From 3945e47543863385b54d94c94b023ee7ca9df972 Mon Sep 17 00:00:00 2001 From: Francisco Jerez Date: Mon, 18 Oct 2010 03:53:39 +0200 Subject: drm/nouveau: Refactor context destruction to avoid a lock ordering issue. The destroy_context() engine hooks call gpuobj management functions to release the channel resources, these functions use HARDIRQ-unsafe locks whereas destroy_context() is called with the HARDIRQ-safe context_switch_lock held, that's a lock ordering violation. Push the engine-specific channel destruction logic into destroy_context() and let the hardware-specific code lock and unlock when it's actually needed. Change the engine destruction order to avoid a race in the small gap between pgraph and pfifo context uninitialization. Reported-by: Marcin Slusarz Signed-off-by: Francisco Jerez Signed-off-by: Ben Skeggs --- drivers/gpu/drm/nouveau/nv04_fifo.c | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-) (limited to 'drivers/gpu/drm/nouveau/nv04_fifo.c') diff --git a/drivers/gpu/drm/nouveau/nv04_fifo.c b/drivers/gpu/drm/nouveau/nv04_fifo.c index 25c439dcdfd9..4c0d3a8fca68 100644 --- a/drivers/gpu/drm/nouveau/nv04_fifo.c +++ b/drivers/gpu/drm/nouveau/nv04_fifo.c @@ -151,10 +151,27 @@ void nv04_fifo_destroy_context(struct nouveau_channel *chan) { struct drm_device *dev = chan->dev; + struct drm_nouveau_private *dev_priv = dev->dev_private; + struct nouveau_fifo_engine *pfifo = &dev_priv->engine.fifo; + unsigned long flags; - nv_wr32(dev, NV04_PFIFO_MODE, - nv_rd32(dev, NV04_PFIFO_MODE) & ~(1 << chan->id)); + spin_lock_irqsave(&dev_priv->context_switch_lock, flags); + pfifo->reassign(dev, false); + + /* Unload the context if it's the currently active one */ + if (pfifo->channel_id(dev) == chan->id) { + pfifo->disable(dev); + pfifo->unload_context(dev); + pfifo->enable(dev); + } + + /* Keep it from being rescheduled */ + nv_mask(dev, NV04_PFIFO_MODE, 1 << chan->id, 0); + + pfifo->reassign(dev, true); + spin_unlock_irqrestore(&dev_priv->context_switch_lock, flags); + /* Free the channel resources */ nouveau_gpuobj_ref(NULL, &chan->ramfc); } -- cgit v1.2.2