Messages in this thread | | | Date | Tue, 25 Jun 2013 17:31:27 +0800 | From | Chen Gang <> | Subject | Re: [PATCH] arch: s390: kernel: reset 'c->hotpluggable' when failure occurs |
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On 06/25/2013 05:09 PM, Heiko Carstens wrote: > On Tue, Jun 25, 2013 at 03:24:09PM +0800, Chen Gang wrote: >> On 06/25/2013 02:48 PM, Heiko Carstens wrote: >>> On Tue, Jun 25, 2013 at 09:46:45AM +0800, Chen Gang wrote: >>>>> When smp_add_present_cpu() fails, it has reset all things excluding >>>>> 'c->hotpluggable', so need reset it as original state completely. >>>>> >>>>> + c->hotpluggable = 0; >>>>> return rc; >>> No, that doesn't make sense. All cpus on s390 are always hotplugable. >>> It really doesn't matter if the value of this field is 0 or 1 after >>> an error. >>> >> >> If so, is it better to set 'c->hotpluggable' for all cpus on s390 during >> initializing ? > > No, just leave the code as it is. >
Currently we have 3 possible states for 'struct cpu': initialized, and set hotplugable. unitialized, and set hotplugable. unitialized, and unset hotplugable.
Either 2nd or 3rd is inconsistent.
The cpu_is_hotplugable() will be used in kernel/rcutorture.c. I do not know whether it will cause issue or not, but it seems dangerous when __smp_rescan_cpus() has already called, and has some unsucessfull call of smp_add_present_cpu().
Please help check.
Thanks. -- Chen Gang
Asianux Corporation
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