From 8adf71fa145e5e309a07c1cca843da8cd83c1d75 Mon Sep 17 00:00:00 2001 From: Jianxin Xiong Date: Mon, 25 Jul 2016 13:39:14 -0700 Subject: [PATCH] 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 Signed-off-by: Jianxin Xiong Signed-off-by: Dennis Dalessandro Signed-off-by: Doug Ledford --- drivers/infiniband/hw/hfi1/hfi.h | 13 +++++++++++-- drivers/infiniband/hw/hfi1/init.c | 11 ++++++----- drivers/infiniband/hw/hfi1/mad.c | 2 +- 3 files changed, 18 insertions(+), 8 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 @@ -1616,14 +1616,23 @@ 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) { return rcu_dereference(ppd->cc_state); } +/* + * 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) */ diff --git a/drivers/infiniband/hw/hfi1/init.c b/drivers/infiniband/hw/hfi1/init.c index ec77c7edb025..44ec3a838b1b 100644 --- a/drivers/infiniband/hw/hfi1/init.c +++ b/drivers/infiniband/hw/hfi1/init.c @@ -475,8 +475,9 @@ static enum hrtimer_restart cca_timer_fn(struct hrtimer *t) void hfi1_init_pportdata(struct pci_dev *pdev, struct hfi1_pportdata *ppd, struct hfi1_devdata *dd, u8 hw_pidx, u8 port) { - int i, size; + int i; uint default_pkey_idx; + struct cc_state *cc_state; ppd->dd = dd; ppd->hw_pidx = hw_pidx; @@ -527,9 +528,9 @@ void hfi1_init_pportdata(struct pci_dev *pdev, struct hfi1_pportdata *ppd, spin_lock_init(&ppd->cc_state_lock); spin_lock_init(&ppd->cc_log_lock); - size = sizeof(struct cc_state); - RCU_INIT_POINTER(ppd->cc_state, kzalloc(size, GFP_KERNEL)); - if (!rcu_dereference(ppd->cc_state)) + cc_state = kzalloc(sizeof(*cc_state), GFP_KERNEL); + RCU_INIT_POINTER(ppd->cc_state, cc_state); + if (!cc_state) goto bail; return; @@ -1327,7 +1328,7 @@ static void cleanup_device_data(struct hfi1_devdata *dd) hrtimer_cancel(&ppd->cca_timer[i].hrtimer); spin_lock(&ppd->cc_state_lock); - cc_state = get_cc_state(ppd); + cc_state = get_cc_state_protected(ppd); RCU_INIT_POINTER(ppd->cc_state, NULL); spin_unlock(&ppd->cc_state_lock); diff --git a/drivers/infiniband/hw/hfi1/mad.c b/drivers/infiniband/hw/hfi1/mad.c index 5590a4c84a4e..1263abe01999 100644 --- a/drivers/infiniband/hw/hfi1/mad.c +++ b/drivers/infiniband/hw/hfi1/mad.c @@ -3375,7 +3375,7 @@ static void apply_cc_state(struct hfi1_pportdata *ppd) */ spin_lock(&ppd->cc_state_lock); - old_cc_state = get_cc_state(ppd); + old_cc_state = get_cc_state_protected(ppd); if (!old_cc_state) { /* never active, or shutting down */ spin_unlock(&ppd->cc_state_lock); -- 2.45.2