IB/qib: Replace rcu_assign_pointer() with RCU_INIT_POINTER() in qib_qp.c
Author: Andreea-Cristina Bernat <bernat.ada@gmail.com>
According to RCU_INIT_POINTER()'s block comment 3.a, it can be used if
"1. This use of RCU_INIT_POINTER() is NULLing out the pointer"
it is better to use it instead of rcu_assign_pointer() because it has a
smaller overhead.
"3. The referenced data structure has already been exposed to readers either
at compile time or via rcu_assign_pointer() -and-
a. You have not made -any- reader-visible changes to this structure since
then".
These cases fulfill the conditions above because between the
rcu_dereference_protected() call and the rcu_assign_pointer() call
there is no update of that value. Therefore, this patch makes the
replacement.
The following Coccinelle semantic patch was used:
@@
@@
- rcu_assign_pointer
+ RCU_INIT_POINTER
(...,
(
rtnl_dereference(...)
|
rcu_dereference_protected(...)
) )
[consolidated from http://marc.info/?l=linux-rdma&m=140836578119485&w=2 and
http://marc.info/?l=linux-rdma&m=140906361403047&w=2]
Tested-by: Mike Marciniszyn
Signed-off-by: Andreea-Cristina Bernat
Signed-off-by: Mike Marciniszyn
Signed-off-by: Roland Dreier
---
drivers/infiniband/hw/qib/qib_qp.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/infiniband/hw/qib/qib_qp.c b/drivers/infiniband/hw/qib/qib_qp.c
index 6ddc026..4fa88ba 100644
--- a/drivers/infiniband/hw/qib/qib_qp.c
+++ b/drivers/infiniband/hw/qib/qib_qp.c
@@ -255,10 +255,10 @@ static void remove_qp(struct qib_ibdev *dev, struct qib_qp *qp)
if (rcu_dereference_protected(ibp->qp0,
lockdep_is_held(&dev->qpt_lock)) == qp) {
- rcu_assign_pointer(ibp->qp0, NULL);
+ RCU_INIT_POINTER(ibp->qp0, NULL);
} else if (rcu_dereference_protected(ibp->qp1,
lockdep_is_held(&dev->qpt_lock)) == qp) {
- rcu_assign_pointer(ibp->qp1, NULL);
+ RCU_INIT_POINTER(ibp->qp1, NULL);
} else {
struct qib_qp *q;
struct qib_qp __rcu **qpp;
@@ -269,7 +269,7 @@ static void remove_qp(struct qib_ibdev *dev, struct qib_qp *qp)
lockdep_is_held(&dev->qpt_lock))) != NULL;
qpp = &q->next)
if (q == qp) {
- rcu_assign_pointer(*qpp,
+ RCU_INIT_POINTER(*qpp,
rcu_dereference_protected(qp->next,
lockdep_is_held(&dev->qpt_lock)));
removed = 1;
@@ -315,7 +315,7 @@ unsigned qib_free_all_qps(struct qib_devdata *dd)
for (n = 0; n < dev->qp_table_size; n++) {
qp = rcu_dereference_protected(dev->qp_table[n],
lockdep_is_held(&dev->qpt_lock));
- rcu_assign_pointer(dev->qp_table[n], NULL);
+ RCU_INIT_POINTER(dev->qp_table[n], NULL);
for (; qp; qp = rcu_dereference_protected(qp->next,
lockdep_is_held(&dev->qpt_lock))) |
---
drivers/infiniband/hw/qib/qib_qp.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/infiniband/hw/qib/qib_qp.c b/drivers/infiniband/hw/qib/qib_qp.c
index 6ddc026..4fa88ba 100644
--- a/drivers/infiniband/hw/qib/qib_qp.c
+++ b/drivers/infiniband/hw/qib/qib_qp.c
@@ -255,10 +255,10 @@ static void remove_qp(struct qib_ibdev *dev, struct qib_qp *qp)
if (rcu_dereference_protected(ibp->qp0,
lockdep_is_held(&dev->qpt_lock)) == qp) {
- rcu_assign_pointer(ibp->qp0, NULL);
+ RCU_INIT_POINTER(ibp->qp0, NULL);
} else if (rcu_dereference_protected(ibp->qp1,
lockdep_is_held(&dev->qpt_lock)) == qp) {
- rcu_assign_pointer(ibp->qp1, NULL);
+ RCU_INIT_POINTER(ibp->qp1, NULL);
} else {
struct qib_qp *q;
struct qib_qp __rcu **qpp;
@@ -269,7 +269,7 @@ static void remove_qp(struct qib_ibdev *dev, struct qib_qp *qp)
lockdep_is_held(&dev->qpt_lock))) != NULL;
qpp = &q->next)
if (q == qp) {
- rcu_assign_pointer(*qpp,
+ RCU_INIT_POINTER(*qpp,
rcu_dereference_protected(qp->next,
lockdep_is_held(&dev->qpt_lock)));
removed = 1;
@@ -315,7 +315,7 @@ unsigned qib_free_all_qps(struct qib_devdata *dd)
for (n = 0; n < dev->qp_table_size; n++) {
qp = rcu_dereference_protected(dev->qp_table[n],
lockdep_is_held(&dev->qpt_lock));
- rcu_assign_pointer(dev->qp_table[n], NULL);
+ RCU_INIT_POINTER(dev->qp_table[n], NULL);
for (; qp; qp = rcu_dereference_protected(qp->next,
lockdep_is_held(&dev->qpt_lock)))