IB/hfi1: Fix "suspicious rcu_dereference_check() usage" warnings

This fixes the following warnings with PROVE_LOCKING and PROVE_RCU
enabled in the kernel:

case (1):
[ INFO: suspicious RCU usage. ]
drivers/infiniband/hw/hfi1/init.c:532
suspicious rcu_dereference_check() usage!

case (2):
[ INFO: suspicious RCU usage. ]
drivers/infiniband/hw/hfi1/hfi.h:1624
suspicious rcu_dereference_check() usage!

Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Jianxin Xiong <jianxin.xiong@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

1 files changed, 11 insertions, 2 deletions

diff --git a/drivers/infiniband/hw/hfi1/hfi.h b/drivers/infiniband/hw/hfi1/hfi.h
index 7df4cb2ed7da..d22876d0fdd3 100644
--- a/drivers/infiniband/hw/hfi1/hfi.h
+++ b/drivers/infiniband/hw/hfi1/hfi.h
@@ -1616,8 +1616,7 @@ static inline u16 hfi1_get_pkey(struct hfi1_ibport *ibp, unsigned index)
 }
 
 /*
- * Readers of cc_state must call get_cc_state() under rcu_read_lock().
- * Writers of cc_state must call get_cc_state() under cc_state_lock.
+ * Called by readers of cc_state only, must call under rcu_read_lock().
  */
 static inline struct cc_state *get_cc_state(struct hfi1_pportdata *ppd)
 {
@@ -1625,6 +1624,16 @@ static inline struct cc_state *get_cc_state(struct hfi1_pportdata *ppd)
 }
 
 /*
+ * Called by writers of cc_state only,  must call under cc_state_lock.
+ */
+static inline
+struct cc_state *get_cc_state_protected(struct hfi1_pportdata *ppd)
+{
+	return rcu_dereference_protected(ppd->cc_state,
+					 lockdep_is_held(&ppd->cc_state_lock));
+}
+
+/*
  * values for dd->flags (_device_ related flags)
  */
 #define HFI1_INITTED           0x1    /* chip and driver up and initted */