[POWERPC] spu sched: make addition to stop_wq and runque atomic vs wakeup
Addition to stop_wq needs to happen before adding to the runqeueue and
under the same lock so that we don't have a race window for a lost
wake up in the spu scheduler.
Signed-off-by: Luke Browning <lukebrowning@us.ibm.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>
diff --git a/arch/powerpc/platforms/cell/spufs/sched.c b/arch/powerpc/platforms/cell/spufs/sched.c
index 876828c..91030b8 100644
--- a/arch/powerpc/platforms/cell/spufs/sched.c
+++ b/arch/powerpc/platforms/cell/spufs/sched.c
@@ -236,44 +236,40 @@
* spu_add_to_rq - add a context to the runqueue
* @ctx: context to add
*/
-static void spu_add_to_rq(struct spu_context *ctx)
+static void __spu_add_to_rq(struct spu_context *ctx)
{
- spin_lock(&spu_prio->runq_lock);
- list_add_tail(&ctx->rq, &spu_prio->runq[ctx->prio]);
- set_bit(ctx->prio, spu_prio->bitmap);
- mb();
- spin_unlock(&spu_prio->runq_lock);
+ int prio = ctx->prio;
+
+ list_add_tail(&ctx->rq, &spu_prio->runq[prio]);
+ set_bit(prio, spu_prio->bitmap);
}
-static void __spu_del_from_rq(struct spu_context *ctx, int prio)
+static void __spu_del_from_rq(struct spu_context *ctx)
{
+ int prio = ctx->prio;
+
if (!list_empty(&ctx->rq))
list_del_init(&ctx->rq);
if (list_empty(&spu_prio->runq[prio]))
- clear_bit(ctx->prio, spu_prio->bitmap);
-}
-
-/**
- * spu_del_from_rq - remove a context from the runqueue
- * @ctx: context to remove
- */
-static void spu_del_from_rq(struct spu_context *ctx)
-{
- spin_lock(&spu_prio->runq_lock);
- __spu_del_from_rq(ctx, ctx->prio);
- spin_unlock(&spu_prio->runq_lock);
+ clear_bit(prio, spu_prio->bitmap);
}
static void spu_prio_wait(struct spu_context *ctx)
{
DEFINE_WAIT(wait);
+ spin_lock(&spu_prio->runq_lock);
prepare_to_wait_exclusive(&ctx->stop_wq, &wait, TASK_INTERRUPTIBLE);
if (!signal_pending(current)) {
+ __spu_add_to_rq(ctx);
+ spin_unlock(&spu_prio->runq_lock);
mutex_unlock(&ctx->state_mutex);
schedule();
mutex_lock(&ctx->state_mutex);
+ spin_lock(&spu_prio->runq_lock);
+ __spu_del_from_rq(ctx);
}
+ spin_unlock(&spu_prio->runq_lock);
__set_current_state(TASK_RUNNING);
remove_wait_queue(&ctx->stop_wq, &wait);
}
@@ -300,7 +296,7 @@
BUG_ON(list_empty(rq));
ctx = list_entry(rq->next, struct spu_context, rq);
- __spu_del_from_rq(ctx, best);
+ __spu_del_from_rq(ctx);
wake_up(&ctx->stop_wq);
}
spin_unlock(&spu_prio->runq_lock);
@@ -427,9 +423,7 @@
return 0;
}
- spu_add_to_rq(ctx);
spu_prio_wait(ctx);
- spu_del_from_rq(ctx);
} while (!signal_pending(current));
return -ERESTARTSYS;