>From 067ec31ba1cb52c78c24196d5dea5ab0cb86dd9b Mon Sep 17 00:00:00 2001
From: Gu Zheng <guz.fnst@xxxxxxxxxxxxxx>
Date: Thu, 18 Apr 2013 16:51:48 +0900
Subject: [PATCH 1/3] PCI: take a reference on the bus object when we capture the struct pci_bus pointer
Take a reference on the bus object when we alloc a pci device on a target pci bus, in order to keep
the pci bus valid during the lifetime of devices downstream from it. And introduce pci_bus_get()/pci_bus_put()
to hide pci_bus' reference management.
Signed-off-by: Gu Zheng <guz.fnst@xxxxxxxxxxxxxx>
Reviewed-by: Tang Chen <tangchen@xxxxxxxxxxxxxx>
Reviewed-by: Li Guang <lig.fnst@xxxxxxxxxxxxxx>
---
arch/powerpc/kernel/pci_of_scan.c | 2 +-
drivers/pci/bus.c | 14 ++++++++++++++
drivers/pci/iov.c | 4 +++-
drivers/pci/probe.c | 2 +-
include/linux/pci.h | 3 +++
5 files changed, 22 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/kernel/pci_of_scan.c b/arch/powerpc/kernel/pci_of_scan.c
index 2a67e9b..9e0f6fd 100644
--- a/arch/powerpc/kernel/pci_of_scan.c
+++ b/arch/powerpc/kernel/pci_of_scan.c
@@ -137,7 +137,7 @@ struct pci_dev *of_create_pci_dev(struct device_node *node,
pr_debug(" create device, devfn: %x, type: %s\n", devfn, type);
- dev->bus = bus;
+ dev->bus = pci_bus_get(bus);
dev->dev.of_node = of_node_get(node);
dev->dev.parent = bus->bridge;
dev->dev.bus = &pci_bus_type;
diff --git a/drivers/pci/bus.c b/drivers/pci/bus.c
index 8647dc6..8e812bb 100644
--- a/drivers/pci/bus.c
+++ b/drivers/pci/bus.c
@@ -17,6 +17,20 @@
#include <linux/slab.h>
#include "pci.h"
+struct pci_bus *pci_bus_get(struct pci_bus *bus)
+{
+ if (bus)
+ get_device(&bus->dev);
+ return bus;
+}
+EXPORT_SYMBOL(pci_bus_get);
+
+void pci_bus_put(struct pci_bus *bus)
+{
+ if (bus)
+ put_device(&bus->dev);
+}
+EXPORT_SYMBOL(pci_bus_put);
void pci_add_resource_offset(struct list_head *resources, struct resource *res,
resource_size_t offset)
diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
index ee599f2..18798a7 100644
--- a/drivers/pci/iov.c
+++ b/drivers/pci/iov.c
@@ -73,6 +73,7 @@ static int virtfn_add(struct pci_dev *dev, int id, int reset)
u64 size;
char buf[VIRTFN_ID_LEN];
struct pci_dev *virtfn;
+ struct pci_bus *bus;
struct resource *res;
struct pci_sriov *iov = dev->sriov;
@@ -81,7 +82,8 @@ static int virtfn_add(struct pci_dev *dev, int id, int reset)
return -ENOMEM;
mutex_lock(&iov->dev->sriov->lock);
- virtfn->bus = virtfn_add_bus(dev->bus, virtfn_bus(dev, id));
+ bus = virtfn_add_bus(dev->bus, virtfn_bus(dev, id));
+ virtfn->bus = pci_bus_get(bus);
if (!virtfn->bus) {
kfree(virtfn);
mutex_unlock(&iov->dev->sriov->lock);
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index b494066..44a6f7d 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1265,7 +1265,7 @@ static struct pci_dev *pci_scan_device(struct pci_bus *bus, int devfn)
if (!dev)
return NULL;
- dev->bus = bus;
+ dev->bus = pci_bus_get(bus);
dev->devfn = devfn;
dev->vendor = l & 0xffff;
dev->device = (l >> 16) & 0xffff;
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 710067f..c4d064d 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1000,6 +1000,9 @@ int pci_request_selected_regions_exclusive(struct pci_dev *, int, const char *);
void pci_release_selected_regions(struct pci_dev *, int);
/* drivers/pci/bus.c */
+extern struct pci_bus *pci_bus_get(struct pci_bus *);
+extern void pci_bus_put(struct pci_bus *);
+
void pci_add_resource(struct list_head *resources, struct resource *res);
void pci_add_resource_offset(struct list_head *resources, struct resource *res,
resource_size_t offset);
--
1.7.1
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