From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vojtech Pavlik Date: Fri, 09 Feb 2001 15:45:34 +0000 Subject: Re: Adding PCMCIA support to the kernel tree -- developers needed. Message-Id: List-Id: References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-hotplug@vger.kernel.org On Fri, Feb 09, 2001 at 02:09:39PM +0100, Oliver Neukum wrote: > > > You can retry, you are right. I failed to see that. > > > But you seem to suffer from the name reuse race. > > > > > > reality task A task B > > > plug in dev A > > > bind dev A to name 0 > > > unplug dev A > > > unbind name 0 > > > plug in dev B > > > bind dev B to name 0 > > > do something arbitrary > > > to the dev associated > > > with name 0 > > > > > > If the kernel would select name 0, it could lock on name 0. > > > With your scheme this is hard to do. > > > > Unbind on name 0 should block until task A finishes the arbitrary stuff. > > Is there any problem with that? We could even have a 'setup finished' > > ioctl for this, though I think I'd prefer just having one task per action. > > This would work provided that the lock is taken atomically with binding to > the name. Yep, that's what I intended. > > > Nor do you absolutely need to. > > > You can already rename network devices by ioctl. > > > For everything else a humble symlink should do the job, shouldn't it ? > > > > Yes, but with humble symlinks you will run out of minor/major numbers soon. > > Why is that ? Even if you assign numbers by the agent you would take them out > of a pool of numbers the kernel could also use. > In both cases it would seem that devices use the same amount of numbers. Actually, you're right. For some reason I was assuming the symlinks would have to point to stable names - unique at least for each topology path. This is not completely necessary, though. > > > Else you introduce complexity without much gain. > > > And you need renaming in any case, as device names may have been assigned > > > during boot. > > > > Yes. Symlinks would help here, however, you'd probably need devfs in > > that case. > > I can see devfs helping tremendously with providing stable names, but why is > it necessary ? It isn't needed - I was assuming the symlinks would have to point to stable names. -- Vojtech Pavlik SuSE Labs _______________________________________________ Linux-hotplug-devel mailing list http://linux-hotplug.sourceforge.net Linux-hotplug-devel@lists.sourceforge.net http://lists.sourceforge.net/lists/listinfo/linux-hotplug-devel