[PATCH 10/18] drm/amdgpu: use dma-fence annotations in cs_submit()

Daniel Vetter
2020-06-04T08:12:52Z

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-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/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 a25fb59c127c..e109666aec14 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
@@ -1212,6 +1212,7 @@ 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;
@@ -1226,6 +1227,8 @@ 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.
*/
@@ -1262,12 +1265,14 @@ 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