Techwizz/kernel-fxtec-pro1x
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

rcu: Stop rcu_do_batch() from multiplexing the "count" variable

Browse source 
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>
This commit is contained in:
Paul E. McKenney 2012-06-21 20:50:42 -07:00 committed by Paul E. McKenney
parent 6b16351acb
commit b41772abeb
1 changed files with 7 additions and 7 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

14
kernel/rcutree.c
View file

@ -1530,7 +1530,7 @@ static void rcu_do_batch(struct rcu_state *rsp, struct rcu_data *rdp)
{ {
unsigned long flags; unsigned long flags;
struct rcu_head *next, *list, **tail; 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 no callbacks are ready, just return.*/
if (!cpu_has_callbacks_ready_to_invoke(rdp)) { 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->nxtlist = *rdp->nxttail[RCU_DONE_TAIL];
*rdp->nxttail[RCU_DONE_TAIL] = NULL; *rdp->nxttail[RCU_DONE_TAIL] = NULL;
tail = rdp->nxttail[RCU_DONE_TAIL]; tail = rdp->nxttail[RCU_DONE_TAIL];
for (count = RCU_NEXT_SIZE - 1; count >= 0; count--) for (i = RCU_NEXT_SIZE - 1; i >= 0; i--)
if (rdp->nxttail[count] == rdp->nxttail[RCU_DONE_TAIL]) if (rdp->nxttail[i] == rdp->nxttail[RCU_DONE_TAIL])
rdp->nxttail[count] = &rdp->nxtlist; rdp->nxttail[i] = &rdp->nxtlist;
local_irq_restore(flags); local_irq_restore(flags);
/* Invoke callbacks. */ /* Invoke callbacks. */
@ -1583,9 +1583,9 @@ static void rcu_do_batch(struct rcu_state *rsp, struct rcu_data *rdp)
if (list != NULL) { if (list != NULL) {
*tail = rdp->nxtlist; *tail = rdp->nxtlist;
rdp->nxtlist = list; rdp->nxtlist = list;
for (count = 0; count < RCU_NEXT_SIZE; count++) for (i = 0; i < RCU_NEXT_SIZE; i++)
if (&rdp->nxtlist == rdp->nxttail[count]) if (&rdp->nxtlist == rdp->nxttail[i])
rdp->nxttail[count] = tail; rdp->nxttail[i] = tail;
else else
break; break;
} }