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Commit 4e0f4ed0 authored by Luke Browning's avatar Luke Browning Committed by Arnd Bergmann
Browse files

[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: default avatarLuke Browning <lukebrowning@us.ibm.com>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarArnd Bergmann <arnd.bergmann@de.ibm.com>
parent 7ec18ab9

arch/powerpc/platforms/cell/spufs/sched.c

+16 −22
Original line number Diff line number Diff line
@@ -236,44 +236,40 @@ static void spu_unbind_context(struct spu *spu, struct spu_context *ctx) 
 * 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 @@ static void spu_reschedule(struct spu *spu) 
		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 @@ int spu_activate(struct spu_context *ctx, unsigned long flags) 
			return 0;

		}



		spu_add_to_rq(ctx);

		spu_prio_wait(ctx);

		spu_del_from_rq(ctx);

	} while (!signal_pending(current));



	return -ERESTARTSYS;