Signed-off-by: Jiang Liu<jiang.liu@xxxxxxxxxx>
---
drivers/pci/bus.c | 20 ++++++-
drivers/pci/probe.c | 5 +-
drivers/pci/remove.c | 5 +-
drivers/pci/search.c | 165 ++++++++++++++++++++++++++++++++++++++++++--------
include/linux/pci.h | 8 +++
5 files changed, 173 insertions(+), 30 deletions(-)
diff --git a/drivers/pci/bus.c b/drivers/pci/bus.c
index 1eb7944..0543d47 100644
--- a/drivers/pci/bus.c
+++ b/drivers/pci/bus.c
@@ -15,6 +15,7 @@
#include<linux/proc_fs.h>
#include<linux/init.h>
#include<linux/slab.h>
+#include<linux/rculist.h>
#include "pci.h"
@@ -238,7 +239,7 @@ void pci_bus_add_devices(const struct pci_bus *bus)
continue;
if (list_empty(&child->node)) {
down_write(&pci_bus_sem);
- list_add_tail(&child->node,&dev->bus->children);
+ list_add_tail_rcu(&child->node,&dev->bus->children);
up_write(&pci_bus_sem);
}
pci_bus_add_devices(child);
@@ -277,7 +278,7 @@ void pci_bus_add_single_device(struct pci_dev *dev)
if (child) {
if (list_empty(&child->node)) {
down_write(&pci_bus_sem);
- list_add_tail(&child->node,&dev->bus->children);
+ list_add_tail_rcu(&child->node,&dev->bus->children);
up_write(&pci_bus_sem);
}
pci_bus_add_devices(child);
@@ -364,6 +365,21 @@ void pci_walk_bus(struct pci_bus *top, int (*cb)(struct pci_dev *, void *),
}
EXPORT_SYMBOL_GPL(pci_walk_bus);
+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);
+
EXPORT_SYMBOL(pci_bus_alloc_resource);
EXPORT_SYMBOL_GPL(pci_bus_add_device);
EXPORT_SYMBOL(pci_bus_add_devices);
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 0ca213c..273c387 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -10,6 +10,7 @@
#include<linux/module.h>
#include<linux/cpumask.h>
#include<linux/pci-aspm.h>
+#include<linux/rculist.h>
#include "pci.h"
#define CARDBUS_LATENCY_TIMER 176 /* secondary latency timer */
@@ -633,7 +634,7 @@ struct pci_bus *__ref pci_add_new_bus(struct pci_bus *parent, struct pci_dev *de
child = pci_alloc_child_bus(parent, dev, busnr);
if (child) {
down_write(&pci_bus_sem);
- list_add_tail(&child->node,&parent->children);
+ list_add_tail_rcu(&child->node,&parent->children);
up_write(&pci_bus_sem);
}
return child;
@@ -1889,7 +1890,7 @@ struct pci_bus *pci_create_root_bus(struct device *parent, int bus,
}
down_write(&pci_bus_sem);
- list_add_tail(&b->node,&pci_root_buses);
+ list_add_tail_rcu(&b->node,&pci_root_buses);
up_write(&pci_bus_sem);
return b;
diff --git a/drivers/pci/remove.c b/drivers/pci/remove.c
index 25f368e..120bee9 100644
--- a/drivers/pci/remove.c
+++ b/drivers/pci/remove.c
@@ -1,6 +1,7 @@
#include<linux/pci.h>
#include<linux/module.h>
#include<linux/pci-aspm.h>
+#include<linux/rculist.h>
#include "pci.h"
static void pci_free_resources(struct pci_dev *dev)
@@ -67,9 +68,11 @@ void pci_remove_bus(struct pci_bus *pci_bus)
pci_proc_detach_bus(pci_bus);
down_write(&pci_bus_sem);
- list_del(&pci_bus->node);
+ list_del_rcu(&pci_bus->node);
pci_bus_release_busn_res(pci_bus);
up_write(&pci_bus_sem);
+ synchronize_rcu();
+
if (pci_bus->is_added || pci_is_root_bus(pci_bus)) {
pci_remove_legacy_files(pci_bus);
device_unregister(&pci_bus->dev);
diff --git a/drivers/pci/search.c b/drivers/pci/search.c
index b572730..de31957 100644
--- a/drivers/pci/search.c
+++ b/drivers/pci/search.c
@@ -12,6 +12,7 @@
#include<linux/slab.h>
#include<linux/module.h>
#include<linux/interrupt.h>
+#include<linux/rculist.h>
#include "pci.h"
DECLARE_RWSEM(pci_bus_sem);
@@ -52,20 +53,63 @@ pci_find_upstream_pcie_bridge(struct pci_dev *pdev)
static struct pci_bus *pci_do_find_bus(struct pci_bus *bus, unsigned char busnr)
{
- struct pci_bus* child;
- struct list_head *tmp;
+ struct pci_bus *child;
+ struct pci_bus *tmp_bus;
if(bus->number == busnr)
return bus;
- list_for_each(tmp,&bus->children) {
- child = pci_do_find_bus(pci_bus_b(tmp), busnr);
- if(child)
- return child;
+ list_for_each_entry_rcu(child,&bus->children, node) {
+ tmp_bus = pci_do_find_bus(child, busnr);
+ if(tmp_bus)
+ return tmp_bus;
}
return NULL;
}
+static struct pci_bus *__pci_find_bus(int domain, int busnr)
+{
+ struct pci_bus *bus;
+ struct pci_bus *tmp_bus;
+
+ list_for_each_entry_rcu(bus,&pci_root_buses, node) {
+ if (pci_domain_nr(bus) != domain)
+ continue;
+ tmp_bus = pci_do_find_bus(bus, busnr);
+ if (tmp_bus)
+ return tmp_bus;
+ }
+
+ return NULL;
+}
+
+static struct pci_bus *__pci_find_next_bus(const struct pci_bus *from)
+{
+ struct list_head *n;
+ struct pci_bus *b = NULL;
+
+ /* First search, start from the pci root bus list */
+ if (from == NULL) {
+ n = rcu_dereference(list_next_rcu(&pci_root_buses));
+ if (n !=&pci_root_buses)
+ b = pci_bus_b(n);
+ /* Continue on the pci root bus list */
+ } else if (pci_is_root_bus((struct pci_bus *)from)) {
+ n = rcu_dereference(list_next_rcu(&from->node));
+ if (n !=&pci_root_buses)
+ b = pci_bus_b(n);
+ /* Continue on other non pci root bus list */
+ } else {
+ struct pci_bus *parent = from->self->bus;
+
+ n = rcu_dereference(list_next_rcu(&from->node));
+ if (n !=&parent->children)
+ b = pci_bus_b(n);
+ }
+
+ return b;
+}
+
/**
* pci_find_bus - locate PCI bus from a given domain and bus number
* @domain: number of PCI domain to search
@@ -74,20 +118,19 @@ static struct pci_bus *pci_do_find_bus(struct pci_bus *bus, unsigned char busnr)
* Given a PCI bus number and domain number, the desired PCI bus is located
* in the global list of PCI buses. If the bus is found, a pointer to its
* data structure is returned. If no bus is found, %NULL is returned.
+ *
+ * TODO: By design, this function should only be called at boot time.
+ * So either mark it as __init or deprecate it.
*/
struct pci_bus * pci_find_bus(int domain, int busnr)
{
- struct pci_bus *bus = NULL;
- struct pci_bus *tmp_bus;
+ struct pci_bus *bus;
- while ((bus = pci_find_next_bus(bus)) != NULL) {
- if (pci_domain_nr(bus) != domain)
- continue;
- tmp_bus = pci_do_find_bus(bus, busnr);
- if (tmp_bus)
- return tmp_bus;
- }
- return NULL;
+ rcu_read_lock();
+ bus = __pci_find_bus(domain, busnr);
+ rcu_read_unlock();
+
+ return bus;
}
/**
@@ -98,21 +141,93 @@ struct pci_bus * pci_find_bus(int domain, int busnr)
* initiated by passing %NULL as the @from argument. Otherwise if
* @from is not %NULL, searches continue from next device on the
* global list.
+ *
+ * TODO: By design, this function should only be called at boot time.
+ * So either mark it as __init or deprecate it.
*/
struct pci_bus *
pci_find_next_bus(const struct pci_bus *from)
{
- struct list_head *n;
- struct pci_bus *b = NULL;
+ struct pci_bus *bus;
- WARN_ON(in_interrupt());
- down_read(&pci_bus_sem);
- n = from ? from->node.next : pci_root_buses.next;
- if (n !=&pci_root_buses)
- b = pci_bus_b(n);
- up_read(&pci_bus_sem);
- return b;
+ rcu_read_lock();
+ bus = __pci_find_next_bus(from);
+ rcu_read_unlock();
+
+ return bus;
+}
+
+/**
+ * pci_get_bus - locate PCI bus from a given domain and bus number
+ * @domain: number of PCI domain to search
+ * @busnr: number of desired PCI bus
+ *
+ * Given a PCI bus number and domain number, the desired PCI bus is located
+ * in the global list of PCI buses. If the bus is found, a pointer to its
+ * data structure is returned, and the reference count to the bus is increased.
+ * Otherwise, %NULL is returned.
+ */
+struct pci_bus *
+pci_get_bus(int domain, int busnr)
+{
+ struct pci_bus *bus;
+
+ rcu_read_lock();
+ bus = pci_bus_get(__pci_find_bus(domain, busnr));
+ rcu_read_unlock();
+
+ return bus;
+}
+EXPORT_SYMBOL(pci_get_bus);
+
+/**
+ * pci_get_next_bus - begin or continue searching for a PCI bus
+ * @from: Previous PCI bus found, or %NULL for new search.
+ *
+ * Iterates through the list of known PCI busses. A new search is
+ * initiated by passing %NULL as the @from argument. Otherwise if
+ * @from is not %NULL, searches continue from next device on the
+ * global list. If a bus is found, a pointer to its data structure
+ * is returned, and the reference count to the bus is increased.
+ * Otherwise, %NULL is returned.
+ * The reference count for @from is always decremented if it is not %NULL.
+ */
+struct pci_bus *
+pci_get_next_bus(struct pci_bus *from)
+{
+ struct pci_bus *bus;
+
+ rcu_read_lock();
+ bus = pci_bus_get(__pci_find_next_bus(from));
+ rcu_read_unlock();
+
+ return bus;
+}
+EXPORT_SYMBOL(pci_get_next_bus);
+
+/**
+ * pci_bus_present - Returns true if a bus with the (@domain, @busnr)
+ * is present, false if not.
+ * @domain: number of PCI domain to search
+ * @busnr: number of desired PCI bus
+ *
+ * Obvious fact: You do not have a reference to any bus that might be found
+ * by this function, so if that bus is removed from the system right after
+ * this function is finished, the value will be stale. Use this function to
+ * find buses that are usually built into a system, or for a general hint as
+ * to if another device happens to be present at this specific moment in time.
+ */
+bool pci_bus_present(int domain, int busnr)
+{
+ struct pci_bus *bus;
+
+ rcu_read_lock();
+ bus = __pci_find_bus(domain, busnr);
+ rcu_read_unlock();
+
+ return !!bus;
}
+EXPORT_SYMBOL(pci_bus_present);
/**
* pci_get_slot - locate PCI device for a given PCI slot
diff --git a/include/linux/pci.h b/include/linux/pci.h
index ec8c4cf..222bc88 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -731,6 +731,11 @@ int pci_find_ht_capability(struct pci_dev *dev, int ht_cap);
int pci_find_next_ht_capability(struct pci_dev *dev, int pos, int ht_cap);
struct pci_bus *pci_find_next_bus(const struct pci_bus *from);
+struct pci_bus *pci_bus_get(struct pci_bus *bus);
+void pci_bus_put(struct pci_bus *bus);
+struct pci_bus *pci_get_bus(int domain, int busnr);
+struct pci_bus *pci_get_next_bus(struct pci_bus *from);
+bool pci_bus_present(int domain, int busnr);
struct pci_dev *pci_get_device(unsigned int vendor, unsigned int device,
struct pci_dev *from);
struct pci_dev *pci_get_subsys(unsigned int vendor, unsigned int device,
@@ -1321,6 +1326,9 @@ static inline void pci_unblock_cfg_access(struct pci_dev *dev)
static inline struct pci_bus *pci_find_next_bus(const struct pci_bus *from)
{ return NULL; }
+static inline struct pci_bus *pci_get_next_bus(const struct pci_bus *from)
+{ return NULL; }
+
static inline struct pci_dev *pci_get_slot(struct pci_bus *bus,
unsigned int devfn)
{ return NULL; }
--
1.7.5.4
