[PATCH V2] error path improvement in dlpar add

[wenxiong@linux.ibm.com]

From: Wen Xiong <wenxiong@linux.ibm.com>

When doing a dlpar adding a device back, expect not loading device driver
if claiming pci resource failed.

Validating PHB DLPAR capability...yes.
[ 4928.798012] pci_bus 0187:c0: root bus resource [bus c0-ff]
[ 4928.798038] pci 0187:c0:00.0: No hypervisor support for SR-IOV on this device, IOV BARs disabled.
[ 4928.815867] pci 0187:c0:00.0: BAR 0 [mem 0xb0020000-0xb0027fff 64bit]: can't claim; no compatible bridge window

---> Expect to exit if claiming resources fails(BAR0)

[ 4928.815899] pci 0187:c0:00.0: ROM [mem 0xb0000000-0xb001ffff]: can't claim; no compatible bridge window

--->Expect to exit if claiming resources fails(ROM), don't load device
driver anymore, showed "dlpar add failed"

[ 4928.815913] pci 0187:c0:00.0: ROM [mem 0x40000000000-0x4000001ffff]: assigned
[ 4928.815923] pci 0187:c0:00.0: BAR 0 [mem 0x40800000000-0x40800007fff 64bit]: assigned
[ 4928.816220] pci 0187:c0:00.0: BAR 0: error updating (0x00000004 != 0xffffffff)
[ 4928.816364] pci 0187:c0:00.0: BAR 0: error updating (high 0x00060238 != 0xffffffff)
[ 4928.816839] pci 0187:c0:00.0: ibm,query-pe-dma-windows(53) b00000 8000000 20000187 returned -3, lb=0 ps=0 wn=0
[ 4928.816855] pci 0187:c0:00.0: spapr_tce_init_table_group: query_ddw failed
[ 4928.816871] pci 0187:c0:00.0: Adding to iommu group 1
[ 4928.816952] pci 0187:c0:00.0: of_irq_parse_pci: no interrupt-map found, INTx interrupts not available
[ 4928.818135] nvme 0187:c0:00.0: ibm,query-pe-dma-windows(53) b00000 8000000 20000187 returned -3, lb=0 ps=0 wn=0
[ 4928.818284] nvme nvme1: pci function 0187:c0:00.0
[ 4928.819321] rpaphp: Slot [U78DB.ND0.WZS08E2-P1-C7] registered
[ 4928.819338] rpadlpar_io: slot PHB 391 added

With adding error path checking, didn't load the device driver anymore
if claiming resources failed.

Validating PHB DLPAR capability...yes.
[  260.414453] PCI host bridge /pci@800000020000187  ranges:
[  260.414473]  MEM 0x0000040000000000..0x0000040007ffffff -> 0x00000000b8000000
[  260.414480]  MEM 0x0000040800000000..0x0000040fffffffff -> 0x0006023800000000
[  260.414915] PCI host bridge to bus 0187:c0
[  260.414922] pci_bus 0187:c0: root bus resource [mem 0x40000000000-0x40007ffffff] (bus address [0xb8000000-0xbfffffff])
[  260.414929] pci_bus 0187:c0: root bus resource [mem 0x40800000000-0x40fffffffff 64bit] (bus address [0x6023800000000-0x6023fffffffff])
[  260.414936] pci_bus 0187:c0: root bus resource [bus c0-ff]
[  260.414948] pci 0187:c0:00.0: No hypervisor support for SR-IOV on this device, IOV BARs disabled.
[  260.423439] pci 0187:c0:00.0: BAR 0 [mem 0xb0020000-0xb0027fff 64bit]: can't claim; no compatible bridge window
[  260.423463] after pci_cliam_Resource=-22   ----> pci_claim_resources fails.

[  260.423471] rpadlpar_io: slot PHB 391 added failed rc=-5  -----> added failed.

Signed-off-by: Wen Xiong <wenxiong@linux.ibm.com>
Reviewed-by: Haren Myneni <haren@linux.ibm.com>
Reviewed-by: Tyrel Datwyler <tyreld@linux.ibm.com>
---
 arch/powerpc/include/asm/pci.h             |  4 ++--
 arch/powerpc/kernel/pci-common.c           | 23 +++++++++++++++++-----
 arch/powerpc/kernel/pci-hotplug.c          |  5 ++++-
 arch/powerpc/platforms/pseries/pci_dlpar.c |  3 ++-
 drivers/pci/hotplug/rpadlpar_core.c        |  7 ++++++-
 5 files changed, 32 insertions(+), 10 deletions(-)

diff --git a/arch/powerpc/include/asm/pci.h b/arch/powerpc/include/asm/pci.h
index 46a9c4491ed0..ebeb912a92bf 100644
--- a/arch/powerpc/include/asm/pci.h
+++ b/arch/powerpc/include/asm/pci.h
@@ -86,9 +86,9 @@ extern void pci_adjust_legacy_attr(struct pci_bus *bus,
 				   enum pci_mmap_state mmap_type);
 #define HAVE_PCI_LEGACY	1
 
-extern void pcibios_claim_one_bus(struct pci_bus *b);
+extern int pcibios_claim_one_bus(struct pci_bus *b);
 
-extern void pcibios_finish_adding_to_bus(struct pci_bus *bus);
+extern int pcibios_finish_adding_to_bus(struct pci_bus *bus);
 
 extern void pcibios_resource_survey(void);
 
diff --git a/arch/powerpc/kernel/pci-common.c b/arch/powerpc/kernel/pci-common.c
index eac84d687b53..b16f43c7f02e 100644
--- a/arch/powerpc/kernel/pci-common.c
+++ b/arch/powerpc/kernel/pci-common.c
@@ -1446,10 +1446,11 @@ void __init pcibios_resource_survey(void)
  * rest of the code later, for now, keep it as-is as our main
  * resource allocation function doesn't deal with sub-trees yet.
  */
-void pcibios_claim_one_bus(struct pci_bus *bus)
+int pcibios_claim_one_bus(struct pci_bus *bus)
 {
 	struct pci_dev *dev;
 	struct pci_bus *child_bus;
+	int ret = 0;
 
 	list_for_each_entry(dev, &bus->devices, bus_list) {
 		struct resource *r;
@@ -1462,15 +1463,20 @@ void pcibios_claim_one_bus(struct pci_bus *bus)
 			pr_debug("PCI: Claiming %s: Resource %d: %pR\n",
 				 pci_name(dev), i, r);
 
-			if (pci_claim_resource(dev, i) == 0)
+			ret = pci_claim_resource(dev, i);
+			if (ret == 0)
 				continue;
+			else
+				return ret;
 
 			pci_claim_bridge_resource(dev, i);
 		}
 	}
 
 	list_for_each_entry(child_bus, &bus->children, node)
-		pcibios_claim_one_bus(child_bus);
+		ret = pcibios_claim_one_bus(child_bus);
+
+	return ret;
 }
 EXPORT_SYMBOL_GPL(pcibios_claim_one_bus);
 
@@ -1481,14 +1487,19 @@ EXPORT_SYMBOL_GPL(pcibios_claim_one_bus);
  * added to a bus, this include calling it for a PHB that is just
  * being added
  */
-void pcibios_finish_adding_to_bus(struct pci_bus *bus)
+int pcibios_finish_adding_to_bus(struct pci_bus *bus)
 {
+	int ret = 0;
+
 	pr_debug("PCI: Finishing adding to hotplug bus %04x:%02x\n",
 		 pci_domain_nr(bus), bus->number);
 
 	/* Allocate bus and devices resources */
 	pcibios_allocate_bus_resources(bus);
-	pcibios_claim_one_bus(bus);
+	ret = pcibios_claim_one_bus(bus);
+	if (ret)
+		return ret;
+
 	if (!pci_has_flag(PCI_PROBE_ONLY)) {
 		if (bus->self)
 			pci_assign_unassigned_bridge_resources(bus->self);
@@ -1498,6 +1509,8 @@ void pcibios_finish_adding_to_bus(struct pci_bus *bus)
 
 	/* Add new devices to global lists.  Register in proc, sysfs. */
 	pci_bus_add_devices(bus);
+
+	return ret;
 }
 EXPORT_SYMBOL_GPL(pcibios_finish_adding_to_bus);
 
diff --git a/arch/powerpc/kernel/pci-hotplug.c b/arch/powerpc/kernel/pci-hotplug.c
index 6f444d0822d8..133ce03fdd82 100644
--- a/arch/powerpc/kernel/pci-hotplug.c
+++ b/arch/powerpc/kernel/pci-hotplug.c
@@ -140,6 +140,7 @@ void pci_hp_add_devices(struct pci_bus *bus)
 	struct pci_dev *dev;
 	struct pci_controller *phb;
 	struct device_node *dn = pci_bus_to_OF_node(bus);
+	int ret = 0;
 
 	if (!dn)
 		return;
@@ -176,6 +177,8 @@ void pci_hp_add_devices(struct pci_bus *bus)
 		for_each_pci_bridge(dev, bus)
 			max = pci_scan_bridge(bus, dev, max, 1);
 	}
-	pcibios_finish_adding_to_bus(bus);
+	ret = pcibios_finish_adding_to_bus(bus);
+	if (ret)
+		pr_err("Unable to add hotplug pci device!\n");
 }
 EXPORT_SYMBOL_GPL(pci_hp_add_devices);
diff --git a/arch/powerpc/platforms/pseries/pci_dlpar.c b/arch/powerpc/platforms/pseries/pci_dlpar.c
index 8c77ec7980de..2b78faba40f6 100644
--- a/arch/powerpc/platforms/pseries/pci_dlpar.c
+++ b/arch/powerpc/platforms/pseries/pci_dlpar.c
@@ -58,7 +58,8 @@ struct pci_controller *init_phb_dynamic(struct device_node *dn)
 		pseries_eeh_init_edev_recursive(PCI_DN(dn));
 
 	pcibios_scan_phb(phb);
-	pcibios_finish_adding_to_bus(phb->bus);
+	if (pcibios_finish_adding_to_bus(phb->bus))
+		return NULL;
 
 	return phb;
 }
diff --git a/drivers/pci/hotplug/rpadlpar_core.c b/drivers/pci/hotplug/rpadlpar_core.c
index 980bb3afd092..4c507dd04fa1 100644
--- a/drivers/pci/hotplug/rpadlpar_core.c
+++ b/drivers/pci/hotplug/rpadlpar_core.c
@@ -240,8 +240,10 @@ static int dlpar_add_phb(char *drc_name, struct device_node *dn)
 	}
 
 	phb = init_phb_dynamic(dn);
-	if (!phb)
+	if (!phb) {
+		pr_err("Unable to add hotplug slot %s\n", drc_name);
 		return -EIO;
+	}
 
 	if (rpaphp_add_slot(dn)) {
 		printk(KERN_ERR "%s: unable to add hotplug slot %s\n",
@@ -311,6 +313,9 @@ int dlpar_add_slot(char *drc_name)
 	}
 	of_node_put(dn);
 
+	if (rc)
+		goto exit;
+
 	printk(KERN_INFO "%s: slot %s added\n", DLPAR_MODULE_NAME, drc_name);
 exit:
 	mutex_unlock(&rpadlpar_mutex);
-- 
2.47.3