From: Nuno Sá <nuno.sa@xxxxxxxxxx> commit b5184a26a28fac1d708b0bfeeb958a9260c2924c upstream. If for some reason 'rb->access->write()' does not write the full requested data and the O_NONBLOCK is set, we would return 'n' to userspace which is not really truth. Hence, let's return the number of bytes we effectively wrote. Fixes: 9eeee3b0bf190 ("iio: Add output buffer support") Signed-off-by: Nuno Sá <nuno.sa@xxxxxxxxxx> Reviewed-by: Lars-Peter Clausen <lars@xxxxxxxxxx> Link: https://lore.kernel.org/r/20230216101452.591805-2-nuno.sa@xxxxxxxxxx Cc: <Stable@xxxxxxxxxxxxxxx> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/iio/industrialio-buffer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/iio/industrialio-buffer.c +++ b/drivers/iio/industrialio-buffer.c @@ -220,7 +220,7 @@ static ssize_t iio_buffer_write(struct f } while (ret == 0); remove_wait_queue(&rb->pollq, &wait); - return ret < 0 ? ret : n; + return ret < 0 ? ret : written; } /**