| Message ID | 20120622153738.GA6800@linux.vnet.ibm.com |
|---|---|
| State | Accepted |
| Commit | b41772abebc27c61dd578b76da99aa5240b4c99a |
| Headers | show |
On Fri, Jun 22, 2012 at 08:37:38AM -0700, Paul E. McKenney wrote: > 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@linaro.org> > Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org> > diff --git a/kernel/rcutree.c b/kernel/rcutree.c > index 2f34d02..2001d38 100644 > --- a/kernel/rcutree.c > +++ b/kernel/rcutree.c > @@ -1593,7 +1593,7 @@ 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)) { > @@ -1616,9 +1616,9 @@ 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. */ > @@ -1646,9 +1646,9 @@ 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; > } >
diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 2f34d02..2001d38 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -1593,7 +1593,7 @@ 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)) { @@ -1616,9 +1616,9 @@ 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. */ @@ -1646,9 +1646,9 @@ 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; }