[bug report] drm/amdgpu/gfx11: add aggregated doorbell support

[Dan Carpenter]

Hello Jack Xiao,

The patch af019bef6d6f: "drm/amdgpu/gfx11: add aggregated doorbell
support" from Jul 11, 2022, leads to the following Smatch static
checker warning:

	drivers/gpu/drm/amd/amdgpu/gfx_v11_0.c:5193 gfx_v11_0_ring_set_wptr_gfx()
	warn: duplicate check '*is_queue_unmap'

drivers/gpu/drm/amd/amdgpu/gfx_v11_0.c
    5166 static void gfx_v11_0_ring_set_wptr_gfx(struct amdgpu_ring *ring)
    5167 {
    5168         struct amdgpu_device *adev = ring->adev;
    5169         uint32_t *wptr_saved;
    5170         uint32_t *is_queue_unmap;
    5171         uint64_t aggregated_db_index;
    5172         uint32_t mqd_size = adev->mqds[AMDGPU_HW_IP_GFX].mqd_size;
    5173         uint64_t wptr_tmp;
    5174 
    5175         if (ring->is_mes_queue) {
    5176                 wptr_saved = (uint32_t *)(ring->mqd_ptr + mqd_size);
    5177                 is_queue_unmap = (uint32_t *)(ring->mqd_ptr + mqd_size +
    5178                                               sizeof(uint32_t));
    5179                 aggregated_db_index =
    5180                         amdgpu_mes_get_aggregated_doorbell_index(adev,
    5181                                                                  ring->hw_prio);
    5182 
    5183                 wptr_tmp = ring->wptr & ring->buf_mask;
    5184                 atomic64_set((atomic64_t *)ring->wptr_cpu_addr, wptr_tmp);
    5185                 *wptr_saved = wptr_tmp;
    5186                 /* assume doorbell always being used by mes mapped queue */
    5187                 if (*is_queue_unmap) {
                             ^^^^^^^^^^^^^^^
Non-zero here.

    5188                         WDOORBELL64(aggregated_db_index, wptr_tmp);
    5189                         WDOORBELL64(ring->doorbell_index, wptr_tmp);
    5190                 } else {
    5191                         WDOORBELL64(ring->doorbell_index, wptr_tmp);
    5192 
--> 5193                         if (*is_queue_unmap)
                                     ^^^^^^^^^^^^^^^
You would think it's zero here.  Although, possibly this value is
getting set in another thread?

    5194                                 WDOORBELL64(aggregated_db_index, wptr_tmp);
    5195                 }
    5196         } else {
    5197                 if (ring->use_doorbell) {
    5198                         /* XXX check if swapping is necessary on BE */
    5199                         atomic64_set((atomic64_t *)ring->wptr_cpu_addr,
    5200                                      ring->wptr);
    5201                         WDOORBELL64(ring->doorbell_index, ring->wptr);
    5202                 } else {
    5203                         WREG32_SOC15(GC, 0, regCP_RB0_WPTR,
    5204                                      lower_32_bits(ring->wptr));
    5205                         WREG32_SOC15(GC, 0, regCP_RB0_WPTR_HI,
    5206                                      upper_32_bits(ring->wptr));
    5207                 }
    5208         }
    5209 }

regards,
dan carpenter