From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D5ECCC34047 for ; Wed, 19 Feb 2020 14:17:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B411720801 for ; Wed, 19 Feb 2020 14:17:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727680AbgBSORk (ORCPT ); Wed, 19 Feb 2020 09:17:40 -0500 Received: from mx2.suse.de ([195.135.220.15]:35298 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726736AbgBSORk (ORCPT ); Wed, 19 Feb 2020 09:17:40 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 26694AEFB; Wed, 19 Feb 2020 14:17:38 +0000 (UTC) Received: by ds.suse.cz (Postfix, from userid 10065) id 60CD5DA70E; Wed, 19 Feb 2020 15:17:21 +0100 (CET) From: David Sterba To: linux-btrfs@vger.kernel.org Cc: David Sterba Subject: [PATCH] btrfs: raid56: simplify tracking of Q stripe presence Date: Wed, 19 Feb 2020 15:17:20 +0100 Message-Id: <20200219141720.21549-1-dsterba@suse.com> X-Mailer: git-send-email 2.25.0 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org There are temporary variables tracking the index of P and Q stripes, but none of them is really used as such, merely for determining if the Q stripe is present. This leads to compiler warnings with -Wunused-but-set-variable and has been reported several times. fs/btrfs/raid56.c: In function ‘finish_rmw’: fs/btrfs/raid56.c:1199:6: warning: variable ‘p_stripe’ set but not used [-Wunused-but-set-variable] 1199 | int p_stripe = -1; | ^~~~~~~~ fs/btrfs/raid56.c: In function ‘finish_parity_scrub’: fs/btrfs/raid56.c:2356:6: warning: variable ‘p_stripe’ set but not used [-Wunused-but-set-variable] 2356 | int p_stripe = -1; | ^~~~~~~~ Replace the two variables with one that has a clear meaning and also get rid of the warnings. The logic that verifies that there are only 2 valid cases is unchanged. Signed-off-by: David Sterba --- fs/btrfs/raid56.c | 37 +++++++++++++++---------------------- 1 file changed, 15 insertions(+), 22 deletions(-) diff --git a/fs/btrfs/raid56.c b/fs/btrfs/raid56.c index a8e53c8e7b01..406b1efd3ba5 100644 --- a/fs/btrfs/raid56.c +++ b/fs/btrfs/raid56.c @@ -1196,22 +1196,19 @@ static noinline void finish_rmw(struct btrfs_raid_bio *rbio) int nr_data = rbio->nr_data; int stripe; int pagenr; - int p_stripe = -1; - int q_stripe = -1; + bool has_qstripe; struct bio_list bio_list; struct bio *bio; int ret; bio_list_init(&bio_list); - if (rbio->real_stripes - rbio->nr_data == 1) { - p_stripe = rbio->real_stripes - 1; - } else if (rbio->real_stripes - rbio->nr_data == 2) { - p_stripe = rbio->real_stripes - 2; - q_stripe = rbio->real_stripes - 1; - } else { + if (rbio->real_stripes - rbio->nr_data == 1) + has_qstripe = false; + else if (rbio->real_stripes - rbio->nr_data == 2) + has_qstripe = true; + else BUG(); - } /* at this point we either have a full stripe, * or we've read the full stripe from the drive. @@ -1255,7 +1252,7 @@ static noinline void finish_rmw(struct btrfs_raid_bio *rbio) SetPageUptodate(p); pointers[stripe++] = kmap(p); - if (q_stripe != -1) { + if (has_qstripe) { /* * raid6, add the qstripe and call the @@ -2353,8 +2350,7 @@ static noinline void finish_parity_scrub(struct btrfs_raid_bio *rbio, int nr_data = rbio->nr_data; int stripe; int pagenr; - int p_stripe = -1; - int q_stripe = -1; + bool has_qstripe; struct page *p_page = NULL; struct page *q_page = NULL; struct bio_list bio_list; @@ -2364,14 +2360,12 @@ static noinline void finish_parity_scrub(struct btrfs_raid_bio *rbio, bio_list_init(&bio_list); - if (rbio->real_stripes - rbio->nr_data == 1) { - p_stripe = rbio->real_stripes - 1; - } else if (rbio->real_stripes - rbio->nr_data == 2) { - p_stripe = rbio->real_stripes - 2; - q_stripe = rbio->real_stripes - 1; - } else { + if (rbio->real_stripes - rbio->nr_data == 1) + has_qstripe = false; + else if (rbio->real_stripes - rbio->nr_data == 2) + has_qstripe = true; + else BUG(); - } if (bbio->num_tgtdevs && bbio->tgtdev_map[rbio->scrubp]) { is_replace = 1; @@ -2393,7 +2387,7 @@ static noinline void finish_parity_scrub(struct btrfs_raid_bio *rbio, goto cleanup; SetPageUptodate(p_page); - if (q_stripe != -1) { + if (has_qstripe) { q_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM); if (!q_page) { __free_page(p_page); @@ -2416,8 +2410,7 @@ static noinline void finish_parity_scrub(struct btrfs_raid_bio *rbio, /* then add the parity stripe */ pointers[stripe++] = kmap(p_page); - if (q_stripe != -1) { - + if (has_qstripe) { /* * raid6, add the qstripe and call the * library function to fill in our p/q -- 2.25.0