Add explicit locking to pci_hp_register/deregister. For a given pci_slot,
we want to make sure that the pci_slot->hotplug pointer isn't being
changed from underneath us.
Cc: jbarnes@xxxxxxxxxxxxxxxx
Cc: kristen.c.accardi@xxxxxxxxx
Cc: matthew@xxxxxx
Cc: kaneshige.kenji@xxxxxxxxxxxxxx
Signed-off-by: Alex Chiang <achiang@xxxxxx>
---
drivers/pci/hotplug/pci_hotplug_core.c | 7 +++++++
drivers/pci/slot.c | 4 ++--
2 files changed, 9 insertions(+), 2 deletions(-)
diff --git a/drivers/pci/hotplug/pci_hotplug_core.c b/drivers/pci/hotplug/pci_hotplug_core.c
index 0e7a511..e00266b 100644
--- a/drivers/pci/hotplug/pci_hotplug_core.c
+++ b/drivers/pci/hotplug/pci_hotplug_core.c
@@ -37,6 +37,7 @@
#include <linux/init.h>
#include <linux/mount.h>
#include <linux/namei.h>
+#include <linux/mutex.h>
#include <linux/pci.h>
#include <linux/pci_hotplug.h>
#include <asm/uaccess.h>
@@ -554,6 +555,7 @@ out:
*
* Returns 0 if successful, anything else for an error.
*/
+static DEFINE_MUTEX(pci_hp_mutex);
int pci_hp_register(struct hotplug_slot *slot, struct pci_bus *bus, int slot_nr,
const char *name)
{
@@ -583,7 +585,9 @@ int pci_hp_register(struct hotplug_slot *slot, struct pci_bus *bus, int slot_nr,
if (IS_ERR(pci_slot))
return PTR_ERR(pci_slot);
+ mutex_lock(&pci_hp_mutex);
if (pci_slot->hotplug) {
+ mutex_unlock(&pci_hp_mutex);
dbg("%s: already claimed\n", __func__);
pci_destroy_slot(pci_slot);
return -EBUSY;
@@ -591,6 +595,7 @@ int pci_hp_register(struct hotplug_slot *slot, struct pci_bus *bus, int slot_nr,
slot->pci_slot = pci_slot;
pci_slot->hotplug = slot;
+ mutex_unlock(&pci_hp_mutex);
/*
* Allow pcihp drivers to override the ACPI_PCI_SLOT name.
@@ -635,6 +640,7 @@ int pci_hp_deregister(struct hotplug_slot *hotplug)
if (temp != hotplug)
return -ENODEV;
+ mutex_lock(&pci_hp_mutex);
spin_lock(&pci_hotplug_slot_list_lock);
list_del(&hotplug->slot_list);
spin_unlock(&pci_hotplug_slot_list_lock);
@@ -645,6 +651,7 @@ int pci_hp_deregister(struct hotplug_slot *hotplug)
hotplug->release(hotplug);
slot->hotplug = NULL;
+ mutex_unlock(&pci_hp_mutex);
pci_destroy_slot(slot);
return 0;
diff --git a/drivers/pci/slot.c b/drivers/pci/slot.c
index 0c6db03..1fffb27 100644
--- a/drivers/pci/slot.c
+++ b/drivers/pci/slot.c
@@ -164,10 +164,10 @@ placeholder:
pr_debug("%s: created pci_slot on %04x:%02x:%02x\n",
__func__, pci_domain_nr(parent), parent->number, slot_nr);
- out:
+out:
up_write(&pci_bus_sem);
return slot;
- err:
+err:
kfree(slot);
slot = ERR_PTR(err);
goto out;
--
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