From: Jason Gunthorpe <jgg@mellanox.com>
Date: Wed, 13 Jun 2018 10:22:05 +0300
Subject: IB{cm, core}: Introduce and use ah_attr copy, move, replace APIs
Patch-mainline: v4.19-rc1
Git-commit: d97099fe53ed9ab8b17d084bed0099feb08a48c1
References: bsc#1103992 FATE#326009

Introduce AH attribute copy, move and replace APIs to be used by core and
provider drivers.

In CM code flow when ah attribute might be re-initialized twice while
processing incoming request, or initialized once while from path record
while sending out CM requests. Therefore use rdma_move_ah_attr API to
handle such scenarios instead of memcpy().

Provider drivers keeps a copy ah_attr during the lifetime of the ah.
Therefore, use rdma_replace_ah_attr() which conditionally release
reference to old ah_attr and holds reference to new attribute whose
referrence is released when the AH is freed.

Signed-off-by: Parav Pandit <parav@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/infiniband/core/cm.c       |    4 +-
 drivers/infiniband/core/verbs.c    |   54 +++++++++++++++++++++++++++++++++++++
 drivers/infiniband/hw/qedr/verbs.c |    3 +-
 drivers/infiniband/sw/rdmavt/ah.c  |    4 ++
 drivers/infiniband/sw/rdmavt/qp.c  |    6 ++--
 include/rdma/ib_verbs.h            |    5 +++
 6 files changed, 70 insertions(+), 6 deletions(-)

--- a/drivers/infiniband/core/cm.c
+++ b/drivers/infiniband/core/cm.c
@@ -474,7 +474,7 @@ static int cm_init_av_for_lap(struct cm_
 	if (ret)
 		return ret;
 
-	memcpy(&av->ah_attr, &new_ah_attr, sizeof(new_ah_attr));
+	rdma_move_ah_attr(&av->ah_attr, &new_ah_attr);
 	return 0;
 }
 
@@ -569,7 +569,7 @@ static int cm_init_av_by_path(struct sa_
 	ret = add_cm_id_to_port_list(cm_id_priv, av, port);
 	if (ret)
 		return ret;
-	memcpy(&av->ah_attr, &new_ah_attr, sizeof(new_ah_attr));
+	rdma_move_ah_attr(&av->ah_attr, &new_ah_attr);
 	return 0;
 }
 
--- a/drivers/infiniband/core/verbs.c
+++ b/drivers/infiniband/core/verbs.c
@@ -326,6 +326,60 @@ EXPORT_SYMBOL(ib_dealloc_pd);
 
 /* Address handles */
 
+/**
+ * rdma_copy_ah_attr - Copy rdma ah attribute from source to destination.
+ * @dest:       Pointer to destination ah_attr. Contents of the destination
+ *              pointer is assumed to be invalid and attribute are overwritten.
+ * @src:        Pointer to source ah_attr.
+ */
+void rdma_copy_ah_attr(struct rdma_ah_attr *dest,
+		       const struct rdma_ah_attr *src)
+{
+	*dest = *src;
+	if (dest->grh.sgid_attr)
+		rdma_hold_gid_attr(dest->grh.sgid_attr);
+}
+EXPORT_SYMBOL(rdma_copy_ah_attr);
+
+/**
+ * rdma_replace_ah_attr - Replace valid ah_attr with new new one.
+ * @old:        Pointer to existing ah_attr which needs to be replaced.
+ *              old is assumed to be valid or zero'd
+ * @new:        Pointer to the new ah_attr.
+ *
+ * rdma_replace_ah_attr() first releases any reference in the old ah_attr if
+ * old the ah_attr is valid; after that it copies the new attribute and holds
+ * the reference to the replaced ah_attr.
+ */
+void rdma_replace_ah_attr(struct rdma_ah_attr *old,
+			  const struct rdma_ah_attr *new)
+{
+	rdma_destroy_ah_attr(old);
+	*old = *new;
+	if (old->grh.sgid_attr)
+		rdma_hold_gid_attr(old->grh.sgid_attr);
+}
+EXPORT_SYMBOL(rdma_replace_ah_attr);
+
+/**
+ * rdma_move_ah_attr - Move ah_attr pointed by source to destination.
+ * @dest:       Pointer to destination ah_attr to copy to.
+ *              dest is assumed to be valid or zero'd
+ * @src:        Pointer to the new ah_attr.
+ *
+ * rdma_move_ah_attr() first releases any reference in the destination ah_attr
+ * if it is valid. This also transfers ownership of internal references from
+ * src to dest, making src invalid in the process. No new reference of the src
+ * ah_attr is taken.
+ */
+void rdma_move_ah_attr(struct rdma_ah_attr *dest, struct rdma_ah_attr *src)
+{
+	rdma_destroy_ah_attr(dest);
+	*dest = *src;
+	src->grh.sgid_attr = NULL;
+}
+EXPORT_SYMBOL(rdma_move_ah_attr);
+
 /*
  * Validate that the rdma_ah_attr is valid for the device before passing it
  * off to the driver.
--- a/drivers/infiniband/hw/qedr/verbs.c
+++ b/drivers/infiniband/hw/qedr/verbs.c
@@ -2305,7 +2305,7 @@ struct ib_ah *qedr_create_ah(struct ib_p
 	if (!ah)
 		return ERR_PTR(-ENOMEM);
 
-	ah->attr = *attr;
+	rdma_copy_ah_attr(&ah->attr, attr);
 
 	return &ah->ibah;
 }
@@ -2314,6 +2314,7 @@ int qedr_destroy_ah(struct ib_ah *ibah)
 {
 	struct qedr_ah *ah = get_qedr_ah(ibah);
 
+	rdma_destroy_ah_attr(&ah->attr);
 	kfree(ah);
 	return 0;
 }
--- a/drivers/infiniband/sw/rdmavt/ah.c
+++ b/drivers/infiniband/sw/rdmavt/ah.c
@@ -120,7 +120,8 @@ struct ib_ah *rvt_create_ah(struct ib_pd
 	dev->n_ahs_allocated++;
 	spin_unlock_irqrestore(&dev->n_ahs_lock, flags);
 
-	ah->attr = *ah_attr;
+	rdma_copy_ah_attr(&ah->attr, ah_attr);
+
 	atomic_set(&ah->refcount, 0);
 
 	if (dev->driver_f.notify_new_ah)
@@ -148,6 +149,7 @@ int rvt_destroy_ah(struct ib_ah *ibah)
 	dev->n_ahs_allocated--;
 	spin_unlock_irqrestore(&dev->n_ahs_lock, flags);
 
+	rdma_destroy_ah_attr(&ah->attr);
 	kfree(ah);
 
 	return 0;
--- a/drivers/infiniband/sw/rdmavt/qp.c
+++ b/drivers/infiniband/sw/rdmavt/qp.c
@@ -1339,13 +1339,13 @@ int rvt_modify_qp(struct ib_qp *ibqp, st
 		qp->qp_access_flags = attr->qp_access_flags;
 
 	if (attr_mask & IB_QP_AV) {
-		qp->remote_ah_attr = attr->ah_attr;
+		rdma_replace_ah_attr(&qp->remote_ah_attr, &attr->ah_attr);
 		qp->s_srate = rdma_ah_get_static_rate(&attr->ah_attr);
 		qp->srate_mbps = ib_rate_to_mbps(qp->s_srate);
 	}
 
 	if (attr_mask & IB_QP_ALT_PATH) {
-		qp->alt_ah_attr = attr->alt_ah_attr;
+		rdma_replace_ah_attr(&qp->alt_ah_attr, &attr->alt_ah_attr);
 		qp->s_alt_pkey_index = attr->alt_pkey_index;
 	}
 
@@ -1462,6 +1462,8 @@ int rvt_destroy_qp(struct ib_qp *ibqp)
 	vfree(qp->s_wq);
 	rdi->driver_f.qp_priv_free(rdi, qp);
 	kfree(qp->s_ack_queue);
+	rdma_destroy_ah_attr(&qp->remote_ah_attr);
+	rdma_destroy_ah_attr(&qp->alt_ah_attr);
 	kfree(qp);
 	return 0;
 }
--- a/include/rdma/ib_verbs.h
+++ b/include/rdma/ib_verbs.h
@@ -4040,6 +4040,11 @@ void rdma_destroy_ah_attr(struct rdma_ah
 void rdma_move_grh_sgid_attr(struct rdma_ah_attr *attr, union ib_gid *dgid,
 			     u32 flow_label, u8 hop_limit, u8 traffic_class,
 			     const struct ib_gid_attr *sgid_attr);
+void rdma_copy_ah_attr(struct rdma_ah_attr *dest,
+		       const struct rdma_ah_attr *src);
+void rdma_replace_ah_attr(struct rdma_ah_attr *old,
+			  const struct rdma_ah_attr *new);
+void rdma_move_ah_attr(struct rdma_ah_attr *dest, struct rdma_ah_attr *src);
 
 /**
  * rdma_ah_find_type - Return address handle type.