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author | Alexandru Ardelean <aardelean@deviqon.com> | 2021-03-22 10:41:35 +0200 |
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committer | Jonathan Cameron <Jonathan.Cameron@huawei.com> | 2021-04-07 08:36:35 +0100 |
commit | 4c822244bf4a0fc7f0f5120dc4dae4e9aa815ea6 (patch) | |
tree | 058540e6ebebebae96c7f0fcdebebe8ca09816b2 /drivers/iio/imu | |
parent | iio: Fix iio_read_channel_processed_scale() (diff) | |
download | linux-dev-4c822244bf4a0fc7f0f5120dc4dae4e9aa815ea6.tar.xz linux-dev-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/imu')
0 files changed, 0 insertions, 0 deletions