staging:iio:buffering move the copy to user on rip down into implementations

The current interface is not as adaptable as it should be. Moving
this complexity into the implementations makes it easier to add
new implementations.

Signed-off-by: Jonathan Cameron <jic23@cam.ac.uk>
Tested-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 17 insertions, 10 deletions

diff --git a/drivers/staging/iio/ring_sw.c b/drivers/staging/iio/ring_sw.c
index 52624ace0bc5..b71ce3900649 100644
--- a/drivers/staging/iio/ring_sw.c
+++ b/drivers/staging/iio/ring_sw.c
@@ -12,6 +12,7 @@
 #include <linux/module.h>
 #include <linux/device.h>
 #include <linux/workqueue.h>
+#include <linux/poll.h>
 #include "ring_sw.h"
 #include "trigger.h"
 
@@ -152,11 +153,12 @@ error_ret:
 }
 
 int iio_rip_sw_rb(struct iio_ring_buffer *r,
-		  size_t count, u8 **data, int *dead_offset)
+		  size_t count, char __user *buf, int *dead_offset)
 {
 	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;
 
@@ -174,8 +176,8 @@ int iio_rip_sw_rb(struct iio_ring_buffer *r,
 	/* Limit size to whole of ring buffer */
 	bytes_to_rip = min((size_t)(ring->buf.bytes_per_datum*ring->buf.length), count);
 
-	*data = kmalloc(bytes_to_rip, GFP_KERNEL);
-	if (*data == NULL) {
+	data = kmalloc(bytes_to_rip, GFP_KERNEL);
+	if (data == NULL) {
 		ret = -ENOMEM;
 		goto error_ret;
 	}
@@ -204,30 +206,30 @@ int iio_rip_sw_rb(struct iio_ring_buffer *r,
 	if (initial_write_p >= initial_read_p + bytes_to_rip) {
 		/* write_p is greater than necessary, all is easy */
 		max_copied = bytes_to_rip;
-		memcpy(*data, initial_read_p, max_copied);
+		memcpy(data, initial_read_p, max_copied);
 		end_read_p = initial_read_p + max_copied;
 	} else if (initial_write_p > initial_read_p) {
 		/*not enough data to cpy */
 		max_copied = initial_write_p - initial_read_p;
-		memcpy(*data, initial_read_p, max_copied);
+		memcpy(data, initial_read_p, max_copied);
 		end_read_p = initial_write_p;
 	} else {
 		/* going through 'end' of ring buffer */
 		max_copied = ring->data
 			+ ring->buf.length*ring->buf.bytes_per_datum - initial_read_p;
-		memcpy(*data, initial_read_p, max_copied);
+		memcpy(data, initial_read_p, max_copied);
 		/* possible we are done if we align precisely with end */
 		if (max_copied == bytes_to_rip)
 			end_read_p = ring->data;
 		else if (initial_write_p
 			 > ring->data + bytes_to_rip - max_copied) {
 			/* enough data to finish */
-			memcpy(*data + max_copied, ring->data,
+			memcpy(data + max_copied, ring->data,
 			       bytes_to_rip - max_copied);
 			max_copied = bytes_to_rip;
 			end_read_p = ring->data + (bytes_to_rip - max_copied);
 		} else {  /* not enough data */
-			memcpy(*data + max_copied, ring->data,
+			memcpy(data + max_copied, ring->data,
 			       initial_write_p - ring->data);
 			max_copied += initial_write_p - ring->data;
 			end_read_p = initial_write_p;
@@ -264,11 +266,16 @@ int iio_rip_sw_rb(struct iio_ring_buffer *r,
 	while (ring->read_p != end_read_p)
 		ring->read_p = end_read_p;
 
-	return max_copied - *dead_offset;
+	ret = max_copied - *dead_offset;
 
+	if (copy_to_user(buf, data + *dead_offset, ret))  {
+		ret =  -EFAULT;
+		goto error_free_data_cpy;
+	}
 error_free_data_cpy:
-	kfree(*data);
+	kfree(data);
 error_ret:
+
 	return ret;
 }
 EXPORT_SYMBOL(iio_rip_sw_rb);