,9 +226,9 @@ int iio_read_first_n_sw_rb(struct iio_ring_buffer *r,
 	current_read_p = ring->read_p;
 
 	if (initial_read_p <= current_read_p)
-		*dead_offset = current_read_p - initial_read_p;
+		dead_offset = current_read_p - initial_read_p;
 	else
-		*dead_offset = ring->buf.length*ring->buf.bytes_per_datum
+		dead_offset = ring->buf.length*ring->buf.bytes_per_datum
 			- (initial_read_p - current_read_p);
 
 	/* possible issue if the initial write has been lapped or indeed
@@ -237,7 +236,7 @@ int iio_read_first_n_sw_rb(struct iio_ring_buffer *r,
 	/* No valid data read.
 	 * In this case the read pointer is already correct having been
 	 * pushed further than we would look. */
-	if (max_copied - *dead_offset < 0) {
+	if (max_copied - dead_offset < 0) {
 		ret = 0;
 		goto error_free_data_cpy;
 	}
@@ -253,9 +252,9 @@ int iio_read_first_n_sw_rb(struct iio_ring_buffer *r,
 	while (ring->read_p != end_read_p)
 		ring->read_p = end_read_p;
 
-	ret = max_copied - *dead_offset;
+	ret = max_copied - dead_offset;
 
-	if (copy_to_user(buf, data + *dead_offset, ret))  {
+	if (copy_to_user(buf, data + dead_offset, ret))  {
 		ret =  -EFAULT;
 		goto error_free_data_cpy;
 	}

drivers/staging/iio/ring_sw.h

@@ -97,13 +97,11 @@ int iio_store_to_sw_rb(struct iio_ring_buffer *r, u8 *data, s64 timestamp);
  * @r:			ring buffer instance
  * @n:			number of datum's to try and read
  * @buf:		userspace buffer into which data is copied
- * @dead_offset:	how much of the stored data was possibly invalidated by
  *			the end of the copy.
  **/
 int iio_read_first_n_sw_rb(struct iio_ring_buffer *r,
 			   size_t n,
-			   char __user *buf,
-			   int *dead_offset);
+			   char __user *buf);
 
 /**
  * iio_request_update_sw_rb() - update params if update needed