[PATCH] PCI: endpoint: Use blocking notifier instead of atomic

[Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>]

The use of atomic notifier causes sleeping in atomic context bug when
the EPC core functions are used in the notifier chain. This is due to the
use of epc->lock (mutex) in core functions protecting the concurrent use of
EPC.

So switch to blocking notifier for getting rid of the bug as it runs in
non-atomic context and allows sleeping in notifier chain.

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
---
 drivers/pci/endpoint/pci-epc-core.c | 10 +++++-----
 include/linux/pci-epc.h             |  6 +++---
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
index 6120d99bff73..6ad9b38b63a9 100644
--- a/drivers/pci/endpoint/pci-epc-core.c
+++ b/drivers/pci/endpoint/pci-epc-core.c
@@ -693,7 +693,7 @@ void pci_epc_linkup(struct pci_epc *epc)
 	if (!epc || IS_ERR(epc))
 		return;
 
-	atomic_notifier_call_chain(&epc->notifier, LINK_UP, NULL);
+	blocking_notifier_call_chain(&epc->notifier, LINK_UP, NULL);
 }
 EXPORT_SYMBOL_GPL(pci_epc_linkup);
 
@@ -710,7 +710,7 @@ void pci_epc_linkdown(struct pci_epc *epc)
 	if (!epc || IS_ERR(epc))
 		return;
 
-	atomic_notifier_call_chain(&epc->notifier, LINK_DOWN, NULL);
+	blocking_notifier_call_chain(&epc->notifier, LINK_DOWN, NULL);
 }
 EXPORT_SYMBOL_GPL(pci_epc_linkdown);
 
@@ -727,7 +727,7 @@ void pci_epc_init_notify(struct pci_epc *epc)
 	if (!epc || IS_ERR(epc))
 		return;
 
-	atomic_notifier_call_chain(&epc->notifier, CORE_INIT, NULL);
+	blocking_notifier_call_chain(&epc->notifier, CORE_INIT, NULL);
 }
 EXPORT_SYMBOL_GPL(pci_epc_init_notify);
 
@@ -744,7 +744,7 @@ void pci_epc_bme_notify(struct pci_epc *epc)
 	if (!epc || IS_ERR(epc))
 		return;
 
-	atomic_notifier_call_chain(&epc->notifier, BME, NULL);
+	blocking_notifier_call_chain(&epc->notifier, BME, NULL);
 }
 EXPORT_SYMBOL_GPL(pci_epc_bme_notify);
 
@@ -808,7 +808,7 @@ __pci_epc_create(struct device *dev, const struct pci_epc_ops *ops,
 
 	mutex_init(&epc->lock);
 	INIT_LIST_HEAD(&epc->pci_epf);
-	ATOMIC_INIT_NOTIFIER_HEAD(&epc->notifier);
+	BLOCKING_INIT_NOTIFIER_HEAD(&epc->notifier);
 
 	device_initialize(&epc->dev);
 	epc->dev.class = pci_epc_class;
diff --git a/include/linux/pci-epc.h b/include/linux/pci-epc.h
index 8454610df4c3..7a5c7705f86f 100644
--- a/include/linux/pci-epc.h
+++ b/include/linux/pci-epc.h
@@ -149,7 +149,7 @@ struct pci_epc {
 	/* mutex to protect against concurrent access of EP controller */
 	struct mutex			lock;
 	unsigned long			function_num_map;
-	struct atomic_notifier_head	notifier;
+	struct blocking_notifier_head	notifier;
 };
 
 /**
@@ -195,13 +195,13 @@ static inline void *epc_get_drvdata(struct pci_epc *epc)
 static inline int
 pci_epc_register_notifier(struct pci_epc *epc, struct notifier_block *nb)
 {
-	return atomic_notifier_chain_register(&epc->notifier, nb);
+	return blocking_notifier_chain_register(&epc->notifier, nb);
 }
 
 static inline int
 pci_epc_unregister_notifier(struct pci_epc *epc, struct notifier_block *nb)
 {
-	return atomic_notifier_chain_unregister(&epc->notifier, nb);
+	return blocking_notifier_chain_unregister(&epc->notifier, nb);
 }
 
 struct pci_epc *
-- 
2.25.1