[3.11.y.z extended stable] Patch "powerpc/powernv: Rework EEH reset" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    powerpc/powernv: Rework EEH reset

to the linux-3.11.y-queue branch of the 3.11.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.11.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.11.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From d8c4c14fb7c1093425f66be10ae92de084061b56 Mon Sep 17 00:00:00 2001
From: Gavin Shan <shangw at linux.vnet.ibm.com>
Date: Wed, 12 Feb 2014 15:24:54 +0800
Subject: powerpc/powernv: Rework EEH reset

commit 5b2e198e50f6ba57081586b853163ea1bb95f1a8 upstream.

When doing reset in order to recover the affected PE, we issue
hot reset on PE primary bus if it's not root bus. Otherwise, we
issue hot or fundamental reset on root port or PHB accordingly.
For the later case, we didn't cover the situation where PE only
includes root port and it potentially causes kernel crash upon
EEH error to the PE.

The patch reworks the logic of EEH reset to improve the code
readability and also avoid the kernel crash.

Reported-by: Thadeu Lima de Souza Cascardo <cascardo at linux.vnet.ibm.com>
Signed-off-by: Gavin Shan <shangw at linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh at kernel.crashing.org>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 arch/powerpc/platforms/powernv/eeh-ioda.c | 29 ++++-------------------------
 1 file changed, 4 insertions(+), 25 deletions(-)

diff --git a/arch/powerpc/platforms/powernv/eeh-ioda.c b/arch/powerpc/platforms/powernv/eeh-ioda.c
index 0cd1c4a..d972157 100644
--- a/arch/powerpc/platforms/powernv/eeh-ioda.c
+++ b/arch/powerpc/platforms/powernv/eeh-ioda.c
@@ -470,8 +470,7 @@ static int ioda_eeh_bridge_reset(struct pci_controller *hose,
 static int ioda_eeh_reset(struct eeh_pe *pe, int option)
 {
 	struct pci_controller *hose = pe->phb;
-	struct eeh_dev *edev;
-	struct pci_dev *dev;
+	struct pci_bus *bus;
 	int ret;

 	/*
@@ -500,31 +499,11 @@ static int ioda_eeh_reset(struct eeh_pe *pe, int option)
 	if (pe->type & EEH_PE_PHB) {
 		ret = ioda_eeh_phb_reset(hose, option);
 	} else {
-		if (pe->type & EEH_PE_DEVICE) {
-			/*
-			 * If it's device PE, we didn't refer to the parent
-			 * PCI bus yet. So we have to figure it out indirectly.
-			 */
-			edev = list_first_entry(&pe->edevs,
-					struct eeh_dev, list);
-			dev = eeh_dev_to_pci_dev(edev);
-			dev = dev->bus->self;
-		} else {
-			/*
-			 * If it's bus PE, the parent PCI bus is already there
-			 * and just pick it up.
-			 */
-			dev = pe->bus->self;
-		}
-
-		/*
-		 * Do reset based on the fact that the direct upstream bridge
-		 * is root bridge (port) or not.
-		 */
-		if (dev->bus->number == 0)
+		bus = eeh_pe_bus_get(pe);
+		if (pci_is_root_bus(bus))
 			ret = ioda_eeh_root_reset(hose, option);
 		else
-			ret = ioda_eeh_bridge_reset(hose, dev, option);
+			ret = ioda_eeh_bridge_reset(hose, bus->self, option);
 	}

 	return ret;
--
1.9.0