Hello Likun Gao,
Commit b412351e91bd ("drm/amdgpu: Add sdma v7_0 ip block support
(v7)") from Jul 4, 2023 (linux-next), leads to the following Smatch
static checker warning:
drivers/gpu/drm/amd/amdgpu/sdma_v7_0.c:171 sdma_v7_0_ring_set_wptr()
warn: duplicate check '*is_queue_unmap' (previous on line 161)
drivers/gpu/drm/amd/amdgpu/sdma_v7_0.c
140 static void sdma_v7_0_ring_set_wptr(struct amdgpu_ring *ring)
141 {
142 struct amdgpu_device *adev = ring->adev;
143 uint32_t *wptr_saved;
144 uint32_t *is_queue_unmap;
145 uint64_t aggregated_db_index;
146 uint32_t mqd_size = adev->mqds[AMDGPU_HW_IP_DMA].mqd_size;
147
148 DRM_DEBUG("Setting write pointer\n");
149
150 if (ring->is_mes_queue) {
151 wptr_saved = (uint32_t *)(ring->mqd_ptr + mqd_size);
152 is_queue_unmap = (uint32_t *)(ring->mqd_ptr + mqd_size +
^^^^^^^^^^^^^^^^
Set here
153 sizeof(uint32_t));
154 aggregated_db_index =
155 amdgpu_mes_get_aggregated_doorbell_index(adev,
156 ring->hw_prio);
157
158 atomic64_set((atomic64_t *)ring->wptr_cpu_addr,
159 ring->wptr << 2);
160 *wptr_saved = ring->wptr << 2;
161 if (*is_queue_unmap) {
^^^^^^^^^^^^^^^
Checked here
162 WDOORBELL64(aggregated_db_index, ring->wptr << 2);
163 DRM_DEBUG("calling WDOORBELL64(0x%08x, 0x%016llx)\n",
164 ring->doorbell_index, ring->wptr << 2);
165 WDOORBELL64(ring->doorbell_index, ring->wptr << 2);
166 } else {
167 DRM_DEBUG("calling WDOORBELL64(0x%08x, 0x%016llx)\n",
168 ring->doorbell_index, ring->wptr << 2);
169 WDOORBELL64(ring->doorbell_index, ring->wptr << 2);
170
--> 171 if (*is_queue_unmap)
^^^^^^^^^^^^^^^
This is dead code. We know it's false.
172 WDOORBELL64(aggregated_db_index,
173 ring->wptr << 2);
174 }
175 } else {
176 if (ring->use_doorbell) {
177 DRM_DEBUG("Using doorbell -- "
178 "wptr_offs == 0x%08x "
regards,
dan carpenter
