From: Tom Tucker <tom@opengridcomputing.com>
Date: Tue, 6 May 2008 16:49:05 +0000 (-0500)
Subject: svcrdma: Shrink scope of spinlock on RQ CQ
X-Git-Tag: v2.6.26-rc4~90^2^2~9
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=47698e083e40bbd3ef87f5561390ae33abb13cd0;p=linux-2.6

svcrdma: Shrink scope of spinlock on RQ CQ

The rq_cq_reap function is only called from the dto_tasklet. The
only resource shared with other threads is the sc_rq_dto_q. Move the
spin lock to protect only this list.

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

diff --git a/net/sunrpc/xprtrdma/svc_rdma_transport.c b/net/sunrpc/xprtrdma/svc_rdma_transport.c
index 817cf4de74..78303f0fad 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_transport.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_transport.c
@@ -292,7 +292,6 @@ static void rq_cq_reap(struct svcxprt_rdma *xprt)
 	ib_req_notify_cq(xprt->sc_rq_cq, IB_CQ_NEXT_COMP);
 	atomic_inc(&rdma_stat_rq_poll);
 
-	spin_lock_bh(&xprt->sc_rq_dto_lock);
 	while ((ret = ib_poll_cq(xprt->sc_rq_cq, 1, &wc)) > 0) {
 		ctxt = (struct svc_rdma_op_ctxt *)(unsigned long)wc.wr_id;
 		ctxt->wc_status = wc.status;
@@ -303,9 +302,10 @@ static void rq_cq_reap(struct svcxprt_rdma *xprt)
 			svc_rdma_put_context(ctxt, 1);
 			continue;
 		}
+		spin_lock_bh(&xprt->sc_rq_dto_lock);
 		list_add_tail(&ctxt->dto_q, &xprt->sc_rq_dto_q);
+		spin_unlock_bh(&xprt->sc_rq_dto_lock);
 	}
-	spin_unlock_bh(&xprt->sc_rq_dto_lock);
 
 	if (ctxt)
 		atomic_inc(&rdma_stat_rq_prod);