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drm/nouveau: Refactor context destruction to avoid a lock ordering issue.

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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 <marcin.slusarz@gmail.com>
Signed-off-by: Francisco Jerez <currojerez@riseup.net>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
This commit is contained in:
Francisco Jerez
2010-10-18 03:53:39 +02:00
committed by Ben Skeggs
parent fcccab2e4e
commit 3945e47543
12 changed files with 116 additions and 49 deletions
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15
drivers/gpu/drm/nouveau/nv04_graph.c
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@ -412,10 +412,25 @@ int nv04_graph_create_context(struct nouveau_channel *chan)
void nv04_graph_destroy_context(struct nouveau_channel *chan)
{
struct drm_device *dev = chan->dev;
struct drm_nouveau_private *dev_priv = dev->dev_private;
struct nouveau_pgraph_engine *pgraph = &dev_priv->engine.graph;
struct graph_state *pgraph_ctx = chan->pgraph_ctx;
unsigned long flags;
spin_lock_irqsave(&dev_priv->context_switch_lock, flags);
pgraph->fifo_access(dev, false);
/* Unload the context if it's the currently active one */
if (pgraph->channel(dev) == chan)
pgraph->unload_context(dev);
/* Free the context resources */
kfree(pgraph_ctx);
chan->pgraph_ctx = NULL;
pgraph->fifo_access(dev, true);
spin_unlock_irqrestore(&dev_priv->context_switch_lock, flags);
}
int nv04_graph_load_context(struct nouveau_channel *chan)