[bug report] drm/amdgpu/mes: use ring for kernel queue submission

[Dan Carpenter]

Hello Jack Xiao,

Commit d0c423b64765 ("drm/amdgpu/mes: use ring for kernel queue
submission") from Mar 27, 2020 (linux-next), leads to the following
Smatch static checker warning:

	drivers/gpu/drm/amd/amdgpu/amdgpu_mes.c:1240 amdgpu_mes_add_ring()
	warn: double unlock '&adev->mes.mutex_hidden' (orig line 1213)

drivers/gpu/drm/amd/amdgpu/amdgpu_mes.c
    1143 int amdgpu_mes_add_ring(struct amdgpu_device *adev, int gang_id,
    1144                         int queue_type, int idx,
    1145                         struct amdgpu_mes_ctx_data *ctx_data,
    1146                         struct amdgpu_ring **out)
    1147 {
    1148         struct amdgpu_ring *ring;
    1149         struct amdgpu_mes_gang *gang;
    1150         struct amdgpu_mes_queue_properties qprops = {0};
    1151         int r, queue_id, pasid;
    1152 
    1153         /*
    1154          * Avoid taking any other locks under MES lock to avoid circular
    1155          * lock dependencies.
    1156          */
    1157         amdgpu_mes_lock(&adev->mes);
    1158         gang = idr_find(&adev->mes.gang_id_idr, gang_id);
    1159         if (!gang) {
    1160                 DRM_ERROR("gang id %d doesn't exist\n", gang_id);
    1161                 amdgpu_mes_unlock(&adev->mes);
    1162                 return -EINVAL;
    1163         }
    1164         pasid = gang->process->pasid;
    1165 
    1166         ring = kzalloc(sizeof(struct amdgpu_ring), GFP_KERNEL);
    1167         if (!ring) {
    1168                 amdgpu_mes_unlock(&adev->mes);
    1169                 return -ENOMEM;
    1170         }
    1171 
    1172         ring->ring_obj = NULL;
    1173         ring->use_doorbell = true;
    1174         ring->is_mes_queue = true;
    1175         ring->mes_ctx = ctx_data;
    1176         ring->idx = idx;
    1177         ring->no_scheduler = true;
    1178 
    1179         if (queue_type == AMDGPU_RING_TYPE_COMPUTE) {
    1180                 int offset = offsetof(struct amdgpu_mes_ctx_meta_data,
    1181                                       compute[ring->idx].mec_hpd);
    1182                 ring->eop_gpu_addr =
    1183                         amdgpu_mes_ctx_get_offs_gpu_addr(ring, offset);
    1184         }
    1185 
    1186         switch (queue_type) {
    1187         case AMDGPU_RING_TYPE_GFX:
    1188                 ring->funcs = adev->gfx.gfx_ring[0].funcs;
    1189                 ring->me = adev->gfx.gfx_ring[0].me;
    1190                 ring->pipe = adev->gfx.gfx_ring[0].pipe;
    1191                 break;
    1192         case AMDGPU_RING_TYPE_COMPUTE:
    1193                 ring->funcs = adev->gfx.compute_ring[0].funcs;
    1194                 ring->me = adev->gfx.compute_ring[0].me;
    1195                 ring->pipe = adev->gfx.compute_ring[0].pipe;
    1196                 break;
    1197         case AMDGPU_RING_TYPE_SDMA:
    1198                 ring->funcs = adev->sdma.instance[0].ring.funcs;
    1199                 break;
    1200         default:
    1201                 BUG();
    1202         }
    1203 
    1204         r = amdgpu_ring_init(adev, ring, 1024, NULL, 0,
    1205                              AMDGPU_RING_PRIO_DEFAULT, NULL);
    1206         if (r)
    1207                 goto clean_up_memory;
    1208 
    1209         amdgpu_mes_ring_to_queue_props(adev, ring, &qprops);
    1210 
    1211         dma_fence_wait(gang->process->vm->last_update, false);
    1212         dma_fence_wait(ctx_data->meta_data_va->last_pt_update, false);
    1213         amdgpu_mes_unlock(&adev->mes);
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

    1214 
    1215         r = amdgpu_mes_add_hw_queue(adev, gang_id, &qprops, &queue_id);
    1216         if (r)
    1217                 goto clean_up_ring;
                         ^^^^^^^^^^^^^^^^^^

    1218 
    1219         ring->hw_queue_id = queue_id;
    1220         ring->doorbell_index = qprops.doorbell_off;
    1221 
    1222         if (queue_type == AMDGPU_RING_TYPE_GFX)
    1223                 sprintf(ring->name, "gfx_%d.%d.%d", pasid, gang_id, queue_id);
    1224         else if (queue_type == AMDGPU_RING_TYPE_COMPUTE)
    1225                 sprintf(ring->name, "compute_%d.%d.%d", pasid, gang_id,
    1226                         queue_id);
    1227         else if (queue_type == AMDGPU_RING_TYPE_SDMA)
    1228                 sprintf(ring->name, "sdma_%d.%d.%d", pasid, gang_id,
    1229                         queue_id);
    1230         else
    1231                 BUG();
    1232 
    1233         *out = ring;
    1234         return 0;
    1235 
    1236 clean_up_ring:
    1237         amdgpu_ring_fini(ring);
    1238 clean_up_memory:
    1239         kfree(ring);
--> 1240         amdgpu_mes_unlock(&adev->mes);
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

    1241         return r;
    1242 }

regards,
dan carpenter