On 2/15/21 11:40 AM, Alexandru Ardelean wrote:
[...]
/**
* iio_buffer_wakeup_poll - Wakes up the buffer waitqueue
* @indio_dev: The IIO device
@@ -1343,6 +1371,96 @@ static void iio_buffer_unregister_legacy_sysfs_groups(struct iio_dev *indio_dev)
kfree(iio_dev_opaque->legacy_scan_el_group.attrs);
}
[...]
+static long iio_device_buffer_getfd(struct iio_dev *indio_dev, unsigned long arg)
+{
+ struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
+ int __user *ival = (int __user *)arg;
+ struct iio_dev_buffer_pair *ib;
+ struct iio_buffer *buffer;
+ int fd, idx, ret;
+
+ if (copy_from_user(&idx, ival, sizeof(idx)))
+ return -EFAULT;
If we only want to pass an int, we can pass that directly, no need to
pass it as a pointer.
int fd = arg;
+
+ if (idx >= iio_dev_opaque->attached_buffers_cnt)
+ return -ENODEV;
+
+ iio_device_get(indio_dev);
+
+ buffer = iio_dev_opaque->attached_buffers[idx];
+
+ if (test_and_set_bit(IIO_BUSY_BIT_POS, &buffer->flags)) {
+ ret = -EBUSY;
+ goto error_iio_dev_put;
+ }
+
+ ib = kzalloc(sizeof(*ib), GFP_KERNEL);
+ if (!ib) {
+ ret = -ENOMEM;
+ goto error_clear_busy_bit;
+ }
+
+ ib->indio_dev = indio_dev;
+ ib->buffer = buffer;
+
+ fd = anon_inode_getfd("iio:buffer", &iio_buffer_chrdev_fileops,
+ ib, O_RDWR | O_CLOEXEC);
I wonder if we need to allow to pass flags, like e.g. O_NONBLOCK.
Something like
https://elixir.bootlin.com/linux/latest/source/fs/signalfd.c#L288
+ if (fd < 0) {
+ ret = fd;
+ goto error_free_ib;
+ }
+
+ if (copy_to_user(ival, &fd, sizeof(fd))) {
+ put_unused_fd(fd);
+ ret = -EFAULT;
+ goto error_free_ib;
+ }
Here we copy back the fd, but also return it. Just return is probably
enough.
+
+ return fd;
+
+error_free_ib:
+ kfree(ib);
+error_clear_busy_bit:
+ clear_bit(IIO_BUSY_BIT_POS, &buffer->flags);
+error_iio_dev_put:
+ iio_device_put(indio_dev);
+ return ret;
+}
[...]
diff --git a/include/linux/iio/iio-opaque.h b/include/linux/iio/iio-opaque.h
index b6ebc04af3e7..32addd5e790e 100644
--- a/include/linux/iio/iio-opaque.h
+++ b/include/linux/iio/iio-opaque.h
@@ -9,6 +9,7 @@
* @event_interface: event chrdevs associated with interrupt lines
* @attached_buffers: array of buffers statically attached by the driver
* @attached_buffers_cnt: number of buffers in the array of statically attached buffers
+ * @buffer_ioctl_handler: ioctl() handler for this IIO device's buffer interface
* @buffer_list: list of all buffers currently attached
* @channel_attr_list: keep track of automatically created channel
* attributes
@@ -28,6 +29,7 @@ struct iio_dev_opaque {
struct iio_event_interface *event_interface;
struct iio_buffer **attached_buffers;
unsigned int attached_buffers_cnt;
+ struct iio_ioctl_handler *buffer_ioctl_handler;
Can we just embedded this struct so we do not have to
allocate/deallocate it?
struct list_head buffer_list;
struct list_head channel_attr_list;
struct attribute_group chan_attr_group;
