From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752701AbbFHJAF (ORCPT ); Mon, 8 Jun 2015 05:00:05 -0400 Received: from mail-pd0-f182.google.com ([209.85.192.182]:35472 "EHLO mail-pd0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752272AbbFHI7o (ORCPT ); Mon, 8 Jun 2015 04:59:44 -0400 From: Tejun Heo To: axboe@kernel.dk Cc: linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, vgoyal@redhat.com, avanzini.arianna@gmail.com, Tejun Heo Subject: [PATCH 1/8] cfq-iosched: simplify control flow in cfq_get_queue() Date: Mon, 8 Jun 2015 17:59:26 +0900 Message-Id: <1433753973-23684-2-git-send-email-tj@kernel.org> X-Mailer: git-send-email 2.4.2 In-Reply-To: <1433753973-23684-1-git-send-email-tj@kernel.org> References: <1433753973-23684-1-git-send-email-tj@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org cfq_get_queue()'s control flow looks like the following. async_cfqq = NULL; cfqq = NULL; if (!is_sync) { ... async_cfqq = ...; cfqq = *async_cfqq; } if (!cfqq) cfqq = ...; if (!is_sync && !(*async_cfqq)) ...; The only thing the local variable init, the second if, and the async_cfqq test in the third if achieves is to skip cfqq creation and installation if *async_cfqq was already non-NULL. This is needlessly complicated with different tests examining the same condition. Simplify it to the following. if (!is_sync) { ... async_cfqq = ...; cfqq = *async_cfqq; if (cfqq) goto out; } cfqq = ...; if (!is_sync) ...; out: Signed-off-by: Tejun Heo Cc: Vivek Goyal Cc: Arianna Avanzini --- block/cfq-iosched.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index bc8f429..2814bb7 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -3663,8 +3663,8 @@ cfq_get_queue(struct cfq_data *cfqd, bool is_sync, struct cfq_io_cq *cic, { int ioprio_class = IOPRIO_PRIO_CLASS(cic->ioprio); int ioprio = IOPRIO_PRIO_DATA(cic->ioprio); - struct cfq_queue **async_cfqq = NULL; - struct cfq_queue *cfqq = NULL; + struct cfq_queue **async_cfqq; + struct cfq_queue *cfqq; if (!is_sync) { if (!ioprio_valid(cic->ioprio)) { @@ -3674,19 +3674,20 @@ cfq_get_queue(struct cfq_data *cfqd, bool is_sync, struct cfq_io_cq *cic, } async_cfqq = cfq_async_queue_prio(cfqd, ioprio_class, ioprio); cfqq = *async_cfqq; + if (cfqq) + goto out; } - if (!cfqq) - cfqq = cfq_find_alloc_queue(cfqd, is_sync, cic, bio, gfp_mask); + cfqq = cfq_find_alloc_queue(cfqd, is_sync, cic, bio, gfp_mask); /* * pin the queue now that it's allocated, scheduler exit will prune it */ - if (!is_sync && !(*async_cfqq)) { + if (!is_sync) { cfqq->ref++; *async_cfqq = cfqq; } - +out: cfqq->ref++; return cfqq; } -- 2.4.2