[v1,6/6] svcrdma: Clean up dto_q critical section in svc_rdma_recvfrom()

Commit Message

Chuck Lever III March 29, 2021, 2:40 p.m. UTC

This, to me, seems less cluttered and less redundant. I was hoping
it could help reduce lock contention on the dto_q lock by reducing
the size of the critical section, but alas, the only improvement is
readability.

Signed-off-by: Chuck Lever <[e-mail]>
---
 net/sunrpc/xprtrdma/svc_rdma_recvfrom.c |   16 +++++++---------
 1 file changed, 7 insertions(+), 9 deletions(-)

Patch

diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
index 357e3ae01991..1cf0b04b632a 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
@@ -794,22 +794,20 @@  int svc_rdma_recvfrom(struct svc_rqst *rqstp)
 
 	rqstp->rq_xprt_ctxt = NULL;
 
+	ctxt = NULL;
 	spin_lock(&rdma_xprt->sc_rq_dto_lock);
 	ctxt = svc_rdma_next_recv_ctxt(&rdma_xprt->sc_rq_dto_q);
-	if (!ctxt) {
+	if (ctxt)
+		list_del(&ctxt->rc_list);
+	else
 		/* No new incoming requests, terminate the loop */
 		clear_bit(XPT_DATA, &xprt->xpt_flags);
-		spin_unlock(&rdma_xprt->sc_rq_dto_lock);
-		svc_xprt_received(xprt);
-		return 0;
-	}
-	list_del(&ctxt->rc_list);
 	spin_unlock(&rdma_xprt->sc_rq_dto_lock);
-	percpu_counter_inc(&svcrdma_stat_recv);
-
-	/* Start receiving the next incoming message */
 	svc_xprt_received(xprt);
+	if (!ctxt)
+		return 0;
 
+	percpu_counter_inc(&svcrdma_stat_recv);
 	ib_dma_sync_single_for_cpu(rdma_xprt->sc_pd->device,
 				   ctxt->rc_recv_sge.addr, ctxt->rc_byte_len,
 				   DMA_FROM_DEVICE);