svcrdma: Consult max_qp_init_rd_atom when accepting connections

The target needs to return the lesser of the client's Inbound RDMA
Read Queue Depth (IRD), provided in the connection parameters, and
the local device's Outbound RDMA Read Queue Depth (ORD). The latter
limit is max_qp_init_rd_atom, not max_qp_rd_atom.

The svcrdma_ord value caps the ORD value for iWARP transports, which
do not exchange ORD/IRD values at connection time. Since no other
Linux kernel RDMA-enabled storage target sees fit to provide this
cap, I'm removing it here too.

initiator_depth is a u8, so ensure the computed ORD value does not
overflow that field.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

diff --git a/include/linux/sunrpc/svc_rdma.h b/include/linux/sunrpc/svc_rdma.h
index 4b731b046bcde187630d02b16ec19f33dd405afd..7337e1221590c235cc9a4b8bbdbc9fb0e1299c5d 100644 (file)
--- a/include/linux/sunrpc/svc_rdma.h
+++ b/include/linux/sunrpc/svc_rdma.h
@@ -132,9 +132,6 @@ struct svcxprt_rdma {
 #define RDMAXPRT_CONN_PENDING  3
 
 #define RPCRDMA_LISTEN_BACKLOG  10
-/* The default ORD value is based on two outstanding full-size writes with a
- * page size of 4k, or 32k * 2 ops / 4k = 16 outstanding RDMA_READ.  */
-#define RPCRDMA_ORD             (64/4)
 #define RPCRDMA_MAX_REQUESTS    32
 
 /* Typical ULP usage of BC requests is NFSv4.1 backchannel. Our

diff --git a/net/sunrpc/xprtrdma/svc_rdma.c b/net/sunrpc/xprtrdma/svc_rdma.c
index a4a8f6989ee747a1a5046e1e5cff92a0ca167775..dd8a431dc2ae155304a9b3bd3aa8d1132b9dccc7 100644 (file)
--- a/net/sunrpc/xprtrdma/svc_rdma.c
+++ b/net/sunrpc/xprtrdma/svc_rdma.c
@@ -51,9 +51,9 @@
 #define RPCDBG_FACILITY        RPCDBG_SVCXPRT
 
 /* RPC/RDMA parameters */
-unsigned int svcrdma_ord = RPCRDMA_ORD;
+unsigned int svcrdma_ord = 16; /* historical default */
 static unsigned int min_ord = 1;
-static unsigned int max_ord = 4096;
+static unsigned int max_ord = 255;
 unsigned int svcrdma_max_requests = RPCRDMA_MAX_REQUESTS;
 unsigned int svcrdma_max_bc_requests = RPCRDMA_MAX_BC_REQUESTS;
 static unsigned int min_max_requests = 4;

diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c
index 135ae175ca8eb94531d967b32e0f2e389acb306d..7b2f4d3a25437156ef704be9679c450bb8e621b8 100644 (file)
--- a/net/sunrpc/xprtrdma/svc_rdma_transport.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c
@@ -762,13 +762,6 @@ static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt)
        if (!svc_rdma_prealloc_ctxts(newxprt))
                goto errout;
 
-       /*
-        * Limit ORD based on client limit, local device limit, and
-        * configured svcrdma limit.
-        */
-       newxprt->sc_ord = min_t(size_t, dev->attrs.max_qp_rd_atom, newxprt->sc_ord);
-       newxprt->sc_ord = min_t(size_t, svcrdma_ord, newxprt->sc_ord);
-
        newxprt->sc_pd = ib_alloc_pd(dev, 0);
        if (IS_ERR(newxprt->sc_pd)) {
                dprintk("svcrdma: error creating PD for connect request\n");
@@ -843,15 +836,18 @@ static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt)
        set_bit(RDMAXPRT_CONN_PENDING, &newxprt->sc_flags);
        memset(&conn_param, 0, sizeof conn_param);
        conn_param.responder_resources = 0;
-       conn_param.initiator_depth = newxprt->sc_ord;
+       conn_param.initiator_depth = min_t(int, newxprt->sc_ord,
+                                          dev->attrs.max_qp_init_rd_atom);
+       if (!conn_param.initiator_depth) {
+               dprintk("svcrdma: invalid ORD setting\n");
+               ret = -EINVAL;
+               goto errout;
+       }
        conn_param.private_data = &pmsg;
        conn_param.private_data_len = sizeof(pmsg);
        ret = rdma_accept(newxprt->sc_cm_id, &conn_param);
-       if (ret) {
-               dprintk("svcrdma: failed to accept new connection, ret=%d\n",
-                      ret);
+       if (ret)
                goto errout;
-       }
 
        dprintk("svcrdma: new connection %p accepted:\n", newxprt);
        sap = (struct sockaddr *)&newxprt->sc_cm_id->route.addr.src_addr;
@@ -862,7 +858,7 @@ static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt)
        dprintk("    sq_depth        : %d\n", newxprt->sc_sq_depth);
        dprintk("    rdma_rw_ctxs    : %d\n", ctxts);
        dprintk("    max_requests    : %d\n", newxprt->sc_max_requests);
-       dprintk("    ord             : %d\n", newxprt->sc_ord);
+       dprintk("    ord             : %d\n", conn_param.initiator_depth);
 
        return &newxprt->sc_xprt;