Date: Thu, 15 Mar 2007 14:14:00 +0300 From: Yar Tikhiy <yar@comp.chem.msu.su> To: "Bruce M. Simpson" <bms@FreeBSD.org> Cc: freebsd-net@FreeBSD.org, freebsd-arch@FreeBSD.org Subject: Re: Generic ioctl and ether_ioctl don't agree Message-ID: <20070315111400.GC28354@comp.chem.msu.su> In-Reply-To: <45F7EF84.5070700@FreeBSD.org> References: <20070314102023.GB1766@comp.chem.msu.su> <45F7EF84.5070700@FreeBSD.org>
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On Wed, Mar 14, 2007 at 12:50:12PM +0000, Bruce M. Simpson wrote: > Yar Tikhiy wrote: > >Hi folks, > > > >Quite a while ago I noticed that our ioctl handlers get the ioctl > >command via u_long, but ether_ioctl()'s command argument is int. > >This disarray dates back to 1998, when ioctl functions started to > >take u_long as the command, but ether_ioctl() was never fixed. > >Fortunately, our ioctl command coding still fits in 32 bits, or > >else we would've got problems on 64-bit arch'es already. I'd like > >to fix this long-standing bug some day after RELENG_7 is branched. > >Of course, this will break ABI to network modules on all 64-bit > >arch'es. BTW, the same applies to other L2 layers, such as firewire, > >which seems to have been cloned from if_ethersubr.c. > > > This is one of those annoying things which breaks compatibility with > external modules. > > I'm not sure about this, though. I was getting sign extension warnings > on amd64 last week when I was testing the IGMPv3 aware mtest(8). Perhaps > if we're fixing these ABIs, we should commit to an explicit C99 type > with known bit width, i.e. uint32_t. > > I would be much happier if we began using C99 types in the code. This is a point to discuss in -arch as it's closely related to the generic ioctl interface. Let's move this thread to -arch. It's been a vague issue to me whether to use a fixed-width type or a basic type in particular kernel code. Of course, it's better to use a fixed-width type when it comes to network packets or hardware registers. OTOH, errno is int. But not all cases are that simple. Do we have a guideline for that? -- Yar
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