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=-13.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,URIBL_BLOCKED autolearn=unavailable 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 AA7C2C433ED for ; Wed, 7 Apr 2021 03:39:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 730A46139E for ; Wed, 7 Apr 2021 03:39:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344435AbhDGDjB (ORCPT ); Tue, 6 Apr 2021 23:39:01 -0400 Received: from smtprelay0111.hostedemail.com ([216.40.44.111]:33612 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S234337AbhDGDi6 (ORCPT ); Tue, 6 Apr 2021 23:38:58 -0400 Received: from omf15.hostedemail.com (clb03-v110.bra.tucows.net [216.40.38.60]) by smtprelay07.hostedemail.com (Postfix) with ESMTP id 8704E181D337B; Wed, 7 Apr 2021 03:38:48 +0000 (UTC) Received: from [HIDDEN] (Authenticated sender: joe@perches.com) by omf15.hostedemail.com (Postfix) with ESMTPA id 6CCE6C4182; Wed, 7 Apr 2021 03:38:47 +0000 (UTC) Message-ID: Subject: Re: [PATCH][next] erofs: fix uninitialized variable i used in a while-loop From: Joe Perches To: Gao Xiang , Colin King Cc: Gao Xiang , Chao Yu , linux-erofs@lists.ozlabs.org, kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org Date: Tue, 06 Apr 2021 20:38:44 -0700 In-Reply-To: <20210406235401.GA210667@xiangao.remote.csb> References: <20210406162718.429852-1-colin.king@canonical.com> <20210406235401.GA210667@xiangao.remote.csb> Content-Type: text/plain; charset="ISO-8859-1" User-Agent: Evolution 3.38.1-1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Stat-Signature: ofx9em7xwsozzieswcpenrt3r3r95cat X-Rspamd-Server: rspamout05 X-Rspamd-Queue-Id: 6CCE6C4182 X-Session-Marker: 6A6F6540706572636865732E636F6D X-Session-ID: U2FsdGVkX19GKTF9FPXA2XYpIjjRK9qyadDR5X8MmkM= X-HE-Tag: 1617766727-223981 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2021-04-07 at 07:54 +0800, Gao Xiang wrote: > Hi Colin, > > On Tue, Apr 06, 2021 at 05:27:18PM +0100, Colin King wrote: > > From: Colin Ian King > > > > The while-loop iterates until src is non-null or i is 3, however, the > > loop counter i is not intinitialied to zero, causing incorrect iteration > > counts. Fix this by initializing it to zero. > > > > Addresses-Coverity: ("Uninitialized scalar variable") > > Fixes: 1aa5f2e2feed ("erofs: support decompress big pcluster for lz4 backend") > > Signed-off-by: Colin Ian King > > Thank you very much for catching this! It looks good to me, > Reviewed-by: Gao Xiang > > (btw, may I fold this into the original patchset? since such big pcluster >  patchset is just applied to for-next for further integration testing, and >  the commit id is not stable yet..) > > Thanks, > Gao Xiang I think this code is odd and would be more intelligible using a for loop like: --- fs/erofs/decompressor.c | 20 ++++++++------------ 1 file changed, 8 insertions(+), 12 deletions(-) diff --git a/fs/erofs/decompressor.c b/fs/erofs/decompressor.c index 27aa6a99b371..5a64f4649414 100644 --- a/fs/erofs/decompressor.c +++ b/fs/erofs/decompressor.c @@ -286,28 +286,24 @@ static int z_erofs_decompress_generic(struct z_erofs_decompress_req *rq, } ret = alg->prepare_destpages(rq, pagepool); - if (ret < 0) { + if (ret < 0) return ret; - } else if (ret) { + if (ret) { dst = page_address(*rq->out); dst_maptype = 1; goto dstmap_out; } - i = 0; - while (1) { + for (i = 0; i < 3; i++) { dst = vm_map_ram(rq->out, nrpages_out, -1); - + if (dst) { + dst_maptype = 2; + goto dstmap_out; + } /* retry two more times (totally 3 times) */ - if (dst || ++i >= 3) - break; vm_unmap_aliases(); } - - if (!dst) - return -ENOMEM; - - dst_maptype = 2; + return -ENOMEM; dstmap_out: ret = alg->decompress(rq, dst + rq->pageofs_out);