When I use the following command to power on a slot which has been
powered off already.
echo 1 > /sys/bus/pci/slots/22/power
It prints the following error:
-bash: echo: write error: No such device
But the slot is actually powered on and the devices is probed.
In function 'pciehp_sysfs_enable_slot()', we use 'wait_event()' to wait
until 'ctrl->pending_events' is cleared in 'pciehp_ist()'. But in some
situation, when 'pciehp_ist()' is woken up on a nearby CPU after
'pciehp_request' is called, 'ctrl->pending_events' is cleared before we
go into sleep state. 'wait_event()' will check the condition before
going into sleep. So we return immediately and '-ENODEV' is return.
This patch use struct completion to wait until irq_thread 'pciehp_ist'
is completed.
Signed-off-by: Xiongfeng Wang <wangxiongfeng2@xxxxxxxxxx>
---
drivers/pci/hotplug/pciehp.h | 2 +-
drivers/pci/hotplug/pciehp_ctrl.c | 8 ++++----
drivers/pci/hotplug/pciehp_hpc.c | 4 ++--
3 files changed, 7 insertions(+), 7 deletions(-)
diff --git a/drivers/pci/hotplug/pciehp.h b/drivers/pci/hotplug/pciehp.h
index 8c51a04..f8c3826 100644
--- a/drivers/pci/hotplug/pciehp.h
+++ b/drivers/pci/hotplug/pciehp.h
@@ -102,7 +102,7 @@ struct controller {
struct hotplug_slot hotplug_slot; /* hotplug core interface */
struct rw_semaphore reset_lock;
int request_result;
- wait_queue_head_t requester;
+ struct completion requester;
};
/**
diff --git a/drivers/pci/hotplug/pciehp_ctrl.c b/drivers/pci/hotplug/pciehp_ctrl.c
index 631ced0..2237793 100644
--- a/drivers/pci/hotplug/pciehp_ctrl.c
+++ b/drivers/pci/hotplug/pciehp_ctrl.c
@@ -366,9 +366,9 @@ int pciehp_sysfs_enable_slot(struct hotplug_slot *hotplug_slot)
* card before the thread wakes up, so initialize to -ENODEV.
*/
ctrl->request_result = -ENODEV;
+ reinit_completion(&ctrl->requester);
pciehp_request(ctrl, PCI_EXP_SLTSTA_PDC);
- wait_event(ctrl->requester,
- !atomic_read(&ctrl->pending_events));
+ wait_for_completion(&ctrl->requester);
return ctrl->request_result;
case POWERON_STATE:
ctrl_info(ctrl, "Slot(%s): Already in powering on state\n",
@@ -399,9 +399,9 @@ int pciehp_sysfs_disable_slot(struct hotplug_slot *hotplug_slot)
case BLINKINGOFF_STATE:
case ON_STATE:
mutex_unlock(&ctrl->state_lock);
+ reinit_completion(&ctrl->requester);
pciehp_request(ctrl, DISABLE_SLOT);
- wait_event(ctrl->requester,
- !atomic_read(&ctrl->pending_events));
+ wait_for_completion(&ctrl->requester);
return ctrl->request_result;
case POWEROFF_STATE:
ctrl_info(ctrl, "Slot(%s): Already in powering off state\n",
diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c
index bd990e3..0a74b48 100644
--- a/drivers/pci/hotplug/pciehp_hpc.c
+++ b/drivers/pci/hotplug/pciehp_hpc.c
@@ -654,7 +654,7 @@ static irqreturn_t pciehp_ist(int irq, void *dev_id)
up_read(&ctrl->reset_lock);
pci_config_pm_runtime_put(pdev);
- wake_up(&ctrl->requester);
+ complete(&ctrl->requester);
return IRQ_HANDLED;
}
@@ -862,7 +862,7 @@ struct controller *pcie_init(struct pcie_device *dev)
mutex_init(&ctrl->ctrl_lock);
mutex_init(&ctrl->state_lock);
init_rwsem(&ctrl->reset_lock);
- init_waitqueue_head(&ctrl->requester);
+ init_completion(&ctrl->requester);
init_waitqueue_head(&ctrl->queue);
INIT_DELAYED_WORK(&ctrl->button_work, pciehp_queue_pushbutton_work);
dbg_ctrl(ctrl);
--
1.7.12.4
