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From: "Guilherme G. Piccoli" <gpiccoli@linux.vnet.ibm.com>
To: linuxppc-dev@lists.ozlabs.org, gwshan@linux.vnet.ibm.com
Cc: mpe@ellerman.id.au, benh@kernel.crashing.org, paulus@samba.org,
	nfont@linux.vnet.ibm.com
Subject: [PATCH 1/2 v2] Revert "powerpc/eeh: Fix crash in eeh_add_device_early() on Cell"
Date: Wed,  6 Apr 2016 21:20:04 -0300	[thread overview]
Message-ID: <1459988405-13991-1-git-send-email-gpiccoli@linux.vnet.ibm.com> (raw)

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>
---
 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

             reply	other threads:[~2016-04-07  0:20 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-04-07  0:20 Guilherme G. Piccoli [this message]
2016-04-07  0:20 ` [PATCH 2/2 v2] powerpc/iommu: Remove the dependency on EEH struct in DDW mechanism Guilherme G. Piccoli
2016-04-07  0:48   ` Gavin Shan
2016-04-07  1:55     ` Guilherme G. Piccoli
2016-04-07  0:35 ` [PATCH 1/2 v2] Revert "powerpc/eeh: Fix crash in eeh_add_device_early() on Cell" Gavin Shan

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