On Tue, Jul 18, 2023 at 03:42:00PM +0000, Charles Keepax wrote:
> On Thu, Jul 13, 2023 at 01:49:26AM +0100, Mark Brown wrote:
> > The maple tree register cache is based on a much more modern data structure
> > than the rbtree cache and makes optimisation choices which are probably
> > more appropriate for modern systems than those made by the rbtree cache. In
> > v6.5 it has also acquired the ability to generate multi-register writes in
> > sync operations, bringing performance up to parity with the rbtree cache
> > there.
> >
> > Update the wm5110 driver to use the more modern data structure.
> >
> > Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
> > ---
> > drivers/mfd/wm5110-tables.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/mfd/wm5110-tables.c b/drivers/mfd/wm5110-tables.c
> > index 65b9b1d6daec..eba324875afd 100644
> > --- a/drivers/mfd/wm5110-tables.c
> > +++ b/drivers/mfd/wm5110-tables.c
> > @@ -3218,7 +3218,7 @@ const struct regmap_config wm5110_i2c_regmap = {
> > .readable_reg = wm5110_readable_register,
> > .volatile_reg = wm5110_volatile_register,
> >
> > - .cache_type = REGCACHE_RBTREE,
> > + .cache_type = REGCACHE_MAPLE,
> > .reg_defaults = wm5110_reg_default,
> > .num_reg_defaults = ARRAY_SIZE(wm5110_reg_default),
> > };
> >
> > --
> > 2.39.2
> >
>
> This one appears to cause me some issues, seems to get the IRQs
> into a weird state when doing compressed stream stuff. The
> issue seems to also require commit bfa0b38c1483 ("regmap:
> maple: Implement block sync for the maple tree cache") to be
> present. So it definitely seems to relate to the cache sync,
> but not sure if it is something todo with the device itself,
> or the maple tree stuff yet.
>
Ah... I think I see the regcache_sync sets async=true, but then
the maple tree code immediately deletes the buffer after calling
_regmap_raw_write. So its a racy use after free.
How would we feel about having the maple tree code, clear async
again?
Thanks,
Charles
