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x86/PCI: use RCU list to protect mmconfig list

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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>
This commit is contained in:
Jiang Liu 2012-06-22 14:55:12 +08:00 committed by Bjorn Helgaas
parent 846e402300
commit 376f70acfe
3 changed files with 34 additions and 10 deletions
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18
arch/x86/pci/mmconfig-shared.c
View File

@ -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 @@ static __init void free_all_mmcfg(void)
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 @@ static __init struct pci_mmcfg_region *pci_mmconfig_add(int segment, int start,
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 *pci_mmconfig_lookup(int segment, int bus)
{
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;

13
arch/x86/pci/mmconfig_32.c
View File

@ -11,6 +11,7 @@
#include <linux/pci.h>
#include <linux/init.h>
#include <linux/rcupdate.h>
#include <asm/e820.h>
#include <asm/pci_x86.h>
#include <acpi/acpi.h>
@ -60,9 +61,12 @@ err: *value = -1;
return -EINVAL;
}
rcu_read_lock();
base = get_base_addr(seg, bus, devfn);
if (!base)
if (!base) {
rcu_read_unlock();
goto err;
}
raw_spin_lock_irqsave(&pci_config_lock, flags);
@ -80,6 +84,7 @@ err: *value = -1;
break;
}
raw_spin_unlock_irqrestore(&pci_config_lock, flags);
rcu_read_unlock();
return 0;
}
@ -93,9 +98,12 @@ static int pci_mmcfg_write(unsigned int seg, unsigned int bus,
if ((bus > 255) || (devfn > 255) || (reg > 4095))
return -EINVAL;
rcu_read_lock();
base = get_base_addr(seg, bus, devfn);
if (!base)
if (!base) {
rcu_read_unlock();
return -EINVAL;
}
raw_spin_lock_irqsave(&pci_config_lock, flags);
@ -113,6 +121,7 @@ static int pci_mmcfg_write(unsigned int seg, unsigned int bus,
break;
}
raw_spin_unlock_irqrestore(&pci_config_lock, flags);
rcu_read_unlock();
return 0;
}

13
arch/x86/pci/mmconfig_64.c
View File

@ -9,6 +9,7 @@
#include <linux/init.h>
#include <linux/acpi.h>
#include <linux/bitmap.h>
#include <linux/rcupdate.h>
#include <asm/e820.h>
#include <asm/pci_x86.h>
@ -34,9 +35,12 @@ err: *value = -1;
return -EINVAL;
}
rcu_read_lock();
addr = pci_dev_base(seg, bus, devfn);
if (!addr)
if (!addr) {
rcu_read_unlock();
goto err;
}
switch (len) {
case 1:
@ -49,6 +53,7 @@ err: *value = -1;
*value = mmio_config_readl(addr + reg);
break;
}
rcu_read_unlock();
return 0;
}
@ -62,9 +67,12 @@ static int pci_mmcfg_write(unsigned int seg, unsigned int bus,
if (unlikely((bus > 255) || (devfn > 255) || (reg > 4095)))
return -EINVAL;
rcu_read_lock();
addr = pci_dev_base(seg, bus, devfn);
if (!addr)
if (!addr) {
rcu_read_unlock();
return -EINVAL;
}
switch (len) {
case 1:
@ -77,6 +85,7 @@ static int pci_mmcfg_write(unsigned int seg, unsigned int bus,
mmio_config_writel(addr + reg, value);
break;
}
rcu_read_unlock();
return 0;
}