From: "Michael S. Tsirkin" <mst@redhat.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-m32r-ja@ml.linux-m32r.org, kvm@vger.kernel.org,
Peter Zijlstra <peterz@infradead.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
David Howells <dhowells@redhat.com>,
linux-mm@kvack.org, Paul Mackerras <paulus@samba.org>,
"H. Peter Anvin" <hpa@zytor.com>,
linux-arch@vger.kernel.org, linux-am33-list@redhat.com,
Hirokazu Takata <takata@linux-m32r.org>,
x86@kernel.org, Ingo Molnar <mingo@redhat.com>,
Arnd Bergmann <arnd@arndb.de>,
microblaze-uclinux@itee.uq.edu.au,
Chris Metcalf <cmetcalf@tilera.com>,
Thomas Gleixner <tglx@linutronix.de>,
linux-arm-kernel@lists.infradead.org,
Michal Simek <monstr@monstr.eu>,
linux-m32r@ml.linux-m32r.org, linux-kernel@vger.kernel.org,
Koichi Yasutake <yasutake.koichi@jp.panasonic.com>,
linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v2 10/10] kernel: might_fault does not imply might_sleep
Date: Sun, 19 May 2013 16:34:18 +0300 [thread overview]
Message-ID: <20130519133418.GA24381@redhat.com> (raw)
In-Reply-To: <1368966844.6828.111.camel@gandalf.local.home>
On Sun, May 19, 2013 at 08:34:04AM -0400, Steven Rostedt wrote:
> On Sun, 2013-05-19 at 12:35 +0300, Michael S. Tsirkin wrote:
>
> > No, I was not assuming that. What I'm trying to say is that a caller
> > that does something like this under a spinlock:
> > preempt_disable
> > pagefault_disable
> > error = copy_to_user
> > pagefault_enable
> > preempt_enable_no_resched
> >
> > is not doing anything wrong and should not get a warning,
> > as long as error is handled correctly later.
> > Right?
> >
>
> What I see wrong with the above is the preempt_enable_no_resched(). The
> only place that should be ever used is right before a schedule(), as you
> don't want to schedule twice (once for the preempt_enable() and then
> again for the schedule itself).
>
> Remember, in -rt, a spin lock does not disable preemption.
>
> -- Steve
Right but we need to keep it working on upstream as well.
If I do preempt_enable under a spinlock upstream won't it
try to sleep under spinlock?
--
MST
next prev parent reply other threads:[~2013-05-19 13:35 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-16 11:07 [PATCH v2 00/10] uaccess: better might_sleep/might_fault behavior Michael S. Tsirkin
2013-05-16 11:10 ` [PATCH v2 01/10] asm-generic: uaccess s/might_sleep/might_fault/ Michael S. Tsirkin
2013-05-16 11:10 ` [PATCH v2 02/10] arm64: " Michael S. Tsirkin
2013-05-16 13:29 ` Catalin Marinas
2013-05-16 11:10 ` [PATCH v2 03/10] frv: " Michael S. Tsirkin
2013-05-16 11:11 ` [PATCH v2 04/10] m32r: " Michael S. Tsirkin
2013-05-16 11:11 ` [PATCH v2 05/10] microblaze: " Michael S. Tsirkin
2013-05-16 11:12 ` [PATCH v2 06/10] mn10300: " Michael S. Tsirkin
2013-05-16 11:15 ` [PATCH v2 07/10] powerpc: " Michael S. Tsirkin
2013-05-22 13:59 ` Arnd Bergmann
2013-05-22 14:30 ` Michael S. Tsirkin
2013-05-24 13:00 ` Michael S. Tsirkin
2013-05-24 13:11 ` Michael S. Tsirkin
2013-05-24 13:30 ` Arnd Bergmann
2013-05-16 11:15 ` [PATCH v2 08/10] tile: " Michael S. Tsirkin
2013-05-16 13:33 ` Chris Metcalf
2013-05-16 11:15 ` [PATCH v2 09/10] x86: " Michael S. Tsirkin
2013-05-16 11:16 ` [PATCH v2 10/10] kernel: might_fault does not imply might_sleep Michael S. Tsirkin
2013-05-16 18:40 ` Peter Zijlstra
2013-05-19 9:35 ` Michael S. Tsirkin
2013-05-19 12:34 ` Steven Rostedt
2013-05-19 13:34 ` Michael S. Tsirkin [this message]
2013-05-19 16:06 ` Steven Rostedt
2013-05-19 16:40 ` Michael S. Tsirkin
2013-05-19 20:23 ` Steven Rostedt
2013-05-19 20:35 ` Michael S. Tsirkin
2013-05-21 11:18 ` Peter Zijlstra
2013-05-21 11:21 ` Peter Zijlstra
2013-05-21 11:57 ` Peter Zijlstra
2013-05-22 9:47 ` Michael S. Tsirkin
2013-05-22 10:16 ` Peter Zijlstra
2013-05-22 20:38 ` Michael S. Tsirkin
2013-05-22 20:36 ` Michael S. Tsirkin
2013-05-22 9:25 ` [PATCH v2 00/10] uaccess: better might_sleep/might_fault behavior Arnd Bergmann
2013-05-22 9:58 ` Michael S. Tsirkin
2013-05-22 10:19 ` Peter Zijlstra
2013-05-22 11:07 ` Michael S. Tsirkin
2013-05-22 11:27 ` Peter Zijlstra
2013-05-22 13:41 ` Russell King - ARM Linux
2013-05-22 14:04 ` Arnd Bergmann
2013-05-22 14:44 ` Michael S. Tsirkin
2013-05-24 14:18 ` [PATCH v3 07/11] powerpc: uaccess s/might_sleep/might_fault/ Michael S. Tsirkin
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