From 3aeffc46afde05140551abb49efaa4563adba38c Mon Sep 17 00:00:00 2001 From: =?utf8?q?H=C3=A5kon=20Bugge?= Date: Wed, 31 Mar 2021 20:43:13 +0200 Subject: [PATCH] IB/cma: Introduce rdma_set_min_rnr_timer() MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Introduce the ability for kernel ULPs to adjust the minimum RNR Retry timer. The INIT -> RTR transition executed by RDMA CM will be used for this adjustment. This avoids an additional ib_modify_qp() call. rdma_set_min_rnr_timer() must be called before the call to rdma_connect() on the active side and before the call to rdma_accept() on the passive side. The default value of RNR Retry timer is zero, which translates to 655 ms. When the receiver is not ready to accept a send messages, it encodes the RNR Retry timer value in the NAK. The requestor will then wait at least the specified time value before retrying the send. The 5-bit value to be supplied to the rdma_set_min_rnr_timer() is documented in IBTA Table 45: "Encoding for RNR NAK Timer Field". Link: https://lore.kernel.org/r/1617216194-12890-2-git-send-email-haakon.bugge@oracle.com Signed-off-by: HÃ¥kon Bugge Acked-by: Jason Gunthorpe Signed-off-by: Jason Gunthorpe --- drivers/infiniband/core/cma.c | 41 ++++++++++++++++++++++++++++++++++++++ drivers/infiniband/core/cma_priv.h | 2 ++ include/rdma/rdma_cm.h | 2 ++ 3 files changed, 45 insertions(+) diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c index ca5ff35a5dc6..bb7bd024f3bd 100644 --- a/drivers/infiniband/core/cma.c +++ b/drivers/infiniband/core/cma.c @@ -843,6 +843,7 @@ __rdma_create_id(struct net *net, rdma_cm_event_handler event_handler, id_priv->id.qp_type = qp_type; id_priv->tos_set = false; id_priv->timeout_set = false; + id_priv->min_rnr_timer_set = false; id_priv->gid_type = IB_GID_TYPE_IB; spin_lock_init(&id_priv->lock); mutex_init(&id_priv->qp_mutex); @@ -1133,6 +1134,9 @@ int rdma_init_qp_attr(struct rdma_cm_id *id, struct ib_qp_attr *qp_attr, if ((*qp_attr_mask & IB_QP_TIMEOUT) && id_priv->timeout_set) qp_attr->timeout = id_priv->timeout; + if ((*qp_attr_mask & IB_QP_MIN_RNR_TIMER) && id_priv->min_rnr_timer_set) + qp_attr->min_rnr_timer = id_priv->min_rnr_timer; + return ret; } EXPORT_SYMBOL(rdma_init_qp_attr); @@ -2608,6 +2612,43 @@ int rdma_set_ack_timeout(struct rdma_cm_id *id, u8 timeout) } EXPORT_SYMBOL(rdma_set_ack_timeout); +/** + * rdma_set_min_rnr_timer() - Set the minimum RNR Retry timer of the + * QP associated with a connection identifier. + * @id: Communication identifier to associated with service type. + * @min_rnr_timer: 5-bit value encoded as Table 45: "Encoding for RNR NAK + * Timer Field" in the IBTA specification. + * + * This function should be called before rdma_connect() on active + * side, and on passive side before rdma_accept(). The timer value + * will be associated with the local QP. When it receives a send it is + * not read to handle, typically if the receive queue is empty, an RNR + * Retry NAK is returned to the requester with the min_rnr_timer + * encoded. The requester will then wait at least the time specified + * in the NAK before retrying. The default is zero, which translates + * to a minimum RNR Timer value of 655 ms. + * + * Return: 0 for success + */ +int rdma_set_min_rnr_timer(struct rdma_cm_id *id, u8 min_rnr_timer) +{ + struct rdma_id_private *id_priv; + + /* It is a five-bit value */ + if (min_rnr_timer & 0xe0) + return -EINVAL; + + if (WARN_ON(id->qp_type != IB_QPT_RC && id->qp_type != IB_QPT_XRC_TGT)) + return -EINVAL; + + id_priv = container_of(id, struct rdma_id_private, id); + id_priv->min_rnr_timer = min_rnr_timer; + id_priv->min_rnr_timer_set = true; + + return 0; +} +EXPORT_SYMBOL(rdma_set_min_rnr_timer); + static void cma_query_handler(int status, struct sa_path_rec *path_rec, void *context) { diff --git a/drivers/infiniband/core/cma_priv.h b/drivers/infiniband/core/cma_priv.h index 8af6af4bbf6e..5c463da99845 100644 --- a/drivers/infiniband/core/cma_priv.h +++ b/drivers/infiniband/core/cma_priv.h @@ -86,9 +86,11 @@ struct rdma_id_private { u8 tos; u8 tos_set:1; u8 timeout_set:1; + u8 min_rnr_timer_set:1; u8 reuseaddr; u8 afonly; u8 timeout; + u8 min_rnr_timer; enum ib_gid_type gid_type; /* diff --git a/include/rdma/rdma_cm.h b/include/rdma/rdma_cm.h index b2eed6d30543..d989f030fae0 100644 --- a/include/rdma/rdma_cm.h +++ b/include/rdma/rdma_cm.h @@ -331,6 +331,8 @@ int rdma_set_reuseaddr(struct rdma_cm_id *id, int reuse); int rdma_set_afonly(struct rdma_cm_id *id, int afonly); int rdma_set_ack_timeout(struct rdma_cm_id *id, u8 timeout); + +int rdma_set_min_rnr_timer(struct rdma_cm_id *id, u8 min_rnr_timer); /** * rdma_get_service_id - Return the IB service ID for a specified address. * @id: Communication identifier associated with the address. -- 2.11.0