Quoting Daniel Vetter (2020-05-12 09:59:28)
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.
You can argue for enforcing might_sleep() as internal queries should be using dma_fence_is_signaled() and not dma_fence_wait_timeout(0).
Cc: linux-media@vger.kernel.org Cc: linaro-mm-sig@lists.linaro.org Cc: linux-rdma@vger.kernel.org Cc: amd-gfx@lists.freedesktop.org Cc: intel-gfx@lists.freedesktop.org Cc: Chris Wilson chris@chris-wilson.co.uk Cc: Maarten Lankhorst maarten.lankhorst@linux.intel.com Cc: Christian König christian.koenig@amd.com Signed-off-by: Daniel Vetter daniel.vetter@intel.com
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();
might_sleep_if(timeout > 0); -Chris