Messages in this thread | | | Date | Thu, 15 May 2014 14:47:43 -0700 | From | Guenter Roeck <> | Subject | Re: [PATCH v3 1/6] watchdog: Add API to trigger reboots |
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On Thu, May 15, 2014 at 09:50:20PM +0100, One Thousand Gnomes wrote: > > +void watchdog_do_reboot(void) > > +{ > > + if (wdd_reboot_dev) > > + wdd_reboot_dev->ops->reboot(wdd_reboot_dev); > > +} > > +EXPORT_SYMBOL(watchdog_do_reboot); > > Crashes and burns if you are unloading a watchdog just as you try to > reboot. Yes its wildly unlikely but it's still conceptually wrong. > Possibly, but how is it different to the code it replaces ?
> > > > + if (wdd->ops->reboot) > > + wdd_reboot_dev = wdd; > > + > > Two parallel registers from different bus types, parallel > register/unregister ? > Sorry, you lost me. What different bus types ?
> This feels to me like a backward step. We've gone from various device > bits leaking into the core code (where they can work all the time) to > various core code leaking into the devices which is asking for init order > problems and other races. > > Given we are talking about stuff of the order of 10-20 instructions I > think duplication is not only the lesser evil it's also smaller, more > reliable and easier to maintain. > > IMHO this is a solution looking for a problem. > Really ? To me it seems to be much cleaner than setting the pointer to arm_pm_restart directly from individual watchdog drivers. Also, and I was told that other HW may benefit from it as well.
Do I understand it correctly that you prefer watchdog drivers to set arm_pm_restart directly ? Maybe you can explain a bit why you believe that to be a superior solution.
In addition to that, while I could obviously add some locking around access to wdd_reboot_dev, existing code doesn't lock any changes to arm_pm_restart. I am somewhat at loss why setting or clearing arm_pm_restart is less of a problem that setting wdd_reboot_dev.
Thanks, Guenter
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