From: Soren Hansen <soren@linux2go.dk>
To: "Serge E. Hallyn" <serge@hallyn.com>
Cc: linux-kernel@vger.kernel.org, Dave Hansen <haveblue@us.ibm.com>
Subject: Re: nbd locking problems
Date: Sat, 29 Jan 2011 00:11:53 +0100 [thread overview]
Message-ID: <AANLkTi=1ubso_qg1dr+xOaF4s=f0Jfzchinh3dnY7jjY@mail.gmail.com> (raw)
In-Reply-To: <20110128211825.GA20707@mail.hallyn.com>
2011/1/28 Serge E. Hallyn <serge@hallyn.com>:
> Thanks for looking into this, Soren.
Sure :)
> As Dave just explained to me, BKL is released when you sleep :)
Ah, yes, that makes perfect sense.
> I assume that's how it gets released around the kthread_create(). I
> *think* you're right that the new mutex is superfluous, but I'd like to
> look through the ioctl code and make sure there's no shared state which
> we need to protect.
Yup, I've tried that and I didn't find anything, but this is very new
territory to me, so more eyes sounds great.
> I don't see how there could be, or rather, if there
> were, then it was broken before.
Good point.
> In the meantime, could you please post your patch? (Is it the
> three-liner I'd expect?)
Indeed it is. I was holding off on posting it, because I was hoping
Pavel Machek would chime in. Pavel's commit message in [1] suggested
that there was more work to do before the BKL could be vanquished from
this driver (by changing .ioctl to .unlocked_ioctl).
I guess it can't hurt to post it, though. I'll do that in a second.
[1]: 1a2ad21128bb4eb79f3c05e5801edcc5ed3ef1d3
--
Soren Hansen | http://linux2go.dk/
Ubuntu Developer | http://www.ubuntu.com/
OpenStack Developer | http://www.openstack.org/
next prev parent reply other threads:[~2011-01-28 23:11 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-01-26 10:52 nbd locking problems Soren Hansen
2011-01-28 21:18 ` Serge E. Hallyn
2011-01-28 21:30 ` Arnd Bergmann
2011-01-28 23:11 ` Soren Hansen [this message]
2011-03-13 10:28 ` Pavel Machek
2011-01-31 19:35 ` Serge E. Hallyn
2011-01-28 23:23 ` [PATCH] nbd: Remove module-level ioctl mutex Soren Hansen
2011-01-30 15:07 nbd locking problems Paul Clements
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