RDMA/core: expose affinity mappings per completion vector

This will allow ULPs to intelligently locate threads based
on completion vector cpu affinity mappings. In case the
driver does not expose a get_vector_affinity callout, return
NULL so the caller can maintain a fallback logic.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Håkon Bugge <haakon.bugge@oracle.com>
Acked-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Doug Ledford <dledford@redhat.com>

diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h
index b5732432bb297dbf6067ae34b16c00073cb2949d..73ed2e4e802fcbb75d879a9ec0ca8076e1945818 100644 (file)
--- a/include/rdma/ib_verbs.h
+++ b/include/rdma/ib_verbs.h
@@ -2296,6 +2296,8 @@ struct ib_device {
         */
        int (*get_port_immutable)(struct ib_device *, u8, struct ib_port_immutable *);
        void (*get_dev_fw_str)(struct ib_device *, char *str, size_t str_len);
+       const struct cpumask *(*get_vector_affinity)(struct ib_device *ibdev,
+                                                    int comp_vector);
 };
 
 struct ib_client {
@@ -3706,4 +3708,26 @@ static inline enum rdma_ah_attr_type rdma_ah_find_type(struct ib_device *dev,
        else
                return RDMA_AH_ATTR_TYPE_IB;
 }
+
+/**
+ * ib_get_vector_affinity - Get the affinity mappings of a given completion
+ *   vector
+ * @device:         the rdma device
+ * @comp_vector:    index of completion vector
+ *
+ * Returns NULL on failure, otherwise a corresponding cpu map of the
+ * completion vector (returns all-cpus map if the device driver doesn't
+ * implement get_vector_affinity).
+ */
+static inline const struct cpumask *
+ib_get_vector_affinity(struct ib_device *device, int comp_vector)
+{
+       if (comp_vector < 0 || comp_vector >= device->num_comp_vectors ||
+           !device->get_vector_affinity)
+               return NULL;
+
+       return device->get_vector_affinity(device, comp_vector);
+
+}
+
 #endif /* IB_VERBS_H */