Searched hist:"4 c822244bf4a0fc7f0f5120dc4dae4e9aa815ea6" (Results 1 – 1 of 1) sorted by relevance
| /openbmc/linux/drivers/iio/ |
| H A D | industrialio-buffer.c | diff 4c822244bf4a0fc7f0f5120dc4dae4e9aa815ea6 Mon Mar 22 03:41:35 CDT 2021 Alexandru Ardelean <aardelean@deviqon.com> 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>
|