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From: Stefan Richter <stefanr@s5r6.in-berlin.de>
To: "Greg Kroah-Hartman" <gregkh@suse.de>,
	"Kristian Høgsberg" <krh@bitplanet.net>
Cc: linux1394-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] firewire: reread config ROM when device reset the bus
Date: Mon, 03 Mar 2008 19:35:07 +0100	[thread overview]
Message-ID: <47CC44DB.1060203@s5r6.in-berlin.de> (raw)
In-Reply-To: <47CC3C48.1020306@s5r6.in-berlin.de>

I wrote:
>> On Mon, Mar 3, 2008 at 11:51 AM, Stefan Richter
>> <stefanr@s5r6.in-berlin.de> wrote:
[...rewriting data of a device with children devices whose driver probe 
accesses these data...]
>>>  Maybe I should rather use fw-device.c::idr_rwsem instead of device.sem,
>>>  to have better control over who takes the mutex when.  Could also be a
>>>  new dedicated mutex but we don't want to end up with too many of 
>>>  them...
[...]
> Ah, wait, there is a 3rd reader: sbp2_probe's sbp2_scan_unit_dir.  So, 
> using dev->sem is actually the nicest way for now.

Or not.  The necessary protection for this and other driver->probe()s 
would be the device->parent.sem, not the device->sem itself.  There seem 
to be several ways how a driver probe may be entered (adding a device 
when the driver is already there; attaching a driver when the device is 
already there...) and I am not sure whether all these paths take the 
device->parent.sem around the probe.  It doesn't seem to be always the case.

Greg, can you comment on this?
-- 
Stefan Richter
-=====-==--- --== ---==
http://arcgraph.de/sr/

  reply	other threads:[~2008-03-03 18:35 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-03-02 18:35 [PATCH] firewire: replace static ROM cache by allocated cache Stefan Richter
2008-03-03  0:48 ` [PATCH] firewire: reread config ROM when device reset the bus Stefan Richter
2008-03-03 16:17   ` Kristian Høgsberg
2008-03-03 16:51     ` Stefan Richter
2008-03-03 17:28       ` Kristian Høgsberg
2008-03-03 17:58         ` Stefan Richter
2008-03-03 18:35           ` Stefan Richter [this message]
2008-03-04  5:54             ` Greg KH
2008-03-04  8:39               ` Stefan Richter
2008-03-05  0:34     ` [PATCH update] " Stefan Richter
2008-03-05  0:48       ` Stefan Richter
2008-03-05 23:53         ` Stefan Richter
2008-03-06  1:25           ` Stefan Richter
2008-03-03 20:28   ` [PATCH] " Jarod Wilson

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