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>

3 files changed, 34 insertions, 10 deletions

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
index 951c8db01412..76033e2cdba8 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
@@ -738,6 +738,7 @@ struct amdgpu_ctx {
         bool                    preamble_presented;
         enum amd_sched_priority init_priority;
         enum amd_sched_priority override_priority;
+        struct mutex            lock;
 };
 
 struct amdgpu_ctx_mgr {
@@ -760,9 +761,12 @@ void amdgpu_ctx_priority_override(struct amdgpu_ctx *ctx,
 int amdgpu_ctx_ioctl(struct drm_device *dev, void *data,
                      struct drm_file *filp);
 
+int amdgpu_ctx_wait_prev_fence(struct amdgpu_ctx *ctx, unsigned ring_id);
+
 void amdgpu_ctx_mgr_init(struct amdgpu_ctx_mgr *mgr);
 void amdgpu_ctx_mgr_fini(struct amdgpu_ctx_mgr *mgr);
 
+
 /*
  * file private structure
  */
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
index 9166d5e1e557..5de092eab0fa 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
@@ -90,6 +90,8 @@ static int amdgpu_cs_parser_init(struct amdgpu_cs_parser *p, void *data)
                 goto free_chunk;
         }
 
+        mutex_lock(&p->ctx->lock);
+
         /* get chunks */
         chunk_array_user = u64_to_user_ptr(cs->in.chunks);
         if (copy_from_user(chunk_array, chunk_array_user,
@@ -737,8 +739,10 @@ static void amdgpu_cs_parser_fini(struct amdgpu_cs_parser *parser, int error,
 
         dma_fence_put(parser->fence);
 
-        if (parser->ctx)
+        if (parser->ctx) {
+                mutex_unlock(&parser->ctx->lock);
                 amdgpu_ctx_put(parser->ctx);
+        }
         if (parser->bo_list)
                 amdgpu_bo_list_put(parser->bo_list);
 
@@ -895,9 +899,7 @@ static int amdgpu_cs_ib_vm_chunk(struct amdgpu_device *adev,
                         r = amdgpu_ring_parse_cs(ring, p, j);
                         if (r)
                                 return r;
-
                 }
-
                 j++;
         }
 
@@ -985,7 +987,7 @@ static int amdgpu_cs_ib_fill(struct amdgpu_device *adev,
             parser->job->ring->funcs->type == AMDGPU_RING_TYPE_VCE))
                 return -EINVAL;
 
-        return 0;
+        return amdgpu_ctx_wait_prev_fence(parser->ctx, parser->job->ring->idx);
 }
 
 static int amdgpu_cs_process_fence_dep(struct amdgpu_cs_parser *p,
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);