xprtrdma: Refactor reply handler error handling

Clean up: The error cases in rpcrdma_reply_handler() almost never
execute. Ensure the compiler places them out of the hot path.

No behavior change expected.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Sagi Grimberg <sagig@mellanox.com>
Reviewed-by: Devesh Sharma <devesh.sharma@avagotech.com>
Tested-By: Devesh Sharma <devesh.sharma@avagotech.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

diff --git a/net/sunrpc/xprtrdma/rpc_rdma.c b/net/sunrpc/xprtrdma/rpc_rdma.c
index bc8bd6577467d5d2346b452a3c0d3c65411b3639..60ffa63096dd9b624e1f42b10980b8b45ffa4fce 100644 (file)
--- a/net/sunrpc/xprtrdma/rpc_rdma.c
+++ b/net/sunrpc/xprtrdma/rpc_rdma.c
@@ -741,52 +741,27 @@ rpcrdma_reply_handler(struct rpcrdma_rep *rep)
        unsigned long cwnd;
        u32 credits;
 
-       /* Check status. If bad, signal disconnect and return rep to pool */
-       if (rep->rr_len == ~0U) {
-               rpcrdma_recv_buffer_put(rep);
-               if (r_xprt->rx_ep.rep_connected == 1) {
-                       r_xprt->rx_ep.rep_connected = -EIO;
-                       rpcrdma_conn_func(&r_xprt->rx_ep);
-               }
-               return;
-       }
-       if (rep->rr_len < RPCRDMA_HDRLEN_MIN) {
-               dprintk("RPC:       %s: short/invalid reply\n", __func__);
-               goto repost;
-       }
+       dprintk("RPC:       %s: incoming rep %p\n", __func__, rep);
+
+       if (rep->rr_len == RPCRDMA_BAD_LEN)
+               goto out_badstatus;
+       if (rep->rr_len < RPCRDMA_HDRLEN_MIN)
+               goto out_shortreply;
+
        headerp = rdmab_to_msg(rep->rr_rdmabuf);
-       if (headerp->rm_vers != rpcrdma_version) {
-               dprintk("RPC:       %s: invalid version %d\n",
-                       __func__, be32_to_cpu(headerp->rm_vers));
-               goto repost;
-       }
+       if (headerp->rm_vers != rpcrdma_version)
+               goto out_badversion;
 
        /* Get XID and try for a match. */
        spin_lock(&xprt->transport_lock);
        rqst = xprt_lookup_rqst(xprt, headerp->rm_xid);
-       if (rqst == NULL) {
-               spin_unlock(&xprt->transport_lock);
-               dprintk("RPC:       %s: reply 0x%p failed "
-                       "to match any request xid 0x%08x len %d\n",
-                       __func__, rep, be32_to_cpu(headerp->rm_xid),
-                       rep->rr_len);
-repost:
-               r_xprt->rx_stats.bad_reply_count++;
-               if (rpcrdma_ep_post_recv(&r_xprt->rx_ia, &r_xprt->rx_ep, rep))
-                       rpcrdma_recv_buffer_put(rep);
-
-               return;
-       }
+       if (!rqst)
+               goto out_nomatch;
 
        /* get request object */
        req = rpcr_to_rdmar(rqst);
-       if (req->rl_reply) {
-               spin_unlock(&xprt->transport_lock);
-               dprintk("RPC:       %s: duplicate reply 0x%p to RPC "
-                       "request 0x%p: xid 0x%08x\n", __func__, rep, req,
-                       be32_to_cpu(headerp->rm_xid));
-               goto repost;
-       }
+       if (req->rl_reply)
+               goto out_duplicate;
 
        dprintk("RPC:       %s: reply 0x%p completes request 0x%p\n"
                "                   RPC request 0x%p xid 0x%08x\n",
@@ -883,8 +858,44 @@ badheader:
        if (xprt->cwnd > cwnd)
                xprt_release_rqst_cong(rqst->rq_task);
 
+       xprt_complete_rqst(rqst->rq_task, status);
+       spin_unlock(&xprt->transport_lock);
        dprintk("RPC:       %s: xprt_complete_rqst(0x%p, 0x%p, %d)\n",
                        __func__, xprt, rqst, status);
-       xprt_complete_rqst(rqst->rq_task, status);
+       return;
+
+out_badstatus:
+       rpcrdma_recv_buffer_put(rep);
+       if (r_xprt->rx_ep.rep_connected == 1) {
+               r_xprt->rx_ep.rep_connected = -EIO;
+               rpcrdma_conn_func(&r_xprt->rx_ep);
+       }
+       return;
+
+out_shortreply:
+       dprintk("RPC:       %s: short/invalid reply\n", __func__);
+       goto repost;
+
+out_badversion:
+       dprintk("RPC:       %s: invalid version %d\n",
+               __func__, be32_to_cpu(headerp->rm_vers));
+       goto repost;
+
+out_nomatch:
+       spin_unlock(&xprt->transport_lock);
+       dprintk("RPC:       %s: no match for incoming xid 0x%08x len %d\n",
+               __func__, be32_to_cpu(headerp->rm_xid),
+               rep->rr_len);
+       goto repost;
+
+out_duplicate:
        spin_unlock(&xprt->transport_lock);
+       dprintk("RPC:       %s: "
+               "duplicate reply %p to RPC request %p: xid 0x%08x\n",
+               __func__, rep, req, be32_to_cpu(headerp->rm_xid));
+
+repost:
+       r_xprt->rx_stats.bad_reply_count++;
+       if (rpcrdma_ep_post_recv(&r_xprt->rx_ia, &r_xprt->rx_ep, rep))
+               rpcrdma_recv_buffer_put(rep);
 }

diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c
index 6661b1b95758cf4918008c0c04181279bfd46e06..a60b4c4d9886a773ed0026a30b3ad9b94691449d 100644 (file)
--- a/net/sunrpc/xprtrdma/verbs.c
+++ b/net/sunrpc/xprtrdma/verbs.c
@@ -225,7 +225,7 @@ out_fail:
        if (wc->status != IB_WC_WR_FLUSH_ERR)
                pr_err("RPC:       %s: rep %p: %s\n",
                       __func__, rep, ib_wc_status_msg(wc->status));
-       rep->rr_len = ~0U;
+       rep->rr_len = RPCRDMA_BAD_LEN;
        goto out_schedule;
 }
 

diff --git a/net/sunrpc/xprtrdma/xprt_rdma.h b/net/sunrpc/xprtrdma/xprt_rdma.h
index 42c8d44a175b6a2a54edbd53ee0e3e14594ba28d..a13508bbe4c40466752f2cd391be2444ec1ced5c 100644 (file)
--- a/net/sunrpc/xprtrdma/xprt_rdma.h
+++ b/net/sunrpc/xprtrdma/xprt_rdma.h
@@ -168,6 +168,8 @@ struct rpcrdma_rep {
        struct rpcrdma_regbuf   *rr_rdmabuf;
 };
 
+#define RPCRDMA_BAD_LEN                (~0U)
+
 /*
  * struct rpcrdma_mw - external memory region metadata
  *