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=-8.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 27383C433E0 for ; Mon, 1 Jun 2020 14:29:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 021952077D for ; Mon, 1 Jun 2020 14:29:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="HXmbS5NV" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727994AbgFAO3W (ORCPT ); Mon, 1 Jun 2020 10:29:22 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:31064 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726067AbgFAO3V (ORCPT ); Mon, 1 Jun 2020 10:29:21 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1591021759; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=IDTwPNf3l6SEVDe9cErj295Q0DZm/J2XzLe6GU6mFfk=; b=HXmbS5NVhGVZ0u8mIW+tsg2IJ8om+NOTOXuFOLfmUGcWHUVkQdvhq5nleM5BUob0nyo2JA 4TZbWbvitKjzzzgSEJcxOwOkgZfYeQSGzVjRWdytP91ghGPIhupMof5sEaxoixH00/bclI ktpFfSVCxJ5m1E5wz5xuumP1yk3pjqc= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-53-P8WcvFC1N9OSsCWw6rx2GQ-1; Mon, 01 Jun 2020 10:29:15 -0400 X-MC-Unique: P8WcvFC1N9OSsCWw6rx2GQ-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 944B1835B43; Mon, 1 Jun 2020 14:29:14 +0000 (UTC) Received: from file01.intranet.prod.int.rdu2.redhat.com (file01.intranet.prod.int.rdu2.redhat.com [10.11.5.7]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 2BE26610AB; Mon, 1 Jun 2020 14:29:09 +0000 (UTC) Received: from file01.intranet.prod.int.rdu2.redhat.com (localhost [127.0.0.1]) by file01.intranet.prod.int.rdu2.redhat.com (8.14.4/8.14.4) with ESMTP id 051ET8id023708; Mon, 1 Jun 2020 10:29:08 -0400 Received: from localhost (mpatocka@localhost) by file01.intranet.prod.int.rdu2.redhat.com (8.14.4/8.14.4/Submit) with ESMTP id 051ET8q5023704; Mon, 1 Jun 2020 10:29:08 -0400 X-Authentication-Warning: file01.intranet.prod.int.rdu2.redhat.com: mpatocka owned process doing -bs Date: Mon, 1 Jun 2020 10:29:08 -0400 (EDT) From: Mikulas Patocka X-X-Sender: mpatocka@file01.intranet.prod.int.rdu2.redhat.com To: Huaisheng Ye cc: snitzer@redhat.com, agk@redhat.com, prarit@redhat.com, tyu1@lenovo.com, dm-devel@redhat.com, linux-kernel@vger.kernel.org, Huaisheng Ye Subject: Re: [PATCH] dm writecache: reinitialize lru in writeback instead of endio In-Reply-To: <20200530091250.58420-1-yehs2007@zoho.com> Message-ID: References: <20200530091250.58420-1-yehs2007@zoho.com> User-Agent: Alpine 2.02 (LRH 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 30 May 2020, Huaisheng Ye wrote: > From: Huaisheng Ye > > When wc_entry has been removed from wbl->list in writeback, it will > be not used again except waiting to be set free in writecache_free_entry. > > That is a little of annoying, it has to reinitialize lru of wc_entry > in endio before calling writecache_free_entry. > > Using list_del_init instead of list_del in writeback for simpler code. > > Signed-off-by: Huaisheng Ye This patch doesn't fix anything, so I think we don't need it. Actually, it's better to keep the list entry uninitialized, because it helps us catch bugs where this uninitialized list entry could be used improperly. Mikulas > --- > drivers/md/dm-writecache.c | 10 ++++------ > 1 file changed, 4 insertions(+), 6 deletions(-) > > diff --git a/drivers/md/dm-writecache.c b/drivers/md/dm-writecache.c > index 7bbc21b..66f3a3b 100644 > --- a/drivers/md/dm-writecache.c > +++ b/drivers/md/dm-writecache.c > @@ -1519,7 +1519,6 @@ static void __writecache_endio_pmem(struct dm_writecache *wc, struct list_head * > e = wb->wc_list[i]; > BUG_ON(!e->write_in_progress); > e->write_in_progress = false; > - INIT_LIST_HEAD(&e->lru); > if (!writecache_has_error(wc)) > writecache_free_entry(wc, e); > BUG_ON(!wc->writeback_size); > @@ -1555,7 +1554,6 @@ static void __writecache_endio_ssd(struct dm_writecache *wc, struct list_head *l > do { > BUG_ON(!e->write_in_progress); > e->write_in_progress = false; > - INIT_LIST_HEAD(&e->lru); > if (!writecache_has_error(wc)) > writecache_free_entry(wc, e); > > @@ -1654,7 +1652,7 @@ static void __writecache_writeback_pmem(struct dm_writecache *wc, struct writeba > while (wbl->size) { > wbl->size--; > e = container_of(wbl->list.prev, struct wc_entry, lru); > - list_del(&e->lru); > + list_del_init(&e->lru); > > max_pages = e->wc_list_contiguous; > > @@ -1685,7 +1683,7 @@ static void __writecache_writeback_pmem(struct dm_writecache *wc, struct writeba > if (!wc_add_block(wb, f, GFP_NOWAIT | __GFP_NOWARN)) > break; > wbl->size--; > - list_del(&f->lru); > + list_del_init(&f->lru); > wb->wc_list[wb->wc_list_n++] = f; > e = f; > } > @@ -1712,7 +1710,7 @@ static void __writecache_writeback_ssd(struct dm_writecache *wc, struct writebac > > wbl->size--; > e = container_of(wbl->list.prev, struct wc_entry, lru); > - list_del(&e->lru); > + list_del_init(&e->lru); > > n_sectors = e->wc_list_contiguous << (wc->block_size_bits - SECTOR_SHIFT); > > @@ -1732,7 +1730,7 @@ static void __writecache_writeback_ssd(struct dm_writecache *wc, struct writebac > wbl->size--; > f = container_of(wbl->list.prev, struct wc_entry, lru); > BUG_ON(f != e + 1); > - list_del(&f->lru); > + list_del_init(&f->lru); > e = f; > } > > -- > 1.8.3.1 >