i40iw: Implement get_vector_affinity API

Storage ULPs (like NVMEoF) benefit from exposing affinity mapping
per completion vector to find the optimal multi-queue affinity
assignments. The ULPs call the verbs API ib_get_vector_affinity
introduced in commit c66cd35 ("RDMA/core: expose affinity mappings per
completion vector") to get the underlying devices affinity mappings.

Add support in driver to expose the affinity masks per MSI-X
completion vector.

Signed-off-by: Shiraz Saleem <shiraz.saleem@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/hw/i40iw/i40iw_verbs.c

@@ -2728,6 +2728,25 @@ static int i40iw_destroy_ah(struct ib_ah *ah)
 	return -ENOSYS;
 }
 
+/**
+ * i40iw_get_vector_affinity - report IRQ affinity mask
+ * @ibdev: IB device
+ * @comp_vector: completion vector index
+ */
+static const struct cpumask *i40iw_get_vector_affinity(struct ib_device *ibdev,
+						       int comp_vector)
+{
+	struct i40iw_device *iwdev = to_iwdev(ibdev);
+	struct i40iw_msix_vector *msix_vec;
+
+	if (iwdev->msix_shared)
+		msix_vec = &iwdev->iw_msixtbl[comp_vector];
+	else
+		msix_vec = &iwdev->iw_msixtbl[comp_vector + 1];
+
+	return irq_get_affinity_mask(msix_vec->irq);
+}
+
 /**
  * i40iw_init_rdma_device - initialization of iwarp device
  * @iwdev: iwarp device
@@ -2824,6 +2843,7 @@ static struct i40iw_ib_device *i40iw_init_rdma_device(struct i40iw_device *iwdev
 	iwibdev->ibdev.req_notify_cq = i40iw_req_notify_cq;
 	iwibdev->ibdev.post_send = i40iw_post_send;
 	iwibdev->ibdev.post_recv = i40iw_post_recv;
+	iwibdev->ibdev.get_vector_affinity = i40iw_get_vector_affinity;
 
 	return iwibdev;
 }