For FRWR, the computation of max_send_wr is split between
frwr_op_open and rpcrdma_ep_create, which makes it difficult to tell
that the max_send_wr result is currently incorrect if frwr_op_open
has to reduce the credit limit to accommodate a small max_qp_wr.
This is a problem now that extra WRs are needed for backchannel
operations and a drain CQE.
So, refactor the computation so that it is all done in ->ro_open,
and fix the FRWR version of this computation so that it
accommodates HCAs with small max_qp_wr correctly.
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
---
net/sunrpc/xprtrdma/fmr_ops.c | 22 ++++++++++++++++++++++
net/sunrpc/xprtrdma/frwr_ops.c | 30 ++++++++++++++++++++++++++----
net/sunrpc/xprtrdma/verbs.c | 24 ++++--------------------
3 files changed, 52 insertions(+), 24 deletions(-)
diff --git a/net/sunrpc/xprtrdma/fmr_ops.c b/net/sunrpc/xprtrdma/fmr_ops.c
index f2f6395..0815f9e 100644
--- a/net/sunrpc/xprtrdma/fmr_ops.c
+++ b/net/sunrpc/xprtrdma/fmr_ops.c
@@ -156,10 +156,32 @@ enum {
fmr_op_release_mr(mr);
}
+/* On success, sets:
+ * ep->rep_attr.cap.max_send_wr
+ * ep->rep_attr.cap.max_recv_wr
+ * cdata->max_requests
+ * ia->ri_max_segs
+ */
static int
fmr_op_open(struct rpcrdma_ia *ia, struct rpcrdma_ep *ep,
struct rpcrdma_create_data_internal *cdata)
{
+ int max_qp_wr;
+
+ max_qp_wr = ia->ri_device->attrs.max_qp_wr;
+ max_qp_wr -= RPCRDMA_BACKWARD_WRS;
+ max_qp_wr -= 1;
+ if (max_qp_wr < RPCRDMA_MIN_SLOT_TABLE)
+ return -ENOMEM;
+ if (cdata->max_requests > max_qp_wr)
+ cdata->max_requests = max_qp_wr;
+ ep->rep_attr.cap.max_send_wr = cdata->max_requests;
+ ep->rep_attr.cap.max_send_wr += RPCRDMA_BACKWARD_WRS;
+ ep->rep_attr.cap.max_send_wr += 1; /* for ib_drain_sq */
+ ep->rep_attr.cap.max_recv_wr = cdata->max_requests;
+ ep->rep_attr.cap.max_recv_wr += RPCRDMA_BACKWARD_WRS;
+ ep->rep_attr.cap.max_recv_wr += 1; /* for ib_drain_rq */
+
ia->ri_max_segs = max_t(unsigned int, 1, RPCRDMA_MAX_DATA_SEGS /
RPCRDMA_MAX_FMR_SGES);
return 0;
diff --git a/net/sunrpc/xprtrdma/frwr_ops.c b/net/sunrpc/xprtrdma/frwr_ops.c
index c59c5c7..cf5095d6 100644
--- a/net/sunrpc/xprtrdma/frwr_ops.c
+++ b/net/sunrpc/xprtrdma/frwr_ops.c
@@ -202,12 +202,22 @@
frwr_op_release_mr(mr);
}
+/* On success, sets:
+ * ep->rep_attr.cap.max_send_wr
+ * ep->rep_attr.cap.max_recv_wr
+ * cdata->max_requests
+ * ia->ri_max_segs
+ *
+ * And these FRWR-related fields:
+ * ia->ri_max_frwr_depth
+ * ia->ri_mrtype
+ */
static int
frwr_op_open(struct rpcrdma_ia *ia, struct rpcrdma_ep *ep,
struct rpcrdma_create_data_internal *cdata)
{
struct ib_device_attr *attrs = &ia->ri_device->attrs;
- int depth, delta;
+ int max_qp_wr, depth, delta;
ia->ri_mrtype = IB_MR_TYPE_MEM_REG;
if (attrs->device_cap_flags & IB_DEVICE_SG_GAPS_REG)
@@ -241,14 +251,26 @@
} while (delta > 0);
}
- ep->rep_attr.cap.max_send_wr *= depth;
- if (ep->rep_attr.cap.max_send_wr > attrs->max_qp_wr) {
- cdata->max_requests = attrs->max_qp_wr / depth;
+ max_qp_wr = ia->ri_device->attrs.max_qp_wr;
+ max_qp_wr -= RPCRDMA_BACKWARD_WRS;
+ max_qp_wr -= 1;
+ if (max_qp_wr < RPCRDMA_MIN_SLOT_TABLE)
+ return -ENOMEM;
+ if (cdata->max_requests > max_qp_wr)
+ cdata->max_requests = max_qp_wr;
+ ep->rep_attr.cap.max_send_wr = cdata->max_requests * depth;
+ if (ep->rep_attr.cap.max_send_wr > max_qp_wr) {
+ cdata->max_requests = max_qp_wr / depth;
if (!cdata->max_requests)
return -EINVAL;
ep->rep_attr.cap.max_send_wr = cdata->max_requests *
depth;
}
+ ep->rep_attr.cap.max_send_wr += RPCRDMA_BACKWARD_WRS;
+ ep->rep_attr.cap.max_send_wr += 1; /* for ib_drain_sq */
+ ep->rep_attr.cap.max_recv_wr = cdata->max_requests;
+ ep->rep_attr.cap.max_recv_wr += RPCRDMA_BACKWARD_WRS;
+ ep->rep_attr.cap.max_recv_wr += 1; /* for ib_drain_rq */
ia->ri_max_segs = max_t(unsigned int, 1, RPCRDMA_MAX_DATA_SEGS /
ia->ri_max_frwr_depth);
diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c
index 817a692..581d0ae 100644
--- a/net/sunrpc/xprtrdma/verbs.c
+++ b/net/sunrpc/xprtrdma/verbs.c
@@ -501,8 +501,8 @@
struct rpcrdma_create_data_internal *cdata)
{
struct rpcrdma_connect_private *pmsg = &ep->rep_cm_private;
- unsigned int max_qp_wr, max_sge;
struct ib_cq *sendcq, *recvcq;
+ unsigned int max_sge;
int rc;
max_sge = min_t(unsigned int, ia->ri_device->attrs.max_sge,
@@ -513,29 +513,13 @@
}
ia->ri_max_send_sges = max_sge;
- if (ia->ri_device->attrs.max_qp_wr <= RPCRDMA_BACKWARD_WRS) {
- dprintk("RPC: %s: insufficient wqe's available\n",
- __func__);
- return -ENOMEM;
- }
- max_qp_wr = ia->ri_device->attrs.max_qp_wr - RPCRDMA_BACKWARD_WRS - 1;
-
- /* check provider's send/recv wr limits */
- if (cdata->max_requests > max_qp_wr)
- cdata->max_requests = max_qp_wr;
+ rc = ia->ri_ops->ro_open(ia, ep, cdata);
+ if (rc)
+ return rc;
ep->rep_attr.event_handler = rpcrdma_qp_async_error_upcall;
ep->rep_attr.qp_context = ep;
ep->rep_attr.srq = NULL;
- ep->rep_attr.cap.max_send_wr = cdata->max_requests;
- ep->rep_attr.cap.max_send_wr += RPCRDMA_BACKWARD_WRS;
- ep->rep_attr.cap.max_send_wr += 1; /* drain cqe */
- rc = ia->ri_ops->ro_open(ia, ep, cdata);
- if (rc)
- return rc;
- ep->rep_attr.cap.max_recv_wr = cdata->max_requests;
- ep->rep_attr.cap.max_recv_wr += RPCRDMA_BACKWARD_WRS;
- ep->rep_attr.cap.max_recv_wr += 1; /* drain cqe */
ep->rep_attr.cap.max_send_sge = max_sge;
ep->rep_attr.cap.max_recv_sge = 1;
ep->rep_attr.cap.max_inline_data = 0;
--
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