From: Tom Tucker <tom@xxxxxxxxxxxxxxxxxxxxx>
This logic sets the connection parameter that configures the local device
and informs the remote peer how many concurrent incoming RDMA_READ
requests are supported. The original logic didn't really do what was
intended for two reasons:
- The max number supported by the device is typically smaller than
any one factor in the calculation used, and
- The field in the connection parameter structure where the value is
stored is a u8 and always overflows for the default settings.
So what really happens is the value requested for responder resources
is the left over 8 bits from the "desired value". If the desired value
happened to be a multiple of 256, the result was zero and it wouldn't
connect at all.
Given the above and the fact that max_requests is almost always larger
than the max responder resources supported by the adapter, this patch
simplifies this logic and simply requests the max supported by the device,
subject to a reasonable limit.
This bug was found by Jim Schutt at Sandia.
Signed-off-by: Tom Tucker <tom@xxxxxxxxxxxxxxxxxxxxx>
Acked-by: Tom Talpey <talpey@xxxxxxxxxx>
---
net/sunrpc/xprtrdma/verbs.c | 51 ++++++++++++-------------------------------
1 files changed, 14 insertions(+), 37 deletions(-)
diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c
index 39a1652..e3fe905 100644
--- a/net/sunrpc/xprtrdma/verbs.c
+++ b/net/sunrpc/xprtrdma/verbs.c
@@ -705,30 +705,13 @@ rpcrdma_ep_create(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia,
ep->rep_remote_cma.private_data_len = 0;
/* Client offers RDMA Read but does not initiate */
- switch (ia->ri_memreg_strategy) {
- case RPCRDMA_BOUNCEBUFFERS:
+ ep->rep_remote_cma.initiator_depth = 0;
+ if (ia->ri_memreg_strategy == RPCRDMA_BOUNCEBUFFERS)
ep->rep_remote_cma.responder_resources = 0;
- break;
- case RPCRDMA_MTHCAFMR:
- case RPCRDMA_REGISTER:
- case RPCRDMA_FRMR:
- ep->rep_remote_cma.responder_resources = cdata->max_requests *
- (RPCRDMA_MAX_DATA_SEGS / 8);
- break;
- case RPCRDMA_MEMWINDOWS:
- case RPCRDMA_MEMWINDOWS_ASYNC:
-#if RPCRDMA_PERSISTENT_REGISTRATION
- case RPCRDMA_ALLPHYSICAL:
-#endif
- ep->rep_remote_cma.responder_resources = cdata->max_requests *
- (RPCRDMA_MAX_DATA_SEGS / 2);
- break;
- default:
- break;
- }
- if (ep->rep_remote_cma.responder_resources > devattr.max_qp_rd_atom)
+ else if (devattr.max_qp_rd_atom > 32) /* arbitrary but <= 255 */
+ ep->rep_remote_cma.responder_resources = 32;
+ else
ep->rep_remote_cma.responder_resources = devattr.max_qp_rd_atom;
- ep->rep_remote_cma.initiator_depth = 0;
ep->rep_remote_cma.retry_count = 7;
ep->rep_remote_cma.flow_control = 0;
@@ -858,14 +841,6 @@ if (strnicmp(ia->ri_id->device->dma_device->bus->name, "pci", 3) == 0) {
}
}
- /* Theoretically a client initiator_depth > 0 is not needed,
- * but many peers fail to complete the connection unless they
- * == responder_resources! */
- if (ep->rep_remote_cma.initiator_depth !=
- ep->rep_remote_cma.responder_resources)
- ep->rep_remote_cma.initiator_depth =
- ep->rep_remote_cma.responder_resources;
-
ep->rep_connected = 0;
rc = rdma_connect(ia->ri_id, &ep->rep_remote_cma);
@@ -894,14 +869,16 @@ if (strnicmp(ia->ri_id->device->dma_device->bus->name, "pci", 3) == 0) {
if (ep->rep_connected <= 0) {
/* Sometimes, the only way to reliably connect to remote
* CMs is to use same nonzero values for ORD and IRD. */
- ep->rep_remote_cma.initiator_depth =
- ep->rep_remote_cma.responder_resources;
- if (ep->rep_remote_cma.initiator_depth == 0)
- ++ep->rep_remote_cma.initiator_depth;
- if (ep->rep_remote_cma.responder_resources == 0)
- ++ep->rep_remote_cma.responder_resources;
- if (retry_count++ == 0)
+ if (retry_count++ <= RDMA_CONNECT_RETRY_MAX + 1 &&
+ (ep->rep_remote_cma.responder_resources == 0 ||
+ ep->rep_remote_cma.initiator_depth !=
+ ep->rep_remote_cma.responder_resources)) {
+ if (ep->rep_remote_cma.responder_resources == 0)
+ ep->rep_remote_cma.responder_resources = 1;
+ ep->rep_remote_cma.initiator_depth =
+ ep->rep_remote_cma.responder_resources;
goto retry;
+ }
rc = ep->rep_connected;
} else {
dprintk("RPC: %s: connected\n", __func__);
--
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