* [PATCH] qib_qp: Replace rcu_assign_pointer() with RCU_INIT_POINTER()
@ 2014-08-18 12:42 Andreea-Cristina Bernat
2014-09-19 12:44 ` Marciniszyn, Mike
0 siblings, 1 reply; 2+ messages in thread
From: Andreea-Cristina Bernat @ 2014-08-18 12:42 UTC (permalink / raw)
To: infinipath, roland, sean.hefty, hal.rosenstock, linux-rdma, linux-kernel
Cc: paulmck
The uses of "rcu_assign_pointer()" are NULLing out the pointers.
According to RCU_INIT_POINTER()'s block comment:
"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.
The following Coccinelle semantic patch was used:
@@
@@
- rcu_assign_pointer
+ RCU_INIT_POINTER
(..., NULL)
Signed-off-by: Andreea-Cristina Bernat <bernat.ada@gmail.com>
---
drivers/infiniband/hw/qib/qib_qp.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/infiniband/hw/qib/qib_qp.c b/drivers/infiniband/hw/qib/qib_qp.c
index 7fcc150..17daf42 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;
@@ -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)))
--
1.9.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* RE: [PATCH] qib_qp: Replace rcu_assign_pointer() with RCU_INIT_POINTER()
2014-08-18 12:42 [PATCH] qib_qp: Replace rcu_assign_pointer() with RCU_INIT_POINTER() Andreea-Cristina Bernat
@ 2014-09-19 12:44 ` Marciniszyn, Mike
0 siblings, 0 replies; 2+ messages in thread
From: Marciniszyn, Mike @ 2014-09-19 12:44 UTC (permalink / raw)
To: Andreea-Cristina Bernat
Cc: paulmck, roland, Hefty, Sean, hal.rosenstock, linux-rdma, linux-kernel
> Subject: [PATCH] qib_qp: Replace rcu_assign_pointer() with
> RCU_INIT_POINTER()
>
I would prefer the summary line be:
IB/qib: remove_qp() use RCU_INIT_POINTER() instead of rcu_assign_pointer()
Otherwise I agree with the patch and I have tested it with large numbers of QPs.
Mike
^ permalink raw reply [flat|nested] 2+ messages in thread
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2014-08-18 12:42 [PATCH] qib_qp: Replace rcu_assign_pointer() with RCU_INIT_POINTER() Andreea-Cristina Bernat
2014-09-19 12:44 ` Marciniszyn, Mike
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