[PATCH] drm/amdgpu: Check entity rq

[xinhui pan]

gpu recover will call sdma suspend/resume. In this period, ring will be
disabled. So the vm_pte_scheds(sdma.instance[X].ring.sched)->ready will
be false.

If we submit any jobs in this ring-disabled period. We fail to pick up
a rq for vm entity and entity->rq will set to NULL.
amdgpu_vm_sdma_commit did not check the entity->rq, so fix it. Otherwise
hit panic.

Cc: Christian König <christian.koenig at amd.com>
Cc: Alex Deucher <alexander.deucher at amd.com>
Cc: Felix Kuehling <Felix.Kuehling at amd.com>
Signed-off-by: xinhui pan <xinhui.pan at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_vm_sdma.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_sdma.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_sdma.c
index cf96c335b258..d30d103e48a2 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_sdma.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_sdma.c
@@ -95,6 +95,8 @@ static int amdgpu_vm_sdma_commit(struct amdgpu_vm_update_params *p,
 	int r;
 
 	entity = p->direct ? &p->vm->direct : &p->vm->delayed;
+	if (!entity->rq)
+		return -ENOENT;
 	ring = container_of(entity->rq->sched, struct amdgpu_ring, sched);
 
 	WARN_ON(ib->length_dw == 0);
-- 
2.17.1