[PATCH v2 4/4] PCI/AER: fix a small race condition window when rmmod aer_inject

[Yijing Wang <wangyijing@huawei.com>]

Fix a small race condition window between pci_bus_ops_pop() and
pci_bus_set_ops() functions.

Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
---
 drivers/pci/pcie/aer/aer_inject.c |    8 ++------
 1 files changed, 2 insertions(+), 6 deletions(-)

diff --git a/drivers/pci/pcie/aer/aer_inject.c b/drivers/pci/pcie/aer/aer_inject.c
index bd043db..69c2d77 100644
--- a/drivers/pci/pcie/aer/aer_inject.c
+++ b/drivers/pci/pcie/aer/aer_inject.c
@@ -141,12 +141,11 @@ static struct pci_ops *__find_pci_bus_ops(struct pci_bus *bus)
 	return NULL;
 }
 
+/* inject_lock must be held before calling */
 static struct pci_bus_ops *pci_bus_ops_pop(void)
 {
-	unsigned long flags;
 	struct pci_bus_ops *bus_ops = NULL;
 
-	spin_lock_irqsave(&inject_lock, flags);
 	if (list_empty(&pci_bus_ops_list))
 		bus_ops = NULL;
 	else {
@@ -154,7 +153,6 @@ static struct pci_bus_ops *pci_bus_ops_pop(void)
 		list_del(lh);
 		bus_ops = list_entry(lh, struct pci_bus_ops, list);
 	}
-	spin_unlock_irqrestore(&inject_lock, flags);
 	return bus_ops;
 }
 
@@ -610,14 +608,12 @@ static void __exit aer_inject_exit(void)
 	bus_unregister_notifier(&pci_bus_type, &aerinj_hp_notifier);
 	misc_deregister(&aer_inject_device);
 
+	spin_lock_irqsave(&inject_lock, flags);
 	while ((bus_ops = pci_bus_ops_pop())) {
 		pci_bus_set_ops(bus_ops->bus, bus_ops->ops);
 		kfree(bus_ops);
 	}
 	
-	clean_untracked_pci_aer_ops();
-
-	spin_lock_irqsave(&inject_lock, flags);
 	list_for_each_entry_safe(err, err_next, &einjected, list) {
 		list_del(&err->list);
 		kfree(err);
-- 
1.7.1