From: Trond Myklebust <trond.myklebust@hammerspace.com>
Date: Mon, 15 Jul 2019 15:12:08 -0400
Subject: [PATCH] SUNRPC: Replace division by multiplication in calculation of
 queue length
Git-commit: 3cf7292280d5e484747a5f0ee4b62327b037344c
Patch-mainline: v5.3
References: bnc#1192729

When checking whether or not a particular xprt queue length is shorter
than the average queue length for all xprts, prefer to use multiplication
rather than division for performance reasons.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Acked-by: NeilBrown <neilb@suse.com>

---
 net/sunrpc/xprtmultipath.c |    5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

--- a/net/sunrpc/xprtmultipath.c
+++ b/net/sunrpc/xprtmultipath.c
@@ -321,7 +321,6 @@ struct rpc_xprt *xprt_iter_next_entry_ro
 	struct rpc_xprt *xprt;
 	unsigned long xprt_queuelen;
 	unsigned long xps_queuelen;
-	unsigned long xps_avglen;
 
 	do {
 		xprt = xprt_iter_next_entry_multiple(xpi,
@@ -332,8 +331,8 @@ struct rpc_xprt *xprt_iter_next_entry_ro
 		if (xprt_queuelen <= 2)
 			break;
 		xps_queuelen = atomic_long_read(&xps->xps_queuelen);
-		xps_avglen = DIV_ROUND_UP(xps_queuelen, xps->xps_nactive);
-	} while (xprt_queuelen > xps_avglen);
+		/* Exit loop if xprt_queuelen <= average queue length */
+	} while (xprt_queuelen * READ_ONCE(xps->xps_nactive) > xps_queuelen);
 	return xprt;
 }