Messages in this thread | | | From | Geert Uytterhoeven <> | Date | Tue, 24 Jan 2023 17:14:39 +0100 | Subject | Re: [PATCH] PM: runtime: Simplify __rpm_get_callback() |
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Hi Bjorn,
On Tue, Jan 24, 2023 at 4:06 PM Bjorn Helgaas <helgaas@kernel.org> wrote: > On Tue, Jan 24, 2023 at 03:45:50PM +0100, Rafael J. Wysocki wrote: > > On Tue, Jan 24, 2023 at 3:37 PM Geert Uytterhoeven <geert@linux-m68k.org> wrote: > > > On Tue, Jan 24, 2023 at 3:18 PM Rafael J. Wysocki <rafael@kernel.org> wrote: > > > > On Tue, Jan 24, 2023 at 12:20 PM Geert Uytterhoeven > > > > <geert@linux-m68k.org> wrote: > > > > > On Thu, Dec 15, 2022 at 7:23 PM Bjorn Helgaas <helgaas@kernel.org> wrote: > > > > > > From: Bjorn Helgaas <bhelgaas@google.com> > > > > > > > > > > > > Simplify __rpm_get_callback() slightly by returning as soon as the return > > > > > > value is known. No functional change intended. > > > > > > > > > > > > Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> > > > > > > > > > > Thanks for your patch, which is now commit 650bdddb6b311705 ("PM: > > > > > runtime: Simplify __rpm_get_callback()") in pm/linux-next. > > > > > > > > > > > --- a/drivers/base/power/runtime.c > > > > > > +++ b/drivers/base/power/runtime.c > > > > > > @@ -20,8 +20,7 @@ typedef int (*pm_callback_t)(struct device *); > > > > > > > > > > > > static pm_callback_t __rpm_get_callback(struct device *dev, size_t cb_offset) > > > > > > { > > > > > > - pm_callback_t cb; > > > > > > - const struct dev_pm_ops *ops; > > > > > > + const struct dev_pm_ops *ops = NULL; > > > > > > > > > > > > if (dev->pm_domain) > > > > > > ops = &dev->pm_domain->ops; > > > > > > @@ -31,18 +30,14 @@ static pm_callback_t __rpm_get_callback(struct device *dev, size_t cb_offset) > > > > > > ops = dev->class->pm; > > > > > > else if (dev->bus && dev->bus->pm) > > > > > > ops = dev->bus->pm; > > > > > > - else > > > > > > - ops = NULL; > > > > > > > > > > > > if (ops) > > > > > > - cb = *(pm_callback_t *)((void *)ops + cb_offset); > > > > > > - else > > > > > > - cb = NULL; > > > > > > + return *(pm_callback_t *)((void *)ops + cb_offset); > > > > > > > > > > This is a change in behavior in case the callback turns out to be NULL: > > > > > - before, it would fall back to the driver-specific callback below, > > > > > - after, it always returns NULL. > > > > > > > > Good point and sorry for missing this! > > > > > > > > > > > > > > > > - if (!cb && dev->driver && dev->driver->pm) > > > > > > - cb = *(pm_callback_t *)((void *)dev->driver->pm + cb_offset); > > > > > > + if (dev->driver && dev->driver->pm) > > > > > > + return *(pm_callback_t *)((void *)dev->driver->pm + cb_offset); > > > > > > > > > > > > - return cb; > > > > > > + return NULL; > > > > > > } > > > > > > > > > > > > > Something like the patch below (modulo gmail-induced whitespace > > > > breakage) should restore the previous behavior if I'm not mistaken: > > > > > > > > --- > > > > drivers/base/power/runtime.c | 9 +++++++-- > > > > 1 file changed, 7 insertions(+), 2 deletions(-) > > > > > > > > Index: linux-pm/drivers/base/power/runtime.c > > > > =================================================================== > > > > --- linux-pm.orig/drivers/base/power/runtime.c > > > > +++ linux-pm/drivers/base/power/runtime.c > > > > @@ -31,8 +31,13 @@ static pm_callback_t __rpm_get_callback( > > > > else if (dev->bus && dev->bus->pm) > > > > ops = dev->bus->pm; > > > > > > > > - if (ops) > > > > - return *(pm_callback_t *)((void *)ops + cb_offset); > > > > + if (ops) { > > > > + pm_callback_t cb; > > > > + > > > > + cb = *(pm_callback_t *)((void *)ops + cb_offset); > > > > + if (cb) > > > > + return cb; > > > > + } > > > > > > > > if (dev->driver && dev->driver->pm) > > > > return *(pm_callback_t *)((void *)dev->driver->pm + cb_offset); > > > > > > Which is now more complex than the original? > > > > Arguably so. > > > > OK, I'll drop the commit in question then, sorry Bjorn. > > Really sorry about this. Think I'm all out of brown paper bags :( > Thanks for catching this, Geert, and sorry for all the time you had to
Np, no time was wasted on debugging. I just noticed because I have some local debug code on top, which no longer applied 8^)
Gr{oetje,eeting}s,
Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
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
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