From: Keir Fraser <keir.fraser@citrix.com>
Date: Tue, 24 Nov 2009 14:45:19 +0000 (+0000)
Subject: xen: Dont call msi_unmap_pirq() if did not enable msi
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=5285405772c205113d0dd6010761cbe931c85866;p=people%2Froyger%2Flinux-2.6.18-xen.git

xen: Dont call msi_unmap_pirq() if did not enable msi

When device driver unload, it may call pci_disable_msi(), if msi did
not enabled but do msi_unmap_pirq(), then later driver reload and
without msi, then will failed in request_irq() for irq_desc[irq]->chip
valie is no_irq_chip. So when did not enable msi during driver
initializing, then unloaded driver will not try to disable it.

How to reproduce it:
  At the server with QLogic 25xx, try to reload qla2xxx will hit it.

Signed-off-by: Joe Jin <joe.jin@oracle.com>
---

diff --git a/drivers/pci/msi-xen.c b/drivers/pci/msi-xen.c
index f4e3d725..30fcaa94 100644
--- a/drivers/pci/msi-xen.c
+++ b/drivers/pci/msi-xen.c
@@ -618,6 +618,7 @@ int pci_enable_msi(struct pci_dev* dev)
 			return ret;
 
 		dev->irq = evtchn_map_pirq(-1, dev->irq);
+		dev->msi_enabled = 1;
 		msi_dev_entry->default_irq = temp;
 
 		return ret;
@@ -662,9 +663,15 @@ void pci_disable_msi(struct pci_dev* dev)
 
 #ifdef CONFIG_XEN_PCIDEV_FRONTEND
 	if (!is_initial_xendomain()) {
+		if (!(dev->msi_enabled)) {
+			printk(KERN_INFO "PCI: %s: Device did not enabled MSI.\n",
+			       pci_name(dev));
+			return;
+		}
 		evtchn_map_pirq(dev->irq, 0);
 		pci_frontend_disable_msi(dev);
 		dev->irq = msi_dev_entry->default_irq;
+		dev->msi_enabled = 0;
 		return;
 	}
 #endif
@@ -673,6 +680,12 @@ void pci_disable_msi(struct pci_dev* dev)
 	if (!pos)
 		return;
 
+	if (!(dev->msi_enabled)) {
+		printk(KERN_INFO "PCI: %s: Device did not enabled MSI.\n",
+		       pci_name(dev));
+		return;
+	}
+ 
 	pirq = dev->irq;
 	/* Restore dev->irq to its default pin-assertion vector */
 	dev->irq = msi_dev_entry->default_irq;