On Wed, 19 Oct 2005 11:48:57 -0700, Greg KH <[EMAIL PROTECTED]> wrote:

> > Also, do you see that rwlock which IS TAKEN FOR WRITE ONLY?
> > Why? The only explanation is: the author intended read locks
> > in notifier_call_chain, but either forgot them, or they were
> > dropped by other person.

> Ick, you are right.  I'll go redo my notifier code to get this right.

Greg, here's some info just in case it saves you some effort if you
decide to work inside the notifier. I did some research and composed
a message to you, but it disappeared somehow, and then I went away
for two days... Apparently, someone replaced spinlocks with rwlocks
and the lock was taken on read when traversing (around 2.4.0-pre1
or so). Then, it turned out that ANK's networking wants to delete
notifiers from a running notifier. So, someone else (Linus?) removed
the taking the lock for read. Now we have an rwlock which is only
taken for write :-)  Maybe it makes sense to look at 2.3.99.
It's all so shrouded in the mysts of time, that maybe it's easier
to lock outside now.

-- Pete


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