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From: Oliver Neukum <oliver@neukum.org>
To: Matthew Dharm <mdharm-kernel@one-eyed-alien.net>,
	David Brownell <david-b@pacbell.net>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>,
	Marcelo Tosatti <marcelo.tosatti@cyclades.com.br>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	USB Developers <linux-usb-devel@lists.sourceforge.net>,
	Greg KH <greg@kroah.com>
Subject: Re: [linux-usb-devel] Re: USB hangs
Date: Mon, 12 Jan 2004 09:37:19 +0100	[thread overview]
Message-ID: <200401120937.19131.oliver@neukum.org> (raw)
In-Reply-To: <20040112073905.GA8580@one-eyed-alien.net>

Am Montag, 12. Januar 2004 08:39 schrieb Matthew Dharm:
> On Sun, Jan 11, 2004 at 08:11:58PM -0800, David Brownell wrote:
> > 
> > >>>	 Plus I'd
> > >>>argue PF_MEMALLOC is a better solution anyway.
> > >>
> > >>It certainly seems like a more comprehensive fix for that
> > >>particular class of problems!  :)
> > >
> > >
> > >Is it really more comprehensive?  As I see it, it will only affect code
> > >executed in the context of the usb-storage thread.  But, what about code
> > >which is invoked in tasklets or other contexts?
> > 
> > Isn't it true that only that thread is allowed to
> > submit usb-storage i/o requests?
> 
> That's very true.
> 
> What I'm concerned about is the downstream effects of a usb_submit_urb() or
> the corresponding scatter-gather equivalents.

In 2.4 they all run in interrupt or thread context IIRC.
Problematic is the SCSI error handling thread. It can call usb_reset_device()
which calls down and does allocations.
Does that thread also do the PF_MEMALLOC trick?

	Regards
		Oliver



  reply	other threads:[~2004-01-12  8:37 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-01-11  0:07 USB hangs Alan Cox
2004-01-11  0:23 ` Matthew Dharm
2004-01-11  0:49   ` [linux-usb-devel] " Oliver Neukum
2004-01-11  1:01     ` Matthew Dharm
2004-01-11  1:06       ` Oliver Neukum
2004-01-11  1:40     ` David Brownell
2004-01-11  2:33   ` Alan Cox
2004-01-11  8:02     ` [linux-usb-devel] " Oliver Neukum
2004-01-11 22:39       ` Alan Cox
2004-01-11 23:29         ` Oliver Neukum
2004-01-12 15:53           ` Alan Stern
2004-01-11 23:25     ` David Brownell
2004-01-11 23:31       ` Matthew Dharm
2004-01-12  4:11         ` David Brownell
2004-01-12  7:39           ` Matthew Dharm
2004-01-12  8:37             ` Oliver Neukum [this message]
2004-01-12 16:27               ` Alan Stern
2004-01-12 20:56                 ` Alan Cox
2004-01-16 13:14                 ` Pavel Machek
2004-01-11 23:33       ` Oliver Neukum
2004-01-12  0:09         ` Alan Cox
2004-01-12  0:25           ` Matthew Dharm
2004-01-11 18:46 ` Lukas Postupa
2004-01-11 20:04   ` Matthew Dharm
  -- strict thread matches above, loose matches on Subject: below --
2004-01-28 16:50 [linux-usb-devel] " Martin Bogomolni

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