Re: [PATCH 1/2 v2] Revert "powerpc/eeh: Fix crash in eeh_add_device_early() on Cell"

[Gavin Shan <gwshan@linux.vnet.ibm.com>]

On Wed, Apr 06, 2016 at 09:20:04PM -0300, Guilherme G. Piccoli wrote:
>This reverts commit 89a51df5ab1d38b257300b8ac940bbac3bb0eb9b.
>
>The function eeh_add_device_early() is used to perform EEH initialization in
>devices added later on the system, like in hotplug/DLPAR scenarios. Since the
>commit 89a51df5ab1d ("powerpc/eeh: Fix crash in eeh_add_device_early() on Cell")
>a new check was introduced in this function - Cell has no EEH capabilities
>which led to kernel oops if hotplug was performed, so checking for
>eeh_enabled() was introduced to avoid the issue.
>
>However, in architectures that EEH is present like pSeries or PowerNV, we might
>reach a case in which no PCI devices are present on boot time and so EEH is not
>initialized. Then, if a device is added via DLPAR for example,
>eeh_add_device_early() fails because eeh_enabled() is false, and EEH end up
>not being enabled at all.
>
>This reverts the aforementioned patch since a new verification was introduced by
>the commit d91dafc02f42 ("powerpc/eeh: Delay probing EEH device during hotplug")
>and so the original Cell issue does not happen anymore.
>
>Signed-off-by: Guilherme G. Piccoli <gpiccoli@linux.vnet.ibm.com>

Reviewed-by: Gavin Shan <gwshan@linux.vnet.ibm.com>

>---
> arch/powerpc/kernel/eeh.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
>diff --git a/arch/powerpc/kernel/eeh.c b/arch/powerpc/kernel/eeh.c
>index 6544017..6758484 100644
>--- a/arch/powerpc/kernel/eeh.c
>+++ b/arch/powerpc/kernel/eeh.c
>@@ -1068,7 +1068,7 @@ void eeh_add_device_early(struct pci_dn *pdn)
> 	struct pci_controller *phb;
> 	struct eeh_dev *edev = pdn_to_eeh_dev(pdn);
>
>-	if (!edev || !eeh_enabled())
>+	if (!edev)
> 		return;
>
> 	if (!eeh_has_flag(EEH_PROBE_MODE_DEVTREE))
>-- 
>2.1.0
>