IB/core: Add cross-channel support

The cross-channel feature allows to execute WQEs that involve
synchronization of I/O operations’ on different QPs.

This capability enables to program complex flows with a single
function call, hereby significantly reducing overhead associated
with I/O processing.

Cross-channel operations support is indicated by HCA capability
information.

The queue pairs can be configured to work as a “sync master queue”
or “sync slave queues”.

The added flags are:

1. Device capability flag IB_DEVICE_CROSS_CHANNEL for the
   devices that can perform cross-channel operations.

2. CQ property flag IB_CQ_FLAGS_IGNORE_OVERRUN to disable CQ overrun
   check. This check is useless in cross-channel scenario.

3. QP property flags to indicate if queues are slave or master:
   * IB_QP_CREATE_MANAGED_SEND indicates that posted send work requests
     will not be executed immediately and requires enabling.
   * IB_QP_CREATE_MANAGED_RECV indicates that posted receive work
     requests will not be executed immediately and requires enabling.
   * IB_QP_CREATE_CROSS_CHANNEL declares the QP to work in cross-channel
     mode. If IB_QP_CREATE_MANAGED_SEND and IB_QP_CREATE_MANAGED_RECV are
     not provided, this QP will be sync master queue, else it will be sync
     slave.

Reviewed-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

diff --git a/drivers/infiniband/core/uverbs_cmd.c b/drivers/infiniband/core/uverbs_cmd.c
index 0a84182d277fb856f83de6cbd0c0543b6297e248..6ffc9c4e93afb4efa27fe6f3c17fc3cdf41d8c21 100644 (file)
--- a/drivers/infiniband/core/uverbs_cmd.c
+++ b/drivers/infiniband/core/uverbs_cmd.c
@@ -1824,7 +1824,10 @@ static int create_qp(struct ib_uverbs_file *file,
                      sizeof(cmd->create_flags))
                attr.create_flags = cmd->create_flags;
 
-       if (attr.create_flags & ~IB_QP_CREATE_BLOCK_MULTICAST_LOOPBACK) {
+       if (attr.create_flags & ~(IB_QP_CREATE_BLOCK_MULTICAST_LOOPBACK |
+                               IB_QP_CREATE_CROSS_CHANNEL |
+                               IB_QP_CREATE_MANAGED_SEND |
+                               IB_QP_CREATE_MANAGED_RECV)) {
                ret = -EINVAL;
                goto err_put;
        }

diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h
index 862b8a07c028e95acba55877ab5d3f3f9cc6cc7f..75fcc97886de026969e61f7c87a1df24b7337499 100644 (file)
--- a/include/rdma/ib_verbs.h
+++ b/include/rdma/ib_verbs.h
@@ -201,6 +201,13 @@ enum ib_device_cap_flags {
        IB_DEVICE_MEM_WINDOW_TYPE_2B            = (1 << 24),
        IB_DEVICE_RC_IP_CSUM                    = (1 << 25),
        IB_DEVICE_RAW_IP_CSUM                   = (1 << 26),
+       /*
+        * Devices should set IB_DEVICE_CROSS_CHANNEL if they
+        * support execution of WQEs that involve synchronization
+        * of I/O operations with single completion queue managed
+        * by hardware.
+        */
+       IB_DEVICE_CROSS_CHANNEL         = (1 << 27),
        IB_DEVICE_MANAGED_FLOW_STEERING         = (1 << 29),
        IB_DEVICE_SIGNATURE_HANDOVER            = (1 << 30),
        IB_DEVICE_ON_DEMAND_PAGING              = (1 << 31),
@@ -246,6 +253,7 @@ struct ib_odp_caps {
 
 enum ib_cq_creation_flags {
        IB_CQ_FLAGS_TIMESTAMP_COMPLETION   = 1 << 0,
+       IB_CQ_FLAGS_IGNORE_OVERRUN         = 1 << 1,
 };
 
 struct ib_cq_init_attr {
@@ -950,6 +958,9 @@ enum ib_qp_type {
 enum ib_qp_create_flags {
        IB_QP_CREATE_IPOIB_UD_LSO               = 1 << 0,
        IB_QP_CREATE_BLOCK_MULTICAST_LOOPBACK   = 1 << 1,
+       IB_QP_CREATE_CROSS_CHANNEL              = 1 << 2,
+       IB_QP_CREATE_MANAGED_SEND               = 1 << 3,
+       IB_QP_CREATE_MANAGED_RECV               = 1 << 4,
        IB_QP_CREATE_NETIF_QP                   = 1 << 5,
        IB_QP_CREATE_SIGNATURE_EN               = 1 << 6,
        IB_QP_CREATE_USE_GFP_NOIO               = 1 << 7,