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Commit 8d92db28 authored by Lars-Peter Clausen's avatar Lars-Peter Clausen Committed by Jonathan Cameron
Browse files

iio: buffer: Make length attribute read only for buffers without set_length 



If a buffer implementation does not implement the set_length() callback the
length will be static and can not be changed by userspace. Mark the length
attribute as a read only property in this case so userspace is aware of this
rather than just silently accepting any length value.

Signed-off-by: default avatarLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: default avatarJonathan Cameron <jic23@kernel.org>
parent 08e7e0ad

drivers/iio/industrialio-buffer.c

+7 −3
Original line number Diff line number Diff line
@@ -418,7 +418,6 @@ static ssize_t iio_buffer_write_length(struct device *dev, 
	if (iio_buffer_is_active(indio_dev->buffer)) {

		ret = -EBUSY;

	} else {

		if (buffer->access->set_length)

		buffer->access->set_length(buffer, val);

		ret = 0;

	}
@@ -760,6 +759,8 @@ static const char * const iio_scan_elements_group_name = "scan_elements"; 


static DEVICE_ATTR(length, S_IRUGO | S_IWUSR, iio_buffer_read_length,

		   iio_buffer_write_length);

static struct device_attribute dev_attr_length_ro = __ATTR(length,

	S_IRUGO, iio_buffer_read_length, NULL);

static DEVICE_ATTR(enable, S_IRUGO | S_IWUSR,

		   iio_buffer_show_enable, iio_buffer_store_enable);
@@ -786,7 +787,10 @@ int iio_buffer_alloc_sysfs_and_mask(struct iio_dev *indio_dev) 
	if (!buffer->buffer_group.attrs)

		return -ENOMEM;



	if (buffer->access->set_length)

		buffer->buffer_group.attrs[0] = &dev_attr_length.attr;

	else

		buffer->buffer_group.attrs[0] = &dev_attr_length_ro.attr;

	buffer->buffer_group.attrs[1] = &dev_attr_enable.attr;

	if (buffer->attrs)

		memcpy(&buffer->buffer_group.attrs[2], buffer->attrs,