From mboxrd@z Thu Jan 1 00:00:00 1970 From: Roland Dreier Subject: cxgb3: Fix sparse warning and micro-optimize is_pure_response() Date: Fri, 28 Nov 2008 21:47:03 -0800 Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: netdev@vger.kernel.org To: Divy Le Ray , Jeff Garzik Return-path: Received: from sj-iport-2.cisco.com ([171.71.176.71]:59315 "EHLO sj-iport-2.cisco.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750701AbYK2FrG (ORCPT ); Sat, 29 Nov 2008 00:47:06 -0500 Sender: netdev-owner@vger.kernel.org List-ID: The function is_pure_response() does "ntohl(var) & const" and then essentially just tests whether the result is 0 or not; this can be done more efficiently by computing "var & htonl(const)" instead and doing the byte swap at compile time instead of run time. This change slightly shrinks the compiled code; eg on x86-64 we save a couple of bswapl instructions: add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-8 (-8) function old new delta t3_sge_intr_msix_napi 544 536 -8 and this also has the pleasant side effect of fixing a sparse warning: drivers/net/cxgb3/sge.c:2313:15: warning: restricted degrades to integer Signed-off-by: Roland Dreier --- drivers/net/cxgb3/sge.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/drivers/net/cxgb3/sge.c b/drivers/net/cxgb3/sge.c index c6480be..4181373 100644 --- a/drivers/net/cxgb3/sge.c +++ b/drivers/net/cxgb3/sge.c @@ -2308,7 +2308,7 @@ next_fl: static inline int is_pure_response(const struct rsp_desc *r) { - u32 n = ntohl(r->flags) & (F_RSPD_ASYNC_NOTIF | F_RSPD_IMM_DATA_VALID); + __be32 n = r->flags & htonl(F_RSPD_ASYNC_NOTIF | F_RSPD_IMM_DATA_VALID); return (n | r->len_cq) == 0; }