[bug report] drm/amdgpu: Add sdma v7_0 ip block support (v7)

[Dan Carpenter]

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