Re: [PATCH][RFC] 2.6.6 tty_io.c hangup locking

[Andrew Morton]

Paul Fulghum <paulkf@xxxxxxxxxxxxx> wrote:
>
> The following patch removes unnecessary disabling of
> interrupts when processing hangup for tty devices.

Ho hum, this has been hanging around forever.  Obviously the current
locking is pointless and the only useful locking we have in there is
lock_kernel().

The reason why a patch such as yours wasn't applied is that it was all kept
as a reminder that we suck.  Someone needs to get down and audit what's
actually happening in there.  It seems that you've now done that via
comparison with other callers, but that is not necessarily a good approach
when it comes to the tty layer ;)

We need to itemise all the affected memory storage in all impementations of
->flush_buffer() and ->write_wakeup() and then make sure that all _other_
users of those fields (whether or not they lie in the ->flush_buffer() and
->write_wakeup() codepaths) are using the same locking.  Is that something
you could do?
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