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>

diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
index c334f54..75f9aa2 100644 (file)
--- 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 a29f259..a338927 100644 (file)
--- 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 f92e37e..0194de8 100644 (file)
--- 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;
 }