[PATCH v2 04/12][RESEND] iio: buffer: add index to the first IIO buffer dir and symlink it back

[Alexandru Ardelean <alexandru.ardelean@xxxxxxxxxx>]

This change makes it so that the first buffer directory is named 'buffer0'
and moves the 'scan_elements' under it.

For backwards compatibility these folders are symlinked back to the
original folders.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@xxxxxxxxxx>
---
 drivers/iio/industrialio-buffer.c | 66 +++++++++++++++++++++----------
 1 file changed, 46 insertions(+), 20 deletions(-)

diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c
index 0f470d902790..628d78125126 100644
--- a/drivers/iio/industrialio-buffer.c
+++ b/drivers/iio/industrialio-buffer.c
@@ -1369,7 +1369,8 @@ static void iio_sysfs_del_attrs(struct kobject *kobj, struct attribute **ptr)
  * IIO device.
  */
 static int __iio_buffer_alloc_sysfs_and_mask(struct iio_buffer *buffer,
-					     struct iio_dev *indio_dev)
+					     struct iio_dev *indio_dev,
+					     unsigned int idx)
 {
 	struct iio_dev_attr *p;
 	struct attribute **attr;
@@ -1401,7 +1402,7 @@ static int __iio_buffer_alloc_sysfs_and_mask(struct iio_buffer *buffer,
 	buffer->buffer_attrs = attr;
 
 	ret = kobject_init_and_add(&buffer->buffer_dir, &iio_buffer_dir_ktype,
-				   &indio_dev->dev.kobj, "buffer");
+				   &indio_dev->dev.kobj, "buffer%u", idx);
 	if (ret)
 		goto error_buffer_free_attrs;
 
@@ -1446,7 +1447,7 @@ static int __iio_buffer_alloc_sysfs_and_mask(struct iio_buffer *buffer,
 	}
 
 	ret = kobject_init_and_add(&buffer->scan_el_dir, &iio_scan_el_dir_ktype,
-				   &indio_dev->dev.kobj, "scan_elements");
+				   &buffer->buffer_dir, "scan_elements");
 	if (ret)
 		goto error_free_scan_attrs;
 
@@ -1477,6 +1478,22 @@ static int __iio_buffer_alloc_sysfs_and_mask(struct iio_buffer *buffer,
 	return ret;
 }
 
+/**
+ * __iio_buffer_free_sysfs_and_mask() - Free sysfs objects for a single IIO buffer
+ * @buffer: the iio buffer for which to destroy the objects
+ */
+static void __iio_buffer_free_sysfs_and_mask(struct iio_buffer *buffer)
+{
+	iio_sysfs_del_attrs(&buffer->scan_el_dir, buffer->scan_el_attrs);
+	kobject_put(&buffer->scan_el_dir);
+	kfree(buffer->scan_el_attrs);
+	bitmap_free(buffer->scan_mask);
+	iio_sysfs_del_attrs(&buffer->buffer_dir, buffer->buffer_attrs);
+	iio_free_chan_devattr_list(&buffer->scan_el_dev_attr_list);
+	kobject_put(&buffer->buffer_dir);
+	kfree(buffer->buffer_attrs);
+}
+
 /**
  * iio_buffer_alloc_sysfs_and_mask() - Allocate sysfs attributes to attached buffers
  * @indio_dev: the iio device for which to create the buffer sysfs attributes
@@ -1492,7 +1509,7 @@ int iio_buffer_alloc_sysfs_and_mask(struct iio_dev *indio_dev)
 {
 	struct iio_buffer *buffer = indio_dev->buffer;
 	const struct iio_chan_spec *channels;
-	int i;
+	int i, ret;
 
 	channels = indio_dev->channels;
 	if (channels) {
@@ -1506,23 +1523,29 @@ int iio_buffer_alloc_sysfs_and_mask(struct iio_dev *indio_dev)
 	if (!buffer)
 		return 0;
 
-	return __iio_buffer_alloc_sysfs_and_mask(buffer, indio_dev);
-}
+	ret = __iio_buffer_alloc_sysfs_and_mask(buffer, indio_dev, 0);
+	if (ret)
+		return ret;
 
-/**
- * __iio_buffer_free_sysfs_and_mask() - Free sysfs objects for a single IIO buffer
- * @buffer: the iio buffer for which to destroy the objects
- */
-static void __iio_buffer_free_sysfs_and_mask(struct iio_buffer *buffer)
-{
-	iio_sysfs_del_attrs(&buffer->scan_el_dir, buffer->scan_el_attrs);
-	kobject_put(&buffer->scan_el_dir);
-	kfree(buffer->scan_el_attrs);
-	bitmap_free(buffer->scan_mask);
-	iio_sysfs_del_attrs(&buffer->buffer_dir, buffer->buffer_attrs);
-	iio_free_chan_devattr_list(&buffer->scan_el_dev_attr_list);
-	kobject_put(&buffer->buffer_dir);
-	kfree(buffer->buffer_attrs);
+	ret = sysfs_create_link(&indio_dev->dev.kobj,
+				&indio_dev->buffer->buffer_dir,
+				"buffer");
+	if (ret)
+		goto error_free_sysfs_and_mask;
+
+	ret = sysfs_create_link(&indio_dev->dev.kobj,
+				&indio_dev->buffer->scan_el_dir,
+				"scan_elements");
+	if (ret)
+		goto error_remove_buffer_dir_link;
+
+	return 0;
+
+error_remove_buffer_dir_link:
+	sysfs_remove_link(&indio_dev->dev.kobj, "buffer");
+error_free_sysfs_and_mask:
+	__iio_buffer_free_sysfs_and_mask(buffer);
+	return ret;
 }
 
 /**
@@ -1538,6 +1561,9 @@ void iio_buffer_free_sysfs_and_mask(struct iio_dev *indio_dev)
 	if (!buffer)
 		return;
 
+	sysfs_remove_link(&indio_dev->dev.kobj, "scan_elements");
+	sysfs_remove_link(&indio_dev->dev.kobj, "buffer");
+
 	__iio_buffer_free_sysfs_and_mask(buffer);
 }
 
-- 
2.17.1