On Fri, Dec 13, 2024 at 06:53:55PM +0000, Matthew Wilcox wrote:
> On Fri, Dec 13, 2024 at 07:51:50PM +0100, Christian Brauner wrote:
> > Yeah, it does. Did you see the patch that is included in the series?
> > I've replaced the macro with always inline functions that select the
> > lock based on the flag:
> >
> > static __always_inline void mtree_lock(struct maple_tree *mt)
> > {
> > if (mt->ma_flags & MT_FLAGS_LOCK_IRQ)
> > spin_lock_irq(&mt->ma_lock);
> > else
> > spin_lock(&mt->ma_lock);
> > }
> > static __always_inline void mtree_unlock(struct maple_tree *mt)
> > {
> > if (mt->ma_flags & MT_FLAGS_LOCK_IRQ)
> > spin_unlock_irq(&mt->ma_lock);
> > else
> > spin_unlock(&mt->ma_lock);
> > }
> >
> > Does that work for you?
>
> See the way the XArray works; we're trying to keep the two APIs as
> close as possible.
>
> The caller should use mtree_lock_irq() or mtree_lock_irqsave()
> as appropriate.
Say I need:
spin_lock_irqsave(&mt->ma_lock, flags);
mas_erase(...);
-> mas_nomem()
-> mtree_unlock() // uses spin_unlock();
// allocate
-> mtree_lock() // uses spin_lock();
spin_lock_irqrestore(&mt->ma_lock, flags);
So that doesn't work, right? IOW, the maple tree does internal drop and
retake locks and they need to match the locks of the outer context.
So, I think I need a way to communicate to mas_*() what type of lock to
take, no? Any idea how you would like me to do this in case I'm not
wrong?
