This patch shows it is possible to replace the current
method used by rdma_rxe to handle UD transport where
user space creates and then passes an rxe_av *av to the
kernel driver as part of each rxe_send_wqe.
Here user space passes the handle created by the call to
ibv_create_ah in the send wqe. The kernel driver uses that
handle to get a pointer to the 'real' rxe_av that was
created in the kernel by the create ah verb.
To do this requires executing code in the driver that mimics
what is done in rdma_core to convert handles to objects.
This is not ideal but gets the job done. It would probably be
better for rdma_core to provide a service that can do this
for software drivers that have to do this.
The alternative (used by the MW code) is to create a driver
private index and pass that back from the create verb to
user space and then have user space use that in the send wqe.
I would like to avoid replicating work already being done by
rdma core by using the handle that already exists. I don't
know the relative performance of the lookup in rdma_core and
the red black tree used by rxe currently.
There is a matching change to provider/rxe.
Signed-off-by: Bob Pearson <rpearson@xxxxxxx>
---
diff --git a/drivers/infiniband/core/rdma_core.c b/drivers/infiniband/core/rdma_core.c
index ffe11b03724c..faa70c4f14bb 100644
--- a/drivers/infiniband/core/rdma_core.c
+++ b/drivers/infiniband/core/rdma_core.c
@@ -425,6 +425,7 @@ struct ib_uobject *rdma_lookup_get_uobject(const struct uverbs_api_object *obj,
uverbs_uobject_put(uobj);
return ERR_PTR(ret);
}
+EXPORT_SYMBOL(rdma_lookup_get_uobject);
static struct ib_uobject *
alloc_begin_idr_uobject(const struct uverbs_api_object *obj,
@@ -726,6 +727,7 @@ void rdma_lookup_put_uobject(struct ib_uobject *uobj,
/* Pairs with the kref obtained by type->lookup_get */
uverbs_uobject_put(uobj);
}
+EXPORT_SYMBOL(rdma_lookup_put_uobject);
void setup_ufile_idr_uobject(struct ib_uverbs_file *ufile)
{
diff --git a/drivers/infiniband/sw/rxe/rxe_av.c b/drivers/infiniband/sw/rxe/rxe_av.c
index 38021e2c8688..db83e1cde38e 100644
--- a/drivers/infiniband/sw/rxe/rxe_av.c
+++ b/drivers/infiniband/sw/rxe/rxe_av.c
@@ -6,6 +6,8 @@
#include "rxe.h"
#include "rxe_loc.h"
+#include "../../core/uverbs.h"
+#include "../../core/rdma_core.h"
void rxe_init_av(struct rdma_ah_attr *attr, struct rxe_av *av)
{
@@ -72,13 +74,50 @@ void rxe_av_fill_ip_info(struct rxe_av *av, struct rdma_ah_attr *attr)
av->network_type = rdma_gid_attr_network_type(sgid_attr);
}
+static struct ib_ah *get_ah_from_handle(struct rxe_qp *qp, u32 handle)
+{
+ struct ib_uverbs_file *ufile;
+ struct uverbs_api *uapi;
+ const struct uverbs_api_object *type;
+ struct ib_uobject *uobj;
+
+ ufile = qp->ibqp.uobject->uevent.uobject.ufile;
+ uapi = ufile->device->uapi;
+ type = uapi_get_object(uapi, UVERBS_OBJECT_AH);
+ if (IS_ERR(type))
+ return NULL;
+ uobj = rdma_lookup_get_uobject(type, ufile, (s64)handle,
+ UVERBS_LOOKUP_READ, NULL);
+ if (IS_ERR(uobj)) {
+ pr_warn("unable to lookup ah handle\n");
+ return NULL;
+ }
+
+ rdma_lookup_put_uobject(uobj, UVERBS_LOOKUP_READ);
+ return uobj->object;
+}
+
struct rxe_av *rxe_get_av(struct rxe_pkt_info *pkt)
{
- if (!pkt || !pkt->qp)
+ struct rxe_qp *qp = pkt->qp;
+ struct rxe_send_wqe *wqe = pkt->wqe;
+ u32 handle;
+ struct ib_ah *ibah;
+ struct rxe_ah *ah;
+
+ if (!pkt || !qp)
return NULL;
- if (qp_type(pkt->qp) == IB_QPT_RC || qp_type(pkt->qp) == IB_QPT_UC)
- return &pkt->qp->pri_av;
+ if (qp_type(qp) == IB_QPT_RC || qp_type(qp) == IB_QPT_UC)
+ return &qp->pri_av;
+
+ if (qp->is_user) {
+ handle = wqe->wr.wr.ud.ah_handle;
+ ibah = get_ah_from_handle(qp, handle);
+ } else {
+ ibah = wqe->wr.wr.ud.ah;
+ }
- return (pkt->wqe) ? &pkt->wqe->av : NULL;
+ ah = to_rah(ibah);
+ return &ah->av;
}
diff --git a/drivers/infiniband/sw/rxe/rxe_req.c b/drivers/infiniband/sw/rxe/rxe_req.c
index d4917646641a..2a887dca9a28 100644
--- a/drivers/infiniband/sw/rxe/rxe_req.c
+++ b/drivers/infiniband/sw/rxe/rxe_req.c
@@ -380,12 +380,16 @@ static struct sk_buff *init_req_packet(struct rxe_qp *qp,
/* init skb */
av = rxe_get_av(pkt);
+ if (!av) {
+ pr_warn("unable to get av\n");
+ return NULL;
+ }
skb = rxe_init_packet(rxe, av, paylen, pkt);
if (unlikely(!skb))
return NULL;
/* init bth */
- solicited = (ibwr->send_flags & IB_SEND_SOLICITED) &&
+ solicited = (ibwr->send_flags & IB_SEND_SOLICITED) &&
(pkt->mask & RXE_END_MASK) &&
((pkt->mask & (RXE_SEND_MASK)) ||
(pkt->mask & (RXE_WRITE_MASK | RXE_IMMDT_MASK)) ==
diff --git a/drivers/infiniband/sw/rxe/rxe_verbs.c b/drivers/infiniband/sw/rxe/rxe_verbs.c
index 0a7d7c55d8d6..4d4ded90f793 100644
--- a/drivers/infiniband/sw/rxe/rxe_verbs.c
+++ b/drivers/infiniband/sw/rxe/rxe_verbs.c
@@ -506,6 +506,7 @@ static void init_send_wr(struct rxe_qp *qp, struct rxe_send_wr *wr,
if (qp_type(qp) == IB_QPT_UD ||
qp_type(qp) == IB_QPT_SMI ||
qp_type(qp) == IB_QPT_GSI) {
+ wr->wr.ud.ah = ud_wr(ibwr)->ah;
wr->wr.ud.remote_qpn = ud_wr(ibwr)->remote_qpn;
wr->wr.ud.remote_qkey = ud_wr(ibwr)->remote_qkey;
if (qp_type(qp) == IB_QPT_GSI)
@@ -562,11 +563,6 @@ static int init_send_wqe(struct rxe_qp *qp, const struct ib_send_wr *ibwr,
init_send_wr(qp, &wqe->wr, ibwr);
- if (qp_type(qp) == IB_QPT_UD ||
- qp_type(qp) == IB_QPT_SMI ||
- qp_type(qp) == IB_QPT_GSI)
- memcpy(&wqe->av, &to_rah(ud_wr(ibwr)->ah)->av, sizeof(wqe->av));
-
if (unlikely(ibwr->send_flags & IB_SEND_INLINE)) {
p = wqe->dma.inline_data;
diff --git a/include/uapi/rdma/rdma_user_rxe.h b/include/uapi/rdma/rdma_user_rxe.h
index d8f2e0e46dab..d57271451052 100644
--- a/include/uapi/rdma/rdma_user_rxe.h
+++ b/include/uapi/rdma/rdma_user_rxe.h
@@ -89,6 +89,10 @@ struct rxe_send_wr {
__u32 reserved;
} atomic;
struct {
+ union {
+ __aligned_u64 ah_handle;
+ struct ib_ah *ah;
+ };
__u32 remote_qpn;
__u32 remote_qkey;
__u16 pkey_index;
@@ -132,7 +136,6 @@ struct rxe_dma_info {
struct rxe_send_wqe {
struct rxe_send_wr wr;
- struct rxe_av av;
__u32 status;
__u32 state;
__aligned_u64 iova;
--
2.25.1
