Hi Laura, On Fri, May 18, 2018 at 12:32 AM, Laura Abbott <[email protected]> wrote: > The new challenge is to remove VLAs from the kernel > (see https://lkml.org/lkml/2018/3/7/621) to eventually > turn on -Wvla. > > Using a kmalloc array is the easy way to fix this but kmalloc is still > more expensive than stack allocation. Introduce a fast path with a > fixed size stack array to cover most chip with gpios below some fixed > amount. The slow path dynamically allocates an array to cover those > chips with a large number of gpios. > > Reviewed-by: Phil Reid <[email protected]> > Reviewed-and-tested-by: Lukas Wunner <[email protected]> > Signed-off-by: Lukas Wunner <[email protected]> > Signed-off-by: Laura Abbott <[email protected]> > --- > v7: Tweaked the Kconfig text to clarify the wording. Also fixed a few > other comments from Geert, including the earlier suggestion to reduce > the zeroing since I was wrong about that.
Thanks for the update! With the minor nit below resolved: Reviewed-by: Geert Uytterhoeven <[email protected]> > --- a/drivers/gpio/Kconfig > +++ b/drivers/gpio/Kconfig > @@ -22,6 +22,18 @@ menuconfig GPIOLIB > > if GPIOLIB > > +config GPIOLIB_FASTPATH_LIMIT > + int "Maximum number of GPIOs for fast path" > + range 16 512 While you can indeed fit 2 * 16 bits in a long, a lower limit of 16 doesn't make much sense, as you will use 2 longs (mask + bits) anyway. So please increase it to 32. Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- [email protected] In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
