Date: Tue, 27 Mar 2001 08:04:01 +0200 From: Poul-Henning Kamp <phk@critter.freebsd.dk> To: Greg Lehey <grog@lemis.com> Cc: Mike Smith <msmith@freebsd.org>, John Baldwin <jhb@freebsd.org>, leclercn@videotron.ca, freebsd-alpha@freebsd.org Subject: Re: dev_t size mismatch kernel / userland Message-ID: <73387.985673041@critter> In-Reply-To: Your message of "Tue, 27 Mar 2001 09:33:27 %2B0930." <20010327093327.A40349@wantadilla.lemis.com>
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In message <20010327093327.A40349@wantadilla.lemis.com>, Greg Lehey writes: >On Monday, 26 March 2001 at 13:00:32 -0800, Mike Smith wrote: >>>> This will probably make Poul's head spin, but one idea might be to have a >>>> kdev_t type. :-P In the kernel kdev_t == dev_t, and in userland, kdev_t is a >>>> void *. This would work in this case I think because you never use the dev_t's >>>> while in userland. I do like exporting trimmed down structures, however. >>>> Please don't export mutexes while you are at it. :-P >>> >>> Guys, >>> >>> I'm new to this subject, so please fill me in: just what in the >>> (kernel) dev_t do you want to export to userland ? >> >> Nothing. Greg just leaks a dev_t in a structure exchanged between >> userland and the kernel, and this bit because dev_t is a different >> size between the two on the Alpha; the right fix is simply to not >> abuse this structure like this. > >You're missing a number of things here. If a dev_t is defined in >userland, it should be the same size as in the kernel. The current >situation is obviously a bug. The current situation is the best compromise between breaking POSIX compliance for userland or source-code compatibility for the kernel. >It's certainly open to discussion >whether the dev_t definition in userland gets removed or fixed. The userland definition of dev_t is not changeable without breaking POSIX compliance. If you ratify on arch@ that "dev_t" gets renamed in the kernel, then I'll do the work. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-alpha" in the body of the message
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