[PATCH v2 2/7] powerpc/kernel: Add uevents in EEH error/resume

[Bjorn Helgaas]

[+cc Keith, Gabriele, Dongdong]

On Mon, Dec 18, 2017 at 04:38:03PM -0600, Bryant G. Ly wrote:
> Devices can go offline when EEH is reported. This patch adds
> a change to the kernel object and lets udev know of error.
> When device resumes a change is also set reporting device as
> online. Therefore, EEH events are better propagated to user
> space for devices in powerpc arch.

I'm on vacation and can't review this in detail, but I wonder if you
can compare this with the uevents we emit for DPC, AER, and hotplug
events (if any).  I hope we don't end up with userspace having to be
aware of the differences between EEH, DPC, AER, etc.

>From a very quick look, I only see a few uevents even mentioned in
drivers/pci: KOBJ_ADD in __pci_hp_register() and KOBJ_CHANGE in the
SR-IOV code.  I'm worried that we're missing some important uevents in
the PCI core.  That's not an argument against what you're doing here;
it just would be nice to fill in any missing pieces in the core also,
and hopefully make them consistent with these EEH events.

> Signed-off-by: Bryant G. Ly <bryantly at linux.vnet.ibm.com>
> Signed-off-by: Juan J. Alvarez <jjalvare at linux.vnet.ibm.com>
> ---
>  arch/powerpc/kernel/eeh_driver.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/arch/powerpc/kernel/eeh_driver.c b/arch/powerpc/kernel/eeh_driver.c
> index 3c0fa99c5533..9d4e8177c2e0 100644
> --- a/arch/powerpc/kernel/eeh_driver.c
> +++ b/arch/powerpc/kernel/eeh_driver.c
> @@ -204,6 +204,7 @@ static void *eeh_report_error(void *data, void *userdata)
>  	struct pci_dev *dev = eeh_dev_to_pci_dev(edev);
>  	enum pci_ers_result rc, *res = userdata;
>  	struct pci_driver *driver;
> +	char *envp[] = {"EVENT=EEH_ERROR", "ONLINE=0", NULL};
>  
>  	if (!dev || eeh_dev_removed(edev) || eeh_pe_passed(edev->pe))
>  		return NULL;
> @@ -228,6 +229,7 @@ static void *eeh_report_error(void *data, void *userdata)
>  
>  	edev->in_error = true;
>  	eeh_pcid_put(dev);
> +	kobject_uevent_env(&dev->dev.kobj, KOBJ_CHANGE, envp);
>  	return NULL;
>  }
>  
> @@ -358,6 +360,7 @@ static void *eeh_report_resume(void *data, void *userdata)
>  	struct pci_dev *dev = eeh_dev_to_pci_dev(edev);
>  	bool was_in_error;
>  	struct pci_driver *driver;
> +	char *envp[] = {"EVENT=EEH_RESUME", "ONLINE=1", NULL};
>  
>  	if (!dev || eeh_dev_removed(edev) || eeh_pe_passed(edev->pe))
>  		return NULL;
> @@ -381,6 +384,7 @@ static void *eeh_report_resume(void *data, void *userdata)
>  	driver->err_handler->resume(dev);
>  
>  	eeh_pcid_put(dev);
> +	kobject_uevent_env(&dev->dev.kobj, KOBJ_CHANGE, envp);
>  	return NULL;
>  }
>  
> @@ -397,6 +401,7 @@ static void *eeh_report_failure(void *data, void *userdata)
>  	struct eeh_dev *edev = (struct eeh_dev *)data;
>  	struct pci_dev *dev = eeh_dev_to_pci_dev(edev);
>  	struct pci_driver *driver;
> +	char * envp[] = {"EVENT=EEH_PERMANENT_FAILURE", "ONLINE=0", NULL};
>  
>  	if (!dev || eeh_dev_removed(edev) || eeh_pe_passed(edev->pe))
>  		return NULL;
> @@ -415,6 +420,7 @@ static void *eeh_report_failure(void *data, void *userdata)
>  
>  	driver->err_handler->error_detected(dev, pci_channel_io_perm_failure);
>  
> +	kobject_uevent_env(&dev->dev.kobj, KOBJ_CHANGE, envp);
>  	eeh_pcid_put(dev);
>  	return NULL;
>  }
> -- 
> 2.14.3 (Apple Git-98)
>