Re: [PATCH net-next v3 0/4] remove compat_alloc_user_space()

From: Arnd Bergmann
Date: Fri Nov 06 2020 - 16:48:39 EST


On Fri, Nov 6, 2020 at 6:32 PM Arnd Bergmann <arnd@xxxxxxxxxx> wrote:
>
> From: Arnd Bergmann <arnd@xxxxxxxx>
>
> This is the third version of my seires, now spanning four patches
> instead of two, with a new approach for handling struct ifreq
> compatibility after I realized that my earlier approach introduces
> additional problems.
>
> The idea here is to always push down the compat conversion
> deeper into the call stack: rather than pretending to be
> native mode with a modified copy of the original data on
> the user space stack, have the code that actually works on
> the data understand the difference between native and compat
> versions.
>
> I have spent a long time looking at all drivers that implement
> an ndo_do_ioctl callback to verify that my assumptions are
> correct. This has led to a series of 29 additional patches
> that I am not including here but will post separately, fixing
> a number of bugs in SIOCDEVPRIVATE ioctls, removing dead
> code, and splitting ndo_do_ioctl into two new ndo callbacks
> for private and ethernet specific commands.

I got a reply from the build bots that the version I sent was broken
on 32-bit machines, so don't merge it just yet. Let me know if
there are any other comments I should address before resending
though.

Arnd