svcrdma: Simplify receive buffer posting

The svcrdma transport provider currently allocates receive buffers
to the RQ through the xpo_release_rqst method. This approach is overly
complicated since it means that the rqstp rq_xprt_ctxt has to be
selectively set based on whether the RPC is going to be processed
immediately or deferred. Instead, just post the receive buffer when
we are certain that we are replying in the send_reply function.

Signed-off-by: Tom Tucker <tom@opengridcomputing.com>

diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
index c22d6b6f2db43d2d8475c742ac66edd047161f86..f3a108a864adc7822cbcaae979254627f43c9e82 100644 (file)
--- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
@@ -457,8 +457,6 @@ static int rdma_read_complete(struct svc_rqst *rqstp,
                ret, rqstp->rq_arg.len, rqstp->rq_arg.head[0].iov_base,
                rqstp->rq_arg.head[0].iov_len);
 
-       /* Indicate that we've consumed an RQ credit */
-       rqstp->rq_xprt_ctxt = rqstp->rq_xprt;
        svc_xprt_received(rqstp->rq_xprt);
        return ret;
 }
@@ -480,13 +478,6 @@ int svc_rdma_recvfrom(struct svc_rqst *rqstp)
 
        dprintk("svcrdma: rqstp=%p\n", rqstp);
 
-       /*
-        * The rq_xprt_ctxt indicates if we've consumed an RQ credit
-        * or not. It is used in the rdma xpo_release_rqst function to
-        * determine whether or not to return an RQ WQE to the RQ.
-        */
-       rqstp->rq_xprt_ctxt = NULL;
-
        spin_lock_bh(&rdma_xprt->sc_read_complete_lock);
        if (!list_empty(&rdma_xprt->sc_read_complete_q)) {
                ctxt = list_entry(rdma_xprt->sc_read_complete_q.next,
@@ -550,9 +541,6 @@ int svc_rdma_recvfrom(struct svc_rqst *rqstp)
                return 0;
        }
 
-       /* Indicate we've consumed an RQ credit */
-       rqstp->rq_xprt_ctxt = rqstp->rq_xprt;
-
        ret = rqstp->rq_arg.head[0].iov_len
                + rqstp->rq_arg.page_len
                + rqstp->rq_arg.tail[0].iov_len;
@@ -569,11 +557,8 @@ int svc_rdma_recvfrom(struct svc_rqst *rqstp)
        return ret;
 
  close_out:
-       if (ctxt) {
+       if (ctxt)
                svc_rdma_put_context(ctxt, 1);
-               /* Indicate we've consumed an RQ credit */
-               rqstp->rq_xprt_ctxt = rqstp->rq_xprt;
-       }
        dprintk("svcrdma: transport %p is closing\n", xprt);
        /*
         * Set the close bit and enqueue it. svc_recv will see the

diff --git a/net/sunrpc/xprtrdma/svc_rdma_sendto.c b/net/sunrpc/xprtrdma/svc_rdma_sendto.c
index 981f190c1b398278b496300a69b733fe2469c922..f61d7bd105fb9a71dbba8b662d2dfa5bd8b6ec9c 100644 (file)
--- a/net/sunrpc/xprtrdma/svc_rdma_sendto.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_sendto.c
@@ -389,6 +389,16 @@ static int send_reply(struct svcxprt_rdma *rdma,
        int page_no;
        int ret;
 
+       /* Post a recv buffer to handle another request. */
+       ret = svc_rdma_post_recv(rdma);
+       if (ret) {
+               printk(KERN_INFO
+                      "svcrdma: could not post a receive buffer, err=%d."
+                      "Closing transport %p.\n", ret, rdma);
+               set_bit(XPT_CLOSE, &rdma->sc_xprt.xpt_flags);
+               return 0;
+       }
+
        /* Prepare the context */
        ctxt->pages[0] = page;
        ctxt->count = 1;

diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c
index af408fc1263403beb37989bff89006fc7d42a669..1e0af2f205e90e2a518949f3dfbdef94187b83a7 100644 (file)
--- a/net/sunrpc/xprtrdma/svc_rdma_transport.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c
@@ -910,27 +910,8 @@ static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt)
        return NULL;
 }
 
-/*
- * Post an RQ WQE to the RQ when the rqst is being released. This
- * effectively returns an RQ credit to the client. The rq_xprt_ctxt
- * will be null if the request is deferred due to an RDMA_READ or the
- * transport had no data ready (EAGAIN). Note that an RPC deferred in
- * svc_process will still return the credit, this is because the data
- * is copied and no longer consume a WQE/WC.
- */
 static void svc_rdma_release_rqst(struct svc_rqst *rqstp)
 {
-       int err;
-       struct svcxprt_rdma *rdma =
-               container_of(rqstp->rq_xprt, struct svcxprt_rdma, sc_xprt);
-       if (rqstp->rq_xprt_ctxt) {
-               BUG_ON(rqstp->rq_xprt_ctxt != rdma);
-               err = svc_rdma_post_recv(rdma);
-               if (err)
-                       dprintk("svcrdma: failed to post an RQ WQE error=%d\n",
-                               err);
-       }
-       rqstp->rq_xprt_ctxt = NULL;
 }
 
 /*