From: Danny Feng <dfeng@redhat.com>
Date: Fri, 18 Sep 2009 01:26:44 -0400
Subject: [x86] finish sysdata conversion
Message-id: 20090918052703.27603.88351.sendpatchset@danny
O-Subject: [PATCH RHEL5.5] finish i386 and x86-64 sysdata conversion
Bugzilla: 519633
RH-Acked-by: Prarit Bhargava <prarit@redhat.com>
RH-Acked-by: Chris Lalancette <clalance@redhat.com>

RHBZ#:
https://bugzilla.redhat.com/show_bug.cgi?id=519633

Description:
Reading /sys/class/pci_bus/0000:ff/cpuaffinity (using cat or a similar
function) will cause the kernel to crash and the system to reboot.

After crash analysis, we know pci_bus->sysdata is NULL, then trying to
visit pci_bus->sysdata->node, panic results.

sysdata changed by recent commit [x86] PCI domain support (103d69a0).
It is no longer just an integer containing the node, it is now a structure
containing the node and other data. However, it seems that we do not
always initialise this sysdata before we probe the device. then we may get
a NULL sysdata(pci_scan_bus with NULL sysdata).

Later commit in upstream has finished i386 and x86-64 sysdata conversion,
which will initialise sysdata well. Thus sysdata will not be NULL anymore.

Upstream status:
http://git.kernel.org/?p=linux/kernel/git/stable/linux-2.6.23.y.git;a=commit;h=73c59afc65cfa50c3362b9ce1ec151a79c41dd8e

KABI:
no harm

Brew Build:
https://brewweb.devel.redhat.com/taskinfo?taskID=1991444

Test status:
Customer tested my test rpm and they are no longer seeing the panic.

diff --git a/arch/i386/pci/common.c b/arch/i386/pci/common.c
index 8373c7e..2007535 100644
--- a/arch/i386/pci/common.c
+++ b/arch/i386/pci/common.c
@@ -526,3 +526,26 @@ void pcibios_disable_device (struct pci_dev *dev)
 	if (pcibios_disable_irq)
 		pcibios_disable_irq(dev);
 }
+
+struct pci_bus *pci_scan_bus_with_sysdata(int busno)
+{
+	struct pci_bus *bus = NULL;
+	struct pci_sysdata *sd;
+
+	/*
+	 * Allocate per-root-bus (not per bus) arch-specific data.
+	 * TODO: leak; this memory is never freed.
+	 * It's arguable whether it's worth the trouble to care.
+	 */
+	sd = kzalloc(sizeof(*sd), GFP_KERNEL);
+	if (!sd) {
+		printk(KERN_ERR "PCI: OOM, skipping PCI bus %02x\n", busno);
+		return NULL;
+	}
+	sd->node = -1;
+	bus = pci_scan_bus(busno, &pci_root_ops, sd);
+	if (!bus)
+		kfree(sd);
+
+	return bus;
+}
diff --git a/arch/i386/pci/fixup.c b/arch/i386/pci/fixup.c
index cb0cbb8..3cb56c5 100644
--- a/arch/i386/pci/fixup.c
+++ b/arch/i386/pci/fixup.c
@@ -25,9 +25,9 @@ static void __devinit pci_fixup_i450nx(struct pci_dev *d)
 		pci_read_config_byte(d, reg++, &subb);
 		DBG("i450NX PXB %d: %02x/%02x/%02x\n", pxb, busno, suba, subb);
 		if (busno)
-			pci_scan_bus(busno, &pci_root_ops, NULL);	/* Bus A */
+			pci_scan_bus_with_sysdata(busno);	/* Bus A */
 		if (suba < subb)
-			pci_scan_bus(suba+1, &pci_root_ops, NULL);	/* Bus B */
+			pci_scan_bus_with_sysdata(suba+1);	/* Bus B */
 	}
 	pcibios_last_bus = -1;
 }
@@ -42,7 +42,7 @@ static void __devinit pci_fixup_i450gx(struct pci_dev *d)
 	u8 busno;
 	pci_read_config_byte(d, 0x4a, &busno);
 	printk(KERN_INFO "PCI: i440KX/GX host bridge %s: secondary bus %02x\n", pci_name(d), busno);
-	pci_scan_bus(busno, &pci_root_ops, NULL);
+	pci_scan_bus_with_sysdata(busno);
 	pcibios_last_bus = -1;
 }
 DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82454GX, pci_fixup_i450gx);
diff --git a/arch/i386/pci/irq.c b/arch/i386/pci/irq.c
index d4b19d2..d6f81e4 100644
--- a/arch/i386/pci/irq.c
+++ b/arch/i386/pci/irq.c
@@ -138,8 +138,9 @@ static void __init pirq_peer_trick(void)
 	for(i = 1; i < 256; i++) {
 		if (!busmap[i] || pci_find_bus(0, i))
 			continue;
-		if (pci_scan_bus(i, &pci_root_ops, NULL))
-			printk(KERN_INFO "PCI: Discovered primary peer bus %02x [IRQ]\n", i);
+		if (pci_scan_bus_with_sysdata(i))
+			printk(KERN_INFO "PCI: Discovered primary peer "
+			       "bus %02x [IRQ]\n", i);
 	}
 	pcibios_last_bus = -1;
 }
diff --git a/arch/i386/pci/legacy.c b/arch/i386/pci/legacy.c
index 273384f..c6920aa 100644
--- a/arch/i386/pci/legacy.c
+++ b/arch/i386/pci/legacy.c
@@ -19,11 +19,6 @@ static void __devinit pcibios_fixup_peer_bridges(void)
 
 	for (n=0; n <= pcibios_last_bus; n++) {
 		u32 l;
-		struct pci_sysdata *sd;
-
-		sd = kzalloc(sizeof(&sd), GFP_KERNEL);
-		if (!sd)
-			panic("Cannot allocate PCI domain sysdata");
 		if (pci_find_bus(0, n))
 			continue;
 		for (devfn = 0; devfn < 256; devfn += 8) {
@@ -31,8 +26,7 @@ static void __devinit pcibios_fixup_peer_bridges(void)
 			    l != 0x0000 && l != 0xffff) {
 				DBG("Found device at %02x:%02x [%04x]\n", n, devfn, l);
 				printk(KERN_INFO "PCI: Discovered peer bus %02x\n", n);
-				if (!pci_scan_bus(n, &pci_root_ops, sd))
-					kfree(sd);
+				pci_scan_bus_with_sysdata(n);
 				break;
 			}
 		}
diff --git a/arch/i386/pci/numa.c b/arch/i386/pci/numa.c
index adbe17a..f5f165f 100644
--- a/arch/i386/pci/numa.c
+++ b/arch/i386/pci/numa.c
@@ -96,10 +96,14 @@ static void __devinit pci_fixup_i450nx(struct pci_dev *d)
 		pci_read_config_byte(d, reg++, &suba);
 		pci_read_config_byte(d, reg++, &subb);
 		DBG("i450NX PXB %d: %02x/%02x/%02x\n", pxb, busno, suba, subb);
-		if (busno)
-			pci_scan_bus(QUADLOCAL2BUS(quad,busno), &pci_root_ops, NULL);	/* Bus A */
-		if (suba < subb)
-			pci_scan_bus(QUADLOCAL2BUS(quad,suba+1), &pci_root_ops, NULL);	/* Bus B */
+		if (busno) {
+			/* Bus A */
+			pci_scan_bus_with_sysdata(QUADLOCAL2BUS(quad, busno));
+		}
+		if (suba < subb) {
+			/* Bus B */
+			pci_scan_bus_with_sysdata(QUADLOCAL2BUS(quad, suba+1));
+		}
 	}
 	pcibios_last_bus = -1;
 }
@@ -123,8 +127,7 @@ static int __init pci_numa_init(void)
 				continue;
 			printk("Scanning PCI bus %d for quad %d\n", 
 				QUADLOCAL2BUS(quad,0), quad);
-			pci_scan_bus(QUADLOCAL2BUS(quad,0), 
-				&pci_root_ops, NULL);
+			pci_scan_bus_with_sysdata(QUADLOCAL2BUS(quad, 0));
 		}
 	return 0;
 }
diff --git a/arch/i386/pci/pci.h b/arch/i386/pci/pci.h
index 2c3ac48..c82a035 100644
--- a/arch/i386/pci/pci.h
+++ b/arch/i386/pci/pci.h
@@ -101,6 +101,8 @@ extern void pci_pcbios_init(void);
 extern void pci_mmcfg_init(void);
 extern void pcibios_sort(void);
 
+/* scan a bus after allocating a pci_sysdata for it */
+extern struct pci_bus *pci_scan_bus_with_sysdata(int busno);
 
 /*
  * AMD Fam10h CPUs are buggy, and cannot access MMIO config space
diff --git a/arch/i386/pci/visws.c b/arch/i386/pci/visws.c
index f1b486d..8ecb1c7 100644
--- a/arch/i386/pci/visws.c
+++ b/arch/i386/pci/visws.c
@@ -101,8 +101,8 @@ static int __init pcibios_init(void)
 		"bridge B (PIIX4) bus: %u\n", pci_bus1, pci_bus0);
 
 	raw_pci_ops = &pci_direct_conf1;
-	pci_scan_bus(pci_bus0, &pci_root_ops, NULL);
-	pci_scan_bus(pci_bus1, &pci_root_ops, NULL);
+	pci_scan_bus_with_sysdata(pci_bus0);
+	pci_scan_bus_with_sysdata(pci_bus1);
 	pci_fixup_irqs(visws_swizzle, visws_map_irq);
 	pcibios_resource_survey();
 	return 0;