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>

1 files changed, 3 insertions, 1 deletions

diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
index c334f54..75f9aa2 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);
 	}