This is a bit tricky, since ->notifier_lock is held while calling
dma_fence_wait we must ensure that also the read side (i.e.
dma_fence_begin_signalling) is on the same side. If we mix this up
lockdep complaints, and that's again why we want to have these
annotations.

A nice side effect of this is that because of the fs_reclaim priming
for dma_fence_enable lockdep now automatically checks for us that
nothing in here allocates memory, without even running any userptr
workloads.

Cc: linux-me...@vger.kernel.org
Cc: linaro-mm-...@lists.linaro.org
Cc: linux-r...@vger.kernel.org
Cc: amd-...@lists.freedesktop.org
Cc: intel-...@lists.freedesktop.org
Cc: Chris Wilson <ch...@chris-wilson.co.uk>
Cc: Maarten Lankhorst <maarten.lankho...@linux.intel.com>
Cc: Christian König <christian.koe...@amd.com>
Signed-off-by: Daniel Vetter <daniel.vet...@intel.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
index 7653f62b1b2d..6db3f3c629b0 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
@@ -1213,6 +1213,7 @@ static int amdgpu_cs_submit(struct amdgpu_cs_parser *p,
        struct amdgpu_job *job;
        uint64_t seq;
        int r;
+       bool fence_cookie;
 
        job = p->job;
        p->job = NULL;
@@ -1227,6 +1228,8 @@ static int amdgpu_cs_submit(struct amdgpu_cs_parser *p,
         */
        mutex_lock(&p->adev->notifier_lock);
 
+       fence_cookie = dma_fence_begin_signalling();
+
        /* If userptr are invalidated after amdgpu_cs_parser_bos(), return
         * -EAGAIN, drmIoctl in libdrm will restart the amdgpu_cs_ioctl.
         */
@@ -1264,12 +1267,14 @@ static int amdgpu_cs_submit(struct amdgpu_cs_parser *p,
        amdgpu_vm_move_to_lru_tail(p->adev, &fpriv->vm);
 
        ttm_eu_fence_buffer_objects(&p->ticket, &p->validated, p->fence);
+       dma_fence_end_signalling(fence_cookie);
        mutex_unlock(&p->adev->notifier_lock);
 
        return 0;
 
 error_abort:
        drm_sched_job_cleanup(&job->base);
+       dma_fence_end_signalling(fence_cookie);
        mutex_unlock(&p->adev->notifier_lock);
 
 error_unlock:
-- 
2.26.2

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