Commit-ID: b41772abebc27c61dd578b76da99aa5240b4c99a
Gitweb: http://git.kernel.org/tip/b41772abebc27c61dd578b76da99aa5240b4c99a
Author: Paul E. McKenney <paul.mckenney@xxxxxxxxxx>
AuthorDate: Thu, 21 Jun 2012 20:50:42 -0700
Committer: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
CommitDate: Mon, 25 Jun 2012 12:35:25 -0700
rcu: Stop rcu_do_batch() from multiplexing the "count" variable
Commit b1420f1c (Make rcu_barrier() less disruptive) rearranged the
code in rcu_do_batch(), moving the ->qlen manipulation to follow
the requeueing of the callbacks. Unfortunately, this rearrangement
clobbered the value of the "count" local variable before the value
of rdp->qlen was adjusted, resulting in the value of rdp->qlen being
inaccurate. This commit therefore introduces an index variable "i",
avoiding the inadvertent multiplexing.
Signed-off-by: Paul E. McKenney <paul.mckenney@xxxxxxxxxx>
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Josh Triplett <josh@xxxxxxxxxxxxxxxx>
---
kernel/rcutree.c | 14 +++++++-------
1 files changed, 7 insertions(+), 7 deletions(-)
diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index 3b0f133..38ecdda 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -1530,7 +1530,7 @@ static void rcu_do_batch(struct rcu_state *rsp, struct rcu_data *rdp)
{
unsigned long flags;
struct rcu_head *next, *list, **tail;
- int bl, count, count_lazy;
+ int bl, count, count_lazy, i;
/* If no callbacks are ready, just return.*/
if (!cpu_has_callbacks_ready_to_invoke(rdp)) {
@@ -1553,9 +1553,9 @@ static void rcu_do_batch(struct rcu_state *rsp, struct rcu_data *rdp)
rdp->nxtlist = *rdp->nxttail[RCU_DONE_TAIL];
*rdp->nxttail[RCU_DONE_TAIL] = NULL;
tail = rdp->nxttail[RCU_DONE_TAIL];
- for (count = RCU_NEXT_SIZE - 1; count >= 0; count--)
- if (rdp->nxttail[count] == rdp->nxttail[RCU_DONE_TAIL])
- rdp->nxttail[count] = &rdp->nxtlist;
+ for (i = RCU_NEXT_SIZE - 1; i >= 0; i--)
+ if (rdp->nxttail[i] == rdp->nxttail[RCU_DONE_TAIL])
+ rdp->nxttail[i] = &rdp->nxtlist;
local_irq_restore(flags);
/* Invoke callbacks. */
@@ -1583,9 +1583,9 @@ static void rcu_do_batch(struct rcu_state *rsp, struct rcu_data *rdp)
if (list != NULL) {
*tail = rdp->nxtlist;
rdp->nxtlist = list;
- for (count = 0; count < RCU_NEXT_SIZE; count++)
- if (&rdp->nxtlist == rdp->nxttail[count])
- rdp->nxttail[count] = tail;
+ for (i = 0; i < RCU_NEXT_SIZE; i++)
+ if (&rdp->nxtlist == rdp->nxttail[i])
+ rdp->nxttail[i] = tail;
else
break;
}
--
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