@@ -78,6 +78,7 @@ struct slot {
struct hotplug_slot *hotplug_slot;
struct delayed_work work; /* work for button event */
struct mutex lock;
+ struct mutex hotplug_lock;
struct workqueue_struct *wq;
};
@@ -281,8 +281,11 @@ static int pciehp_probe(struct pcie_device *dev)
slot = ctrl->slot;
pciehp_get_adapter_status(slot, &occupied);
pciehp_get_power_status(slot, &poweron);
- if (occupied && pciehp_force)
+ if (occupied && pciehp_force) {
+ mutex_lock(&slot->hotplug_lock);
pciehp_enable_slot(slot);
+ mutex_unlock(&slot->hotplug_lock);
+ }
/* If empty slot's power status is on, turn power off */
if (!occupied && poweron && POWER_CTRL(ctrl))
pciehp_power_off_slot(slot);
@@ -326,10 +329,12 @@ static int pciehp_resume (struct pcie_device *dev)
/* Check if slot is occupied */
pciehp_get_adapter_status(slot, &status);
+ mutex_lock(&slot->hotplug_lock);
if (status)
pciehp_enable_slot(slot);
else
pciehp_disable_slot(slot);
+ mutex_unlock(&slot->hotplug_lock);
return 0;
}
#endif /* PM */
@@ -316,6 +316,7 @@ static void pciehp_power_thread(struct work_struct *work)
struct power_work_info *info =
container_of(work, struct power_work_info, work);
struct slot *p_slot = info->p_slot;
+ int ret;
switch (info->req) {
case DISABLE_REQ:
@@ -323,7 +324,9 @@ static void pciehp_power_thread(struct work_struct *work)
"Disabling domain:bus:device=%04x:%02x:00\n",
pci_domain_nr(p_slot->ctrl->pcie->port->subordinate),
p_slot->ctrl->pcie->port->subordinate->number);
+ mutex_lock(&p_slot->hotplug_lock);
pciehp_disable_slot(p_slot);
+ mutex_unlock(&p_slot->hotplug_lock);
mutex_lock(&p_slot->lock);
p_slot->state = STATIC_STATE;
mutex_unlock(&p_slot->lock);
@@ -333,7 +336,10 @@ static void pciehp_power_thread(struct work_struct *work)
"Enabling domain:bus:device=%04x:%02x:00\n",
pci_domain_nr(p_slot->ctrl->pcie->port->subordinate),
p_slot->ctrl->pcie->port->subordinate->number);
- if (pciehp_enable_slot(p_slot) && PWR_LED(p_slot->ctrl))
+ mutex_lock(&p_slot->hotplug_lock);
+ ret = pciehp_enable_slot(p_slot);
+ mutex_unlock(&p_slot->hotplug_lock);
+ if (ret && PWR_LED(p_slot->ctrl))
pciehp_green_led_off(p_slot);
mutex_lock(&p_slot->lock);
p_slot->state = STATIC_STATE;
@@ -613,6 +619,9 @@ static void interrupt_event_handler(struct work_struct *work)
kfree(info);
}
+/*
+ * Note: This function must be called with slot->hotplug_lock held
+ */
int pciehp_enable_slot(struct slot *p_slot)
{
u8 getstatus = 0;
@@ -651,7 +660,9 @@ int pciehp_enable_slot(struct slot *p_slot)
return rc;
}
-
+/*
+ * Note: This function must be called with slot->hotplug_lock held
+ */
int pciehp_disable_slot(struct slot *p_slot)
{
u8 getstatus = 0;
@@ -710,7 +721,9 @@ int pciehp_sysfs_enable_slot(struct slot *p_slot)
case STATIC_STATE:
p_slot->state = POWERON_STATE;
mutex_unlock(&p_slot->lock);
+ mutex_lock(&p_slot->hotplug_lock);
retval = pciehp_enable_slot(p_slot);
+ mutex_unlock(&p_slot->hotplug_lock);
mutex_lock(&p_slot->lock);
p_slot->state = STATIC_STATE;
break;
@@ -841,6 +841,7 @@ static int pcie_init_slot(struct controller *ctrl)
slot->ctrl = ctrl;
mutex_init(&slot->lock);
+ mutex_init(&slot->hotplug_lock);
INIT_DELAYED_WORK(&slot->work, pciehp_queue_pushbutton_work);
ctrl->slot = slot;
return 0;
Today it is there is no protection around pciehp_enable_slot() and pciehp_disable_slot() to ensure that they complete before another hot-plug operation can be done on that particular slot. This patch introduces the slot->hotplug_lock to ensure that any hotplug operations (add / remove) complete before another HP event can begin processing on that particular slot. Signed-off-by: Rajat Jain <rajatjain@juniper.net> --- The problem we are trying to solve is that it should not be the case that the PCI tree is left in an unpredictable or bad state because pciehp_disable_slot() may get to execute before pciehp_enable_slot() completes its execution. I'm not 100% confident that this particular patch is needed. If some one can confirm me, that the problem this patch is trying to solve, does not exist, I'll be happy to do away without this patch. drivers/pci/hotplug/pciehp.h | 1 + drivers/pci/hotplug/pciehp_core.c | 7 ++++++- drivers/pci/hotplug/pciehp_ctrl.c | 17 +++++++++++++++-- drivers/pci/hotplug/pciehp_hpc.c | 1 + 4 files changed, 23 insertions(+), 3 deletions(-)