sunrpc: centralise most calls to svc_xprt_received

svc_xprt_received must be called when ->xpo_recvfrom has finished
receiving a message, so that the XPT_BUSY flag will be cleared and
if necessary, requeued for further work.

This call is currently made in each ->xpo_recvfrom function, often
from multiple different points.  In each case it is the earliest point
on a particular path where it is known that the protection provided by
XPT_BUSY is no longer needed.

However there are (still) some error paths which do not call
svc_xprt_received, and requiring each ->xpo_recvfrom to make the call
does not encourage robustness.

So: move the svc_xprt_received call to be made just after the
call to ->xpo_recvfrom(), and move it of the various ->xpo_recvfrom
methods.

This means that it may not be called at the earliest possible instant,
but this is unlikely to be a measurable performance issue.

Note that there are still other calls to svc_xprt_received as it is
also needed when an xprt is newly created.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

3 files changed, 4 insertions, 18 deletions

diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
index c334f5413c60..75f9aa2eb089 100644
--- a/net/sunrpc/svc_xprt.c
+++ b/net/sunrpc/svc_xprt.c
@@ -743,8 +743,10 @@ int svc_recv(struct svc_rqst *rqstp, long timeout)
                 if (rqstp->rq_deferred) {
                         svc_xprt_received(xprt);
                         len = svc_deferred_recv(rqstp);
-                } else
+                } else {
                         len = xprt->xpt_ops->xpo_recvfrom(rqstp);
+                        svc_xprt_received(xprt);
+                }
                 dprintk("svc: got len=%d\n", len);
         }
 
diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c
index a29f259204e6..a33892733643 100644
--- a/net/sunrpc/svcsock.c
+++ b/net/sunrpc/svcsock.c
@@ -547,7 +547,6 @@ static int svc_udp_recvfrom(struct svc_rqst *rqstp)
                         dprintk("svc: recvfrom returned error %d\n", -err);
                         set_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags);
                 }
-                svc_xprt_received(&svsk->sk_xprt);
                 return -EAGAIN;
         }
         len = svc_addr_len(svc_addr(rqstp));
@@ -562,11 +561,6 @@ static int svc_udp_recvfrom(struct svc_rqst *rqstp)
         svsk->sk_sk->sk_stamp = skb->tstamp;
         set_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags); /* there may be more data... */
 
-        /*
-         * Maybe more packets - kick another thread ASAP.
-         */
-        svc_xprt_received(&svsk->sk_xprt);
-
         len  = skb->len - sizeof(struct udphdr);
         rqstp->rq_arg.len = len;
 
@@ -917,7 +911,6 @@ static int svc_tcp_recv_record(struct svc_sock *svsk, struct svc_rqst *rqstp)
                 if (len < want) {
                         dprintk("svc: short recvfrom while reading record "
                                 "length (%d of %d)\n", len, want);
-                        svc_xprt_received(&svsk->sk_xprt);
                         goto err_again; /* record header not complete */
                 }
 
@@ -953,7 +946,6 @@ static int svc_tcp_recv_record(struct svc_sock *svsk, struct svc_rqst *rqstp)
         if (len < svsk->sk_reclen) {
                 dprintk("svc: incomplete TCP record (%d of %d)\n",
                         len, svsk->sk_reclen);
-                svc_xprt_received(&svsk->sk_xprt);
                 goto err_again; /* record not complete */
         }
         len = svsk->sk_reclen;
@@ -961,14 +953,11 @@ static int svc_tcp_recv_record(struct svc_sock *svsk, struct svc_rqst *rqstp)
 
         return len;
  error:
-        if (len == -EAGAIN) {
+        if (len == -EAGAIN)
                 dprintk("RPC: TCP recv_record got EAGAIN\n");
-                svc_xprt_received(&svsk->sk_xprt);
-        }
         return len;
  err_delete:
         set_bit(XPT_CLOSE, &svsk->sk_xprt.xpt_flags);
-        svc_xprt_received(&svsk->sk_xprt);
  err_again:
         return -EAGAIN;
 }
@@ -1110,7 +1099,6 @@ out:
         svsk->sk_tcplen = 0;
 
         svc_xprt_copy_addrs(rqstp, &svsk->sk_xprt);
-        svc_xprt_received(&svsk->sk_xprt);
         if (serv->sv_stats)
                 serv->sv_stats->nettcpcnt++;
 
@@ -1119,7 +1107,6 @@ out:
 err_again:
         if (len == -EAGAIN) {
                 dprintk("RPC: TCP recvfrom got EAGAIN\n");
-                svc_xprt_received(&svsk->sk_xprt);
                 return len;
         }
 error:
diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
index f92e37eb413c..0194de814933 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
@@ -566,7 +566,6 @@ 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);
 
-        svc_xprt_received(rqstp->rq_xprt);
         return ret;
 }
 
@@ -665,7 +664,6 @@ int svc_rdma_recvfrom(struct svc_rqst *rqstp)
                 rqstp->rq_arg.head[0].iov_len);
         rqstp->rq_prot = IPPROTO_MAX;
         svc_xprt_copy_addrs(rqstp, xprt);
-        svc_xprt_received(xprt);
         return ret;
 
  close_out:
@@ -678,6 +676,5 @@ int svc_rdma_recvfrom(struct svc_rqst *rqstp)
          */
         set_bit(XPT_CLOSE, &xprt->xpt_flags);
 defer:
-        svc_xprt_received(xprt);
         return 0;
 }