Am 12.05.20 um 10:59 schrieb Daniel Vetter:
But only for non-zero timeout, to avoid false positives.
One question here is whether the might_sleep should be unconditional,
or only for real timeouts. I'm not sure, so went with the more
defensive option. But in the interest of locking down the cross-driver
dma_fence rules we might want to be more aggressive.
Cc: linux-media@xxxxxxxxxxxxxxx
Cc: linaro-mm-sig@xxxxxxxxxxxxxxxx
Cc: linux-rdma@xxxxxxxxxxxxxxx
Cc: amd-gfx@xxxxxxxxxxxxxxxxxxxxx
Cc: intel-gfx@xxxxxxxxxxxxxxxxxxxxx
Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx>
Cc: Christian König <christian.koenig@xxxxxxx>
Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxxx>
---
drivers/dma-buf/dma-fence.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c
index 052a41e2451c..6802125349fb 100644
--- a/drivers/dma-buf/dma-fence.c
+++ b/drivers/dma-buf/dma-fence.c
@@ -208,6 +208,9 @@ dma_fence_wait_timeout(struct dma_fence *fence, bool intr, signed long timeout)
if (WARN_ON(timeout < 0))
return -EINVAL;
+ if (timeout > 0)
+ might_sleep();
+
I would rather like to see might_sleep() called here all the time even
with timeout==0.
IIRC I removed the code in TTM abusing this in atomic context quite a
while ago, but could be that some leaked in again or it is called in
atomic context elsewhere as well.
Christian.
trace_dma_fence_wait_start(fence);
if (fence->ops->wait)
ret = fence->ops->wait(fence, intr, timeout);
