From 937c3471cc8b7ef8f9e382d9e4ec232db151ea7b Mon Sep 17 00:00:00 2001 From: Francisco Jerez Date: Wed, 8 Dec 2010 02:35:45 +0100 Subject: drm/nouveau: Avoid potential race between nouveau_fence_update() and context takedown. Signed-off-by: Francisco Jerez Signed-off-by: Ben Skeggs --- drivers/gpu/drm/nouveau/nouveau_fence.c | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-) diff --git a/drivers/gpu/drm/nouveau/nouveau_fence.c b/drivers/gpu/drm/nouveau/nouveau_fence.c index 01290d2952ae..374a9793b85f 100644 --- a/drivers/gpu/drm/nouveau/nouveau_fence.c +++ b/drivers/gpu/drm/nouveau/nouveau_fence.c @@ -77,14 +77,17 @@ nouveau_fence_update(struct nouveau_channel *chan) spin_lock(&chan->fence.lock); - if (USE_REFCNT(dev)) - sequence = nvchan_rd32(chan, 0x48); - else - sequence = atomic_read(&chan->fence.last_sequence_irq); - - if (chan->fence.sequence_ack == sequence) - goto out; - chan->fence.sequence_ack = sequence; + /* Fetch the last sequence if the channel is still up and running */ + if (likely(!list_empty(&chan->fence.pending))) { + if (USE_REFCNT(dev)) + sequence = nvchan_rd32(chan, 0x48); + else + sequence = atomic_read(&chan->fence.last_sequence_irq); + + if (chan->fence.sequence_ack == sequence) + goto out; + chan->fence.sequence_ack = sequence; + } list_for_each_entry_safe(fence, tmp, &chan->fence.pending, entry) { sequence = fence->sequence; -- cgit v1.2.1