On Sat, May 1, 2021 at 8:28 PM Jonathan Cameron <jic23@xxxxxxxxxx> wrote:
>
> From: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
>
> Whilst it is almost always possible to arrange for scan data to be
> read directly into a buffer that is suitable for passing to
> iio_push_to_buffers_with_timestamp(), there are a few places where
> leading data needs to be skipped over.
>
> For these cases introduce a function that will allocate an appropriate
> sized and aligned bounce buffer (if not already allocated) and copy
> the unaligned data into that before calling
> iio_push_to_buffers_with_timestamp() on the bounce buffer.
> We tie the lifespace of this buffer to that of the iio_dev.dev
> which should ensure no memory leaks occur.
...
> +/**
> + * iio_push_to_buffers_with_ts_na() - push to registered buffer,
> + * no alignment or space requirements.
> + * @indio_dev: iio_dev structure for device.
> + * @data: channel data excluding the timestamp.
> + * @data_sz: size of data.
> + * @timestamp: timestamp for the sample data.
> + *
> + * This special variant of iio_push_to_buffers_with_timetamp() does
> + * not require space for the timestamp, or 8 byte alignment of data.
> + * It does however require an allocation on first call and additional
> + * coppies on all calls, so should be avoided if possible
copies
> + */
I do not like the _na part in the name (My first impression was with a
Timestamp that was not available, what?!). Can we spell it better?
> +int iio_push_to_buffers_with_ts_na(struct iio_dev *indio_dev,
> + const void *data,
> + size_t data_sz,
> + int64_t timestamp)
> +{
> + struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
> +
> + data_sz = min_t(size_t, indio_dev->scan_bytes, data_sz);
> + if (iio_dev_opaque->bounce_buffer_size != indio_dev->scan_bytes) {
> + iio_dev_opaque->bounce_buffer =
> + devm_krealloc(&indio_dev->dev,
> + iio_dev_opaque->bounce_buffer,
Oh la la, foo = realloc(foo, ...) is 101 type of mistakes.
Please, don't do this.
> + indio_dev->scan_bytes, GFP_KERNEL);
> + if (!iio_dev_opaque)
> + return -ENOMEM;
> + }
> + memcpy(iio_dev_opaque->bounce_buffer, data, data_sz);
> + return iio_push_to_buffers_with_timestamp(indio_dev,
> + iio_dev_opaque->bounce_buffer,
> + timestamp);
> +}
--
With Best Regards,
Andy Shevchenko
