RE: [PATCH v3] net: bluetooth: hci_sock: Use 'const u32 *' instead of 'void *' for 2nd parameter of hci_test_bit()

From: David Laight
Date: Mon Feb 09 2015 - 11:59:09 EST


From: Marcel Holtmann
> Hi David,
>
> >> So at present, in kernel part, we can only say the original authors
> >> intended to do like this. And only within kernel part, it can not cause
> >> issue. I guess, original authors originally knew what we talk about.
> >
> > I've just searched for hci_u*filter it is all horrid.
> > Look at the code for get/set_sockopt of HCI_FILTER.
> > Someone seems to have done a complete 'bodge job' of fixing the user interface
> > for apps (32bit and 64bit) on 64bit kernels.
>
> we are actually fully aware of that. Just keep in mind that this code is from 2.4.6 kernel and with
> that most likely 14 years old by now. Unfortunately it ended up as userspace API.

AFAICT the userspace API is always __u32[2] the long[2] is never exposed
to userspace (certainly not through the socket option code).

Quite why all the casts were added - instead of changing the type
is probably hidden in the annals of the source repo.
Some serious archaeology might be in order.

David

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