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| author | Alexandru Ardelean <aardelean@deviqon.com> | 2021-03-22 09:41:35 +0100 |
|---|---|---|
| committer | Jonathan Cameron <Jonathan.Cameron@huawei.com> | 2021-04-07 09:36:35 +0200 |
| commit | 4c822244bf4a0fc7f0f5120dc4dae4e9aa815ea6 (patch) | |
| tree | 058540e6ebebebae96c7f0fcdebebe8ca09816b2 /drivers/iio | |
| parent | iio: Fix iio_read_channel_processed_scale() (diff) | |
| download | linux-4c822244bf4a0fc7f0f5120dc4dae4e9aa815ea6.tar.xz linux-4c822244bf4a0fc7f0f5120dc4dae4e9aa815ea6.zip | |
iio: buffer: return 0 for buffer getfd ioctl handler
As Lars pointed out, we could either return the FD vs memcpy-ing it to the
userspace data object.
However, this comment exposed a bug. We should return 0 or negative from
these ioctl() handlers. Because an ioctl() handler can also return
IIO_IOCTL_UNHANDLED (which is positive 1), which means that the ioctl()
handler doesn't support this ioctl number. Positive 1 could also be a valid
FD number in some corner cases.
The reason we did this is to be able to differentiate between an error
code and an unsupported ioctl number; for unsupported ioctl numbers, the
main loop should keep going.
Maybe we should change this to a higher negative number, to avoid such
cases when/if we add more ioctl() handlers.
Cc: Lars-Peter Clausen <lars@metafoo.de>
Fixes: f73f7f4da5818 ("iio: buffer: add ioctl() to support opening extra buffers for IIO device")
Signed-off-by: Alexandru Ardelean <aardelean@deviqon.com>
Link: https://lore.kernel.org/r/20210322084135.17536-1-aardelean@deviqon.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Diffstat (limited to 'drivers/iio')
| -rw-r--r-- | drivers/iio/industrialio-buffer.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c index ccc8a8cae604..2ea52813e201 100644 --- a/drivers/iio/industrialio-buffer.c +++ b/drivers/iio/industrialio-buffer.c @@ -1442,7 +1442,7 @@ static long iio_device_buffer_getfd(struct iio_dev *indio_dev, unsigned long arg goto error_free_ib; } - return fd; + return 0; error_free_ib: kfree(ib); |