svn commit: r192535 - head/sys/kern

[Attilio Rao]

2009/5/21 Attilio Rao <attilio at freebsd.org>:
> 2009/5/21 Kostik Belousov <kostikbel at gmail.com>:
>> On Thu, May 21, 2009 at 01:22:07PM +0000, Attilio Rao wrote:
>>> Author: attilio
>>> Date: Thu May 21 13:22:07 2009
>>> New Revision: 192535
>>> URL: http://svn.freebsd.org/changeset/base/192535
>>>
>>> Log:
>>>   Move the M_WAITOK flag in notify() into an M_NOWAIT one in order to match
>>>   the behaviour alredy present with the further malloc() call in
>>>   devctl_notify().
>>>   This fixes a bug in the CAM layer where the camisr handler finished to
>>>   call camperiphfree() (and subsequently destroy_dev() resulting in a new
>>>   dev notify) while the xpt lock is held.
>> This is wrong. You cannot call destroy_dev() while holding any mutex.
>> Taking this into account, it makes no sense to use M_NOWAIT in notify().
>
> As long as devctl_notify() also calls M_NOWAIT and if not available
> skips "silently" it just does the same thing, I think this approach is
> more consistent.
>
> It remains, though, the fact to fix CAM when calling destroy_dev().
> Maybe we should add a witness_warn() there?

s/add/also add

Attilio


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