x86/PCI: use RCU list to protect mmconfig list
Use RCU list to protect mmconfig list from dynamic change
when supporting PCI host bridge hotplug.
Reviewed-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Jiang Liu <liuj97@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
diff --git a/arch/x86/pci/mmconfig-shared.c b/arch/x86/pci/mmconfig-shared.c
index 5e2cd2a..0ac97d5 100644
--- a/arch/x86/pci/mmconfig-shared.c
+++ b/arch/x86/pci/mmconfig-shared.c
@@ -17,6 +17,8 @@
#include <linux/bitmap.h>
#include <linux/dmi.h>
#include <linux/slab.h>
+#include <linux/mutex.h>
+#include <linux/rculist.h>
#include <asm/e820.h>
#include <asm/pci_x86.h>
#include <asm/acpi.h>
@@ -25,6 +27,7 @@
/* Indicate if the mmcfg resources have been placed into the resource table. */
static int __initdata pci_mmcfg_resources_inserted;
+static DEFINE_MUTEX(pci_mmcfg_lock);
LIST_HEAD(pci_mmcfg_list);
@@ -45,20 +48,20 @@
pci_mmconfig_remove(cfg);
}
-static __init void list_add_sorted(struct pci_mmcfg_region *new)
+static __devinit void list_add_sorted(struct pci_mmcfg_region *new)
{
struct pci_mmcfg_region *cfg;
/* keep list sorted by segment and starting bus number */
- list_for_each_entry(cfg, &pci_mmcfg_list, list) {
+ list_for_each_entry_rcu(cfg, &pci_mmcfg_list, list) {
if (cfg->segment > new->segment ||
(cfg->segment == new->segment &&
cfg->start_bus >= new->start_bus)) {
- list_add_tail(&new->list, &cfg->list);
+ list_add_tail_rcu(&new->list, &cfg->list);
return;
}
}
- list_add_tail(&new->list, &pci_mmcfg_list);
+ list_add_tail_rcu(&new->list, &pci_mmcfg_list);
}
static __devinit struct pci_mmcfg_region *pci_mmconfig_alloc(int segment,
@@ -101,8 +104,11 @@
struct pci_mmcfg_region *new;
new = pci_mmconfig_alloc(segment, start, end, addr);
- if (new)
+ if (new) {
+ mutex_lock(&pci_mmcfg_lock);
list_add_sorted(new);
+ mutex_unlock(&pci_mmcfg_lock);
+ }
return new;
}
@@ -111,7 +117,7 @@
{
struct pci_mmcfg_region *cfg;
- list_for_each_entry(cfg, &pci_mmcfg_list, list)
+ list_for_each_entry_rcu(cfg, &pci_mmcfg_list, list)
if (cfg->segment == segment &&
cfg->start_bus <= bus && bus <= cfg->end_bus)
return cfg;