[PATCH] kernel: cpu: send CPU_UP_CANCELLED notification

[PATCH] kernel: cpu: send CPU_UP_CANCELLED notification

[Channagoud Kadabi]

If any of the callbacks during cpu up fail undo_cpu_up calls the
teardown call backs to rollback states but does not send
CPU_UP_CANCELLED. As on 4.9 kernel some drivers still use the
notification mechanism for cpu hotplug we need to send
CPU_UP_CANCELLED notification so drivers can rollback whatever
they did during cpu up.

Signed-off-by: Channagoud Kadabi <ckadabi@codeaurora.org>
---
 kernel/cpu.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/cpu.c b/kernel/cpu.c
index 8f52977..ade5bb2 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -494,6 +494,7 @@ static int cpuhp_up_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st,
 		if (ret) {
 			st->target = prev_state;
 			undo_cpu_up(cpu, st);
+			cpu_notify(CPU_UP_CANCELED, cpu);
 			break;
 		}
 	}
-- 
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a Linux Foundation Collaborative Project

Re: [PATCH] kernel: cpu: send CPU_UP_CANCELLED notification

[Greg KH]

On Fri, Jul 14, 2017 at 02:50:28PM -0700, Channagoud Kadabi wrote:
> If any of the callbacks during cpu up fail undo_cpu_up calls the
> teardown call backs to rollback states but does not send
> CPU_UP_CANCELLED. As on 4.9 kernel some drivers still use the
> notification mechanism for cpu hotplug we need to send
> CPU_UP_CANCELLED notification so drivers can rollback whatever
> they did during cpu up.
> 
> Signed-off-by: Channagoud Kadabi <ckadabi@codeaurora.org>
> ---
>  kernel/cpu.c | 1 +
>  1 file changed, 1 insertion(+)

<formletter>

This is not the correct way to submit patches for inclusion in the
stable kernel tree.  Please read:
    https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
for how to do this properly.

</formletter>

Re: [PATCH] kernel: cpu: send CPU_UP_CANCELLED notification

[kbuild test robot]

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Hi Channagoud,

[auto build test ERROR on linus/master]
[also build test ERROR on v4.12 next-20170714]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Channagoud-Kadabi/kernel-cpu-send-CPU_UP_CANCELLED-notification/20170715-152954
config: x86_64-randconfig-x019-201728 (attached as .config)
compiler: gcc-6 (Debian 6.2.0-3) 6.2.0 20160901
reproduce:
        # save the attached .config to linux build tree
        make ARCH=x86_64 

All errors (new ones prefixed by >>):

   kernel/cpu.c: In function 'cpuhp_up_callbacks':
>> kernel/cpu.c:368:4: error: implicit declaration of function 'cpu_notify' [-Werror=implicit-function-declaration]
       cpu_notify(CPU_UP_CANCELED, cpu);
       ^~~~~~~~~~
>> kernel/cpu.c:368:15: error: 'CPU_UP_CANCELED' undeclared (first use in this function)
       cpu_notify(CPU_UP_CANCELED, cpu);
                  ^~~~~~~~~~~~~~~
   kernel/cpu.c:368:15: note: each undeclared identifier is reported only once for each function it appears in
   cc1: some warnings being treated as errors

vim +/cpu_notify +368 kernel/cpu.c

   355	
   356	static int cpuhp_up_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st,
   357				      enum cpuhp_state target)
   358	{
   359		enum cpuhp_state prev_state = st->state;
   360		int ret = 0;
   361	
   362		while (st->state < target) {
   363			st->state++;
   364			ret = cpuhp_invoke_callback(cpu, st->state, true, NULL);
   365			if (ret) {
   366				st->target = prev_state;
   367				undo_cpu_up(cpu, st);
 > 368				cpu_notify(CPU_UP_CANCELED, cpu);
   369				break;
   370			}
   371		}
   372		return ret;
   373	}
   374	

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

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