drm/amdgpu: Move old fence waiting before reservation lock is aquired v2

Helps avoiding deadlock during GPU reset.
Added mutex to amdgpu_ctx to preserve order of fences on a ring.

v2:
Put waiting logic in a function in a seperate function in amdgpu_ctx.c

Signed-off-by: Andrey Grodzovsky <andrey.grodzovsky@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

1 files changed, 24 insertions, 6 deletions

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c
index a78b03f65c69..4309820658c4 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c
@@ -67,6 +67,8 @@ static int amdgpu_ctx_init(struct amdgpu_device *adev,
 	if (!ctx->fences)
 		return -ENOMEM;
 
+	mutex_init(&ctx->lock);
+
 	for (i = 0; i < AMDGPU_MAX_RINGS; ++i) {
 		ctx->rings[i].sequence = 1;
 		ctx->rings[i].fences = &ctx->fences[amdgpu_sched_jobs * i];
@@ -126,6 +128,8 @@ static void amdgpu_ctx_fini(struct amdgpu_ctx *ctx)
 				      &ctx->rings[i].entity);
 
 	amdgpu_queue_mgr_fini(adev, &ctx->queue_mgr);
+
+	mutex_destroy(&ctx->lock);
 }
 
 static int amdgpu_ctx_alloc(struct amdgpu_device *adev,
@@ -296,12 +300,8 @@ int amdgpu_ctx_add_fence(struct amdgpu_ctx *ctx, struct amdgpu_ring *ring,
 
 	idx = seq & (amdgpu_sched_jobs - 1);
 	other = cring->fences[idx];
-	if (other) {
-		signed long r;
-		r = dma_fence_wait_timeout(other, true, MAX_SCHEDULE_TIMEOUT);
-		if (r < 0)
-			return r;
-	}
+	if (other)
+		BUG_ON(!dma_fence_is_signaled(other));
 
 	dma_fence_get(fence);
 
@@ -372,6 +372,24 @@ void amdgpu_ctx_priority_override(struct amdgpu_ctx *ctx,
 	}
 }
 
+int amdgpu_ctx_wait_prev_fence(struct amdgpu_ctx *ctx, unsigned ring_id)
+{
+	struct amdgpu_ctx_ring *cring = &ctx->rings[ring_id];
+	unsigned idx = cring->sequence & (amdgpu_sched_jobs - 1);
+	struct dma_fence *other = cring->fences[idx];
+
+	if (other) {
+		signed long r;
+		r = dma_fence_wait_timeout(other, false, MAX_SCHEDULE_TIMEOUT);
+		if (r < 0) {
+			DRM_ERROR("Error (%ld) waiting for fence!\n", r);
+			return r;
+		}
+	}
+
+	return 0;
+}
+
 void amdgpu_ctx_mgr_init(struct amdgpu_ctx_mgr *mgr)
 {
 	mutex_init(&mgr->lock);