From: AMEET M. PARANJAPE <aparanja@redhat.com>
Date: Thu, 19 Feb 2009 14:21:36 -0500
Subject: [ppc64] eeh: disable/enable LSI interrupts
Message-id: 20090219192000.15494.21854.sendpatchset@squad5-lp1.lab.bos.redhat.com
O-Subject: [PATCH RHEL5.4 BZ475696] Only disable/enable LSI interrupts in EEH
Bugzilla: 475696
RH-Acked-by: David Howells <dhowells@redhat.com>

RHBZ#:
======
https://bugzilla.redhat.com/show_bug.cgi?id=475696

Description:
===========
The EEH code disables and enables interrupts during the
device recovery process.  This is unnecessary for MSI
and MSI-X interrupts because they are effectively disabled
by the DMA Stopped state when an EEH error occurs.  The
current code is also incorrect for MSI-X interrupts.  It
doesn't take into account that MSI-X interrupts are tracked
in a different way than LSI/MSI interrupts.  This patch
ensures only LSI interrupts are disabled/enabled.

RHEL Version Found:
================
RHEL 5.3

kABI Status:
============
No symbols were harmed.

Brew:
=====
Built on all platforms.
http://brewweb.devel.redhat.com/brew/taskinfo?taskID=169433

Upstream Status:
================
http://git.kernel.org/?p=linux/kernel/git/sfr/linux-next.git;a=commit;h=8535ef05a6904429ce72671c3035dbf05e6d5edf

Test Status:
============
Without this patch systems running with network devices that use LSI, MSI and
MSI-X interrupts would not recover properly from error events.  With this patch
those network devices recover fine.

===============================================================
Ameet Paranjape 978-392-3903 ext 23903
IBM on-site partner

Proposed Patch:
===============

diff --git a/arch/powerpc/platforms/pseries/eeh_driver.c b/arch/powerpc/platforms/pseries/eeh_driver.c
index 36cc395..e126d5d 100644
--- a/arch/powerpc/platforms/pseries/eeh_driver.c
+++ b/arch/powerpc/platforms/pseries/eeh_driver.c
@@ -76,6 +76,40 @@ static int irq_in_use(unsigned int irq)
 	return rc;
 }
 
+/**
+ * eeh_disable_irq - disable interrupt for the recovering device
+ */
+static void eeh_disable_irq(struct pci_dev *dev)
+{
+	struct device_node *dn = pci_device_to_OF_node(dev);
+
+	/* Don't disable MSI and MSI-X interrupts. They are
+	 * effectively disabled by the DMA Stopped state 
+	 * when an EEH error occurs.
+	*/
+	if (dev->msi_enabled || dev->msix_enabled)
+		return;
+
+	if (!irq_in_use(dev->irq))
+		return;
+
+	PCI_DN(dn)->eeh_mode |= EEH_MODE_IRQ_DISABLED;
+	disable_irq_nosync(dev->irq);
+}
+
+/**
+ * eeh_enable_irq - enable interrupt for the recovering device
+ */
+static void eeh_enable_irq(struct pci_dev *dev)
+{
+	struct device_node *dn = pci_device_to_OF_node(dev);
+
+	if ((PCI_DN(dn)->eeh_mode) & EEH_MODE_IRQ_DISABLED) {
+		PCI_DN(dn)->eeh_mode &= ~EEH_MODE_IRQ_DISABLED;
+		enable_irq(dev->irq);
+	}
+}
+
 /* ------------------------------------------------------- */
 /**
  * eeh_report_error - report pci error to each device driver
@@ -95,11 +129,8 @@ static void eeh_report_error(struct pci_dev *dev, void *userdata)
 	if (!driver)
 		return;
 
-	if (irq_in_use (dev->irq)) {
-		struct device_node *dn = pci_device_to_OF_node(dev);
-		PCI_DN(dn)->eeh_mode |= EEH_MODE_IRQ_DISABLED;
-		disable_irq_nosync(dev->irq);
-	}
+	eeh_disable_irq(dev);
+
 	if (!driver->err_handler ||
 	    !driver->err_handler->error_detected)
 		return;
@@ -144,15 +175,12 @@ static void eeh_report_reset(struct pci_dev *dev, void *userdata)
 {
 	enum pci_ers_result rc, *res = userdata;
 	struct pci_driver *driver = dev->driver;
-	struct device_node *dn = pci_device_to_OF_node(dev);
 
 	if (!driver)
 		return;
 
-	if ((PCI_DN(dn)->eeh_mode) & EEH_MODE_IRQ_DISABLED) {
-		PCI_DN(dn)->eeh_mode &= ~EEH_MODE_IRQ_DISABLED;
-		enable_irq(dev->irq);
-	}
+	eeh_enable_irq(dev);
+
 	if (!driver->err_handler ||
 	    !driver->err_handler->slot_reset)
 		return;
@@ -171,17 +199,14 @@ static void eeh_report_reset(struct pci_dev *dev, void *userdata)
 static void eeh_report_resume(struct pci_dev *dev, void *userdata)
 {
 	struct pci_driver *driver = dev->driver;
-	struct device_node *dn = pci_device_to_OF_node(dev);
 
 	dev->error_state = pci_channel_io_normal;
 
 	if (!driver)
 		return;
 
-	if ((PCI_DN(dn)->eeh_mode) & EEH_MODE_IRQ_DISABLED) {
-		PCI_DN(dn)->eeh_mode &= ~EEH_MODE_IRQ_DISABLED;
-		enable_irq(dev->irq);
-	}
+	eeh_enable_irq(dev);
+
 	if (!driver->err_handler ||
 	    !driver->err_handler->resume)
 		return;
@@ -205,15 +230,12 @@ static void eeh_report_failure(struct pci_dev *dev, void *userdata)
 	if (!driver)
 		return;
 
-	if (irq_in_use (dev->irq)) {
-		struct device_node *dn = pci_device_to_OF_node(dev);
-		PCI_DN(dn)->eeh_mode |= EEH_MODE_IRQ_DISABLED;
-		disable_irq_nosync(dev->irq);
-	}
-	if (!driver->err_handler)
-		return;
-	if (!driver->err_handler->error_detected)
+	eeh_disable_irq(dev);
+
+	if (!driver->err_handler ||
+	    !driver->err_handler->error_detected)
 		return;
+
 	driver->err_handler->error_detected(dev, pci_channel_io_perm_failure);
 }