From: Davide Libenzi <davidel@xmailserver.org>
To: Benjamin LaHaise <bcrl@kvack.org>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Ingo Molnar <mingo@elte.hu>,
Suparna Bhattacharya <suparna@in.ibm.com>,
Zach Brown <zach.brown@oracle.com>
Subject: Re: [patch 13/13] signalfd/timerfd/asyncfd v5 - KAIO asyncfd support (example/maybe-broken) ...
Date: Wed, 14 Mar 2007 16:24:54 -0700 (PDT) [thread overview]
Message-ID: <Pine.LNX.4.64.0703141620340.4982@alien.or.mcafeemobile.com> (raw)
In-Reply-To: <20070314231920.GB1246@kvack.org>
On Wed, 14 Mar 2007, Benjamin LaHaise wrote:
> On Wed, Mar 14, 2007 at 03:19:21PM -0700, Davide Libenzi wrote:
> > + /*
> > + * Check if the user asked us to deliver the result through an
> > + * asyncfd. Note that asyncfd_add_results() may sleep. It seems
> > + * OK looking at the code, but I'm not sure since inside a USB driver,
> > + * aio_complete() is called with a spinlock held. !!CHECK
> > + */
>
> That won't work. aio_complete() is supposed to be irq safe.
Can you point me to a kernel path that ends up calling aio_complete() in a
do-not-sleep mode?
The offender I see is drivers/usb/gadget/inode.c that calls it with a
spinlock held.
The aio_run_iocb function seem to release/reacquire the lock before
calling aio_complete().
- Davide
next prev parent reply other threads:[~2007-03-14 23:29 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-03-14 22:19 Davide Libenzi
2007-03-14 23:19 ` Benjamin LaHaise
2007-03-14 23:24 ` Davide Libenzi [this message]
2007-03-14 23:42 ` Benjamin LaHaise
2007-03-14 23:41 ` Davide Libenzi
2007-03-14 23:49 ` Davide Libenzi
2007-03-15 0:02 ` Benjamin LaHaise
2007-03-15 0:10 ` Davide Libenzi
2007-03-15 0:27 ` Davide Libenzi
2007-03-15 0:15 ` Linus Torvalds
2007-03-15 0:15 ` Davide Libenzi
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