Re: [PATCH] char/mem: Make /dev/port less obviously broken (v0)

From: Adam Jackson
Date: Mon Feb 06 2012 - 22:57:25 EST

On 2/6/12 7:15 PM, Greg KH wrote:

Who would use this new ioctl? And if it's been working ok until now,
why is it needed?

I'll go out on a limb and say nobody's been seriously using /dev/port. libpciaccess would like to, since it avoids needing iopl, and also avoids duplicating all the kernel's per-arch logic for port access in userspace. But if it's not going to give me the cycle size I asked for I need to fix it before I can use it. Otherwise you get what I'm getting, which is a vesa driver that doesn't work.

Adding the ioctl was just me being polite and assuming that user-kernel ABI was a thing we actually believe in. If it's not, great, let's just fix /dev/port to not be idiotic. If it is, I'd prefer not wasting the memory on another inode.

If you want something "new" like this, why not just create /dev/ioport
or something like that to always use the proper alignment and not need
an ioctl at all?

If you really want that shed painted a different color, fine.

- ajax
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