Messages in this thread Patch in this message | | | From | "Rafael J. Wysocki" <> | Date | Tue, 24 Jan 2023 15:07:14 +0100 | Subject | Re: [PATCH] PM: runtime: Simplify __rpm_get_callback() |
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On Tue, Jan 24, 2023 at 12:20 PM Geert Uytterhoeven <geert@linux-m68k.org> wrote: > > Hi Bjorn, > > 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);
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