From: Rob Clark <robdcl...@chromium.org>

Use drm_gpuvm_bo_obtain() in the synchronous part of the VM_BIND submit,
to hold a reference to the vm_bo for the duration of the submit.  This
ensures that the vm_bo already exists before the async part of the job,
which is in the fence signalling path (and therefore cannot allocate
memory).

Signed-off-by: Rob Clark <robdcl...@chromium.org>
---
 drivers/gpu/drm/msm/msm_gem.h     |  1 +
 drivers/gpu/drm/msm/msm_gem_vma.c | 19 +++++++++++++++++--
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/msm/msm_gem.h b/drivers/gpu/drm/msm/msm_gem.h
index cb76959fa8a8..d2ffaa11ec1a 100644
--- a/drivers/gpu/drm/msm/msm_gem.h
+++ b/drivers/gpu/drm/msm/msm_gem.h
@@ -369,6 +369,7 @@ struct msm_gem_submit {
                uint32_t flags;
                uint32_t handle;
                struct drm_gem_object *obj;
+               struct drm_gpuvm_bo *vm_bo;
                uint64_t iova;
                uint64_t bo_offset;
                uint64_t range;
diff --git a/drivers/gpu/drm/msm/msm_gem_vma.c 
b/drivers/gpu/drm/msm/msm_gem_vma.c
index 5c7d44b004fb..b1808d95002f 100644
--- a/drivers/gpu/drm/msm/msm_gem_vma.c
+++ b/drivers/gpu/drm/msm/msm_gem_vma.c
@@ -278,8 +278,18 @@ msm_vma_job_prepare(struct msm_gem_submit *submit)
        for (int i = 0; i < submit->nr_bos; i++) {
                unsigned op = submit->bos[i].flags & MSM_SUBMIT_BO_OP_MASK;
 
-               if (submit->bos[i].obj)
-                       msm_gem_assert_locked(submit->bos[i].obj);
+               if (submit->bos[i].obj) {
+                       struct drm_gem_object *obj = submit->bos[i].obj;
+
+                       msm_gem_assert_locked(obj);
+
+                       /*
+                        * Ensure the vm_bo is already allocated by
+                        * holding a ref until the submit is retired
+                        */
+                       submit->bos[i].vm_bo =
+                               drm_gpuvm_bo_obtain(submit->vm, obj);
+               }
 
                /*
                 * OP_MAP/OP_MAP_NULL has one new VMA for the new mapping,
@@ -309,6 +319,11 @@ msm_vma_job_cleanup(struct msm_gem_submit *submit)
 {
        struct drm_gpuva *vma;
 
+       for (int i = 0; i < submit->nr_bos; i++) {
+               /* If we're holding an extra ref to the vm_bo, drop it now: */
+               drm_gpuvm_bo_put(submit->bos[i].vm_bo);
+       }
+
        while (!list_empty(&submit->preallocated_vmas)) {
                vma = list_first_entry(&submit->preallocated_vmas,
                                       struct drm_gpuva,
-- 
2.48.1

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