iio: core: return -EINVAL when no ioctl handler has been run

It seems that when this was tested the happy case was more tested. A few of
the userspace apps rely on this returning negative error codes in case an
ioctl() is not available.

When running multiple ioctl() handlers or when calling an ioctl() that
doesn't exist, IIO_IOCTL_UNHANDLED is returned. In that case -EINVAL should
be returned.

Fixes: 8dedcc3eee3a ("iio: core: centralize ioctl() calls to the main chardev")
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20201117095154.7189-1-alexandru.ardelean@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
index 89f9af12c8e64c93b48f6f15d38e31c24472daa5..7cae46f9bc0d7ef0aa165923880339050dd6b4be 100644 (file)
--- a/drivers/iio/industrialio-core.c
+++ b/drivers/iio/industrialio-core.c
@@ -1743,6 +1743,9 @@ static long iio_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
                        break;
        }
 
+       if (ret == IIO_IOCTL_UNHANDLED)
+               ret = -EINVAL;
+
 out_unlock:
        mutex_unlock(&indio_dev->info_exist_lock);