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=-9.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY 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 6B704C433E7 for ; Thu, 15 Oct 2020 04:02:12 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id ED61822241 for ; Thu, 15 Oct 2020 04:02:11 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org ED61822241 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 135216B0062; Thu, 15 Oct 2020 00:02:11 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 0E5A16B0068; Thu, 15 Oct 2020 00:02:11 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id EC7976B006E; Thu, 15 Oct 2020 00:02:10 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0148.hostedemail.com [216.40.44.148]) by kanga.kvack.org (Postfix) with ESMTP id BE8D96B0062 for ; Thu, 15 Oct 2020 00:02:10 -0400 (EDT) Received: from smtpin25.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 505548249980 for ; Thu, 15 Oct 2020 04:02:10 +0000 (UTC) X-FDA: 77372812020.25.war23_0d17e5f27211 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin25.hostedemail.com (Postfix) with ESMTP id 2C5AB1804E3A0 for ; Thu, 15 Oct 2020 04:02:10 +0000 (UTC) X-HE-Tag: war23_0d17e5f27211 X-Filterd-Recvd-Size: 2778 Received: from out30-45.freemail.mail.aliyun.com (out30-45.freemail.mail.aliyun.com [115.124.30.45]) by imf46.hostedemail.com (Postfix) with ESMTP for ; Thu, 15 Oct 2020 04:02:08 +0000 (UTC) X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R121e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04420;MF=richard.weiyang@linux.alibaba.com;NM=1;PH=DS;RN=8;SR=0;TI=SMTPD_---0UC3mqed_1602734524; Received: from localhost(mailfrom:richard.weiyang@linux.alibaba.com fp:SMTPD_---0UC3mqed_1602734524) by smtp.aliyun-inc.com(127.0.0.1); Thu, 15 Oct 2020 12:02:05 +0800 Date: Thu, 15 Oct 2020 12:02:04 +0800 From: Wei Yang To: David Hildenbrand Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, virtualization@lists.linux-foundation.org, Andrew Morton , "Michael S . Tsirkin" , Jason Wang , Pankaj Gupta Subject: Re: [PATCH v1 02/29] virtio-mem: simplify calculation in virtio_mem_mb_state_prepare_next_mb() Message-ID: <20201015040204.GB86495@L-31X9LVDL-1304.local> Reply-To: Wei Yang References: <20201012125323.17509-1-david@redhat.com> <20201012125323.17509-3-david@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201012125323.17509-3-david@redhat.com> X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Mon, Oct 12, 2020 at 02:52:56PM +0200, David Hildenbrand wrote: >We actually need one byte less (next_mb_id is exclusive, first_mb_id is >inclusive). Simplify. > >Cc: "Michael S. Tsirkin" >Cc: Jason Wang >Cc: Pankaj Gupta >Signed-off-by: David Hildenbrand >--- > drivers/virtio/virtio_mem.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > >diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c >index a1f5bf7a571a..670b3faf412d 100644 >--- a/drivers/virtio/virtio_mem.c >+++ b/drivers/virtio/virtio_mem.c >@@ -257,8 +257,8 @@ static enum virtio_mem_mb_state virtio_mem_mb_get_state(struct virtio_mem *vm, > */ > static int virtio_mem_mb_state_prepare_next_mb(struct virtio_mem *vm) > { >- unsigned long old_bytes = vm->next_mb_id - vm->first_mb_id + 1; >- unsigned long new_bytes = vm->next_mb_id - vm->first_mb_id + 2; >+ unsigned long old_bytes = vm->next_mb_id - vm->first_mb_id; >+ unsigned long new_bytes = old_bytes + 1; This is correct. So this looks more like a fix? > int old_pages = PFN_UP(old_bytes); > int new_pages = PFN_UP(new_bytes); > uint8_t *new_mb_state; >-- >2.26.2 -- Wei Yang Help you, Help me