drm/i915: Annotate dma_fence_work

i915 does tons of allocations from this worker, which lockdep catches.

Also generic infrastructure like this with big potential for how
dma_fence or other cross driver contracts work, really should be
reviewed on dri-devel. Implementing custom wheels for everything
within the driver is a classic case of "platform problem" [1]. Which in
upstream we really shouldn't have.

Since there's no quick way to solve these splats (dma_fence_work is
used a bunch in basic buffer management and command submission) like
for amdgpu, I'm giving up at this point here. Annotating i915
scheduler and gpu reset could would be interesting, but since lockdep
is one-shot we can't see what surprises would lurk there.

1: https://lwn.net/Articles/443531/
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>

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/i915_sw_fence_work.c b/drivers/gpu/drm/i915/i915_sw_fence_work.c
index d2e56b387993..be114acb7dc6 100644
--- a/drivers/gpu/drm/i915/i915_sw_fence_work.c
+++ b/drivers/gpu/drm/i915/i915_sw_fence_work.c
@@ -16,10 +16,14 @@ static void fence_complete(struct dma_fence_work *f)
 static void fence_work(struct work_struct *work)
 {
 	struct dma_fence_work *f = container_of(work, typeof(*f), work);
+	bool fence_cookie;
+
+	fence_cookie = dma_fence_begin_signalling();
 
 	f->ops->work(f);
 
 	fence_complete(f);
+	dma_fence_end_signalling(fence_cookie);
 	dma_fence_put(&f->dma);
 }