linux-kernel - Re: [PATCH 1/2] brw_mutex: big read-write mutex

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]

Date:	Fri, 26 Oct 2012 14:06:05 +0200
From:	Oleg Nesterov <oleg@...hat.com>
To:	Dave Chinner <david@...morbit.com>
Cc:	Mikulas Patocka <mpatocka@...hat.com>,
	Peter Zijlstra <peterz@...radead.org>,
	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Ingo Molnar <mingo@...e.hu>,
	Srikar Dronamraju <srikar@...ux.vnet.ibm.com>,
	Ananth N Mavinakayanahalli <ananth@...ibm.com>,
	Anton Arapov <anton@...hat.com>, linux-kernel@...r.kernel.org,
	Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [PATCH 1/2] brw_mutex: big read-write mutex

On 10/26, Dave Chinner wrote:
>
> On Thu, Oct 25, 2012 at 10:09:31AM -0400, Mikulas Patocka wrote:
> >
> > Yes, mnt_want_write()/mnt_make_readonly() do the same thing as percpu rw
> > semaphores. I think you can convert mnt_want_write()/mnt_make_readonly()
> > to use percpu rw semaphores and remove the duplicated code.
>
> I think you misunderstood my point - that rather than re-inventing
> the wheel, why didn't you just copy something that is known to
> work?

I don't understand why do you both think that __mnt_want_write()
and mnt_make_readonly() provides the same functionality. I looked
at this code before I started this patch, and unless I completely
misread it this does very different things. It is not "lock" at all.

Oleg.

--
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/