drm/amdgpu: grab the id mgr lock while accessing passid_mapping

Need to make sure that we actually dropping the right fence.
Could be done with RCU as well, but to complicated for a fix.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Chunming Zhou <david1.zhou@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
index 5acedba..17aca26 100644 (file)
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
@@ -1036,10 +1036,8 @@ int amdgpu_vm_flush(struct amdgpu_ring *ring, struct amdgpu_job *job, bool need_
                id->oa_base != job->oa_base ||
                id->oa_size != job->oa_size);
        bool vm_flush_needed = job->vm_needs_flush;
-       bool pasid_mapping_needed = id->pasid != job->pasid ||
-               !id->pasid_mapping ||
-               !dma_fence_is_signaled(id->pasid_mapping);
        struct dma_fence *fence = NULL;
+       bool pasid_mapping_needed;
        unsigned patch_offset = 0;
        int r;
 
@@ -1049,6 +1047,12 @@ int amdgpu_vm_flush(struct amdgpu_ring *ring, struct amdgpu_job *job, bool need_
                pasid_mapping_needed = true;
        }
 
+       mutex_lock(&id_mgr->lock);
+       if (id->pasid != job->pasid || !id->pasid_mapping ||
+           !dma_fence_is_signaled(id->pasid_mapping))
+               pasid_mapping_needed = true;
+       mutex_unlock(&id_mgr->lock);
+
        gds_switch_needed &= !!ring->funcs->emit_gds_switch;
        vm_flush_needed &= !!ring->funcs->emit_vm_flush  &&
                        job->vm_pd_addr != AMDGPU_BO_INVALID_OFFSET;
@@ -1088,9 +1092,11 @@ int amdgpu_vm_flush(struct amdgpu_ring *ring, struct amdgpu_job *job, bool need_
        }
 
        if (pasid_mapping_needed) {
+               mutex_lock(&id_mgr->lock);
                id->pasid = job->pasid;
                dma_fence_put(id->pasid_mapping);
                id->pasid_mapping = dma_fence_get(fence);
+               mutex_unlock(&id_mgr->lock);
        }
        dma_fence_put(fence);