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bh=AhgYzUpwMNgQ02/bpbyCiWPXN35G78wveHycbIr0fak=; b=be792ephMvh4hbyPZx4LEiNOwpOF+dwHrg5+AopZxKTSPh8Ev9+QTZ8kmgM60bsJBRcM3Q nE5DGw6F86Jwl8EbIrydwSSB+6pf9q5zPuJTGw/cGGlpWKaRC1S3FAB3/tHFfgw20uD8dq ugnGGxa0O8NJyaDXDJM9jpHtC0z5J3w= 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-572-KeBzTyX2O--uG-vhHGatzw-1; Mon, 18 Jan 2021 10:40:27 -0500 X-MC-Unique: KeBzTyX2O--uG-vhHGatzw-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id E4004107ACE4; Mon, 18 Jan 2021 15:40:25 +0000 (UTC) Received: from merkur.fritz.box (ovpn-115-75.ams2.redhat.com [10.36.115.75]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 66F631820E; Mon, 18 Jan 2021 15:40:23 +0000 (UTC) Date: Mon, 18 Jan 2021 16:40:22 +0100 From: Kevin Wolf To: Vladimir Sementsov-Ogievskiy Subject: Re: [PATCH v2 09/36] block: return value from bdrv_replace_node() Message-ID: <20210118154022.GI11555@merkur.fritz.box> References: <20201127144522.29991-1-vsementsov@virtuozzo.com> <20201127144522.29991-10-vsementsov@virtuozzo.com> MIME-Version: 1.0 In-Reply-To: <20201127144522.29991-10-vsementsov@virtuozzo.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=kwolf@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Received-SPF: pass client-ip=63.128.21.124; envelope-from=kwolf@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -29 X-Spam_score: -3.0 X-Spam_bar: --- X-Spam_report: (-3.0 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.175, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: qemu-block@nongnu.org, armbru@redhat.com, qemu-devel@nongnu.org, mreitz@redhat.com, den@openvz.org, jsnow@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Am 27.11.2020 um 15:44 hat Vladimir Sementsov-Ogievskiy geschrieben: > Functions with errp argument are not recommened to be void-functions. > Improve bdrv_replace_node(). > > Signed-off-by: Vladimir Sementsov-Ogievskiy > --- > include/block/block.h | 4 ++-- > block.c | 14 ++++++++------ > 2 files changed, 10 insertions(+), 8 deletions(-) > > diff --git a/include/block/block.h b/include/block/block.h > index 5d59984ad4..8f6100dad7 100644 > --- a/include/block/block.h > +++ b/include/block/block.h > @@ -346,8 +346,8 @@ int bdrv_create_file(const char *filename, QemuOpts *opts, Error **errp); > BlockDriverState *bdrv_new(void); > int bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top, > Error **errp); > -void bdrv_replace_node(BlockDriverState *from, BlockDriverState *to, > - Error **errp); > +int bdrv_replace_node(BlockDriverState *from, BlockDriverState *to, > + Error **errp); > > int bdrv_parse_aio(const char *mode, int *flags); > int bdrv_parse_cache_mode(const char *mode, int *flags, bool *writethrough); > diff --git a/block.c b/block.c > index 3765c7caed..29082c6d47 100644 > --- a/block.c > +++ b/block.c > @@ -4537,14 +4537,14 @@ static bool should_update_child(BdrvChild *c, BlockDriverState *to) > * With auto_skip=false the error is returned if from has a parent which should > * not be updated. > */ > -static void bdrv_replace_node_common(BlockDriverState *from, > - BlockDriverState *to, > - bool auto_skip, Error **errp) > +static int bdrv_replace_node_common(BlockDriverState *from, > + BlockDriverState *to, > + bool auto_skip, Error **errp) > { > + int ret = -EPERM; > BdrvChild *c, *next; > GSList *list = NULL, *p; > uint64_t perm = 0, shared = BLK_PERM_ALL; > - int ret; I think I'd prefer setting ret in each error path. This makes it more obvious that ret has the right value and hasn't been modified between the initialisation and the error. > > /* Make sure that @from doesn't go away until we have successfully attached > * all of its parents to @to. */ > @@ -4600,10 +4600,12 @@ out: Let's add an explicit ret = 0 right before the out: label. > g_slist_free(list); > bdrv_drained_end(from); > bdrv_unref(from); > + > + return ret; > } With these changes: Reviewed-by: Kevin Wolf