drivers/infiniband/hw/cxgb4/qp.c
   129  static int alloc_host_sq(struct c4iw_rdev *rdev, struct t4_sq *sq)
   130  {
   131          sq->queue = dma_alloc_coherent(&(rdev->lldi.pdev->dev), sq->memsize,
   132                                         &(sq->dma_addr), GFP_KERNEL);
   133          if (!sq->queue)
   134                  return -ENOMEM;
   135          sq->phys_addr = virt_to_phys(sq->queue);
   136          dma_unmap_addr_set(sq, mapping, sq->dma_addr);
   137          return 0;
   138  }

Is this a bug?

Yes.  This will blow up badly on many platforms, as sq->queue
might be vmapped, ioremapped, come from a pool without page backing.