linux-kernel - Re: Burning multiple DVDs at one time

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20120428160226.GA9811@animx.eu.org>
Date:	Sat, 28 Apr 2012 12:02:27 -0400
From:	Wakko Warner <wakko@...mx.eu.org>
To:	Stefan Richter <stefanr@...6.in-berlin.de>
Cc:	linux-kernel@...r.kernel.org, linux-scsi@...r.kernel.org
Subject: Re: Burning multiple DVDs at one time

Stefan Richter wrote:
> On Mar 18 Wakko Warner wrote:
> > Stefan Richter wrote:
> > > On Mar 17 Wakko Warner wrote:
> > > > Thanks.  I looked at the patch.  I would just like to confirm that I can
> > > > patch my 3.0.0 vanilla kernel, compile the sr module, unload the current and
> > > > load the patched one without the need to reboot.
> > > 
> > > Yes, this should be possible.
> > > 
> > > Oh, I only noticed just know that you also wrote:
> > > 
> > > > > > The kernel is a vanilla kernel v3.0.0.  (This also happened with 2.6.35)
> > > 
> > > In 2.6.35, the Big Kernel Lock was still in place there.  That lock
> > > behaved differently from a plain mutex --- notably it was released when a
> > > thread went to sleep --- so maybe there is more to your problem than just
> > > sr_mutex blocking unrelated sr accesses.
> > 
> > There is a good possibility that I was mistaken on the 2.6.35.
> > 
> > I manually applied your patch to 3.0.0, compiled, removed sr-mod module and
> > inserted the newly compiled one.
> > 
> > With the vanilla one, I would see the buf % in wodim drop while the fifo was
> > full.  With the patch (removing the mutex), buf stayed above 98% and the
> > burn speed was 16x at the end (10x avg).
> > 
> > Seems to have fixed my problem.
> 
> Very nice; so there is an almost easy fix.  Now I or somebody else need to
> work out the required cdrom_device_info protection on which Arnd and James
> commented.

Has anything come of this as far as the fix going into the kernel?

-- 
 Microsoft has beaten Volkswagen's world record.  Volkswagen only created 22
 million bugs.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/