On Sat, Apr 21, 2001 at 03:17:37PM +0100, Russell King wrote:
> On Sat, Apr 21, 2001 at 04:03:27PM +0200, Andrea Arcangeli wrote:
> > On Fri, Apr 20, 2001 at 04:45:32PM -0700, Linus Torvalds wrote:
> > > I would suggest the following:
> > >
> > > - the generic semaphores should use the lock that already exists in the
> > > wait-queue as the semaphore spinlock.
> >
> > Ok, that is what my generic code does.
>
> Erm, spin_lock()? What if up_read or up_write gets called from interrupt
> context (is this allowed)?
That it is allowed by my generic code that does spin_lock_irq in down_* and
spin_lock_irqsave in up_* but it's disallowed by the weaker semantics of the
generic and x86 semaphores 2.4.4pre[2345] (or + David's last patch).
> If these are now allowed, then maybe we should either consider getting
> the Stanford checker to check for this, or else we ought to do a debugging
> if (in_interupt()) BUG(); thing.
Caller bug is the last of my worries. (and I seriously doubt that if somebody
doesn't know the semantics of the rwsem, he will care to enable the debugging
checks during regression testing ;)
Andrea
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This archive was generated by hypermail 2b29 : Mon Apr 23 2001 - 21:00:39 EST