From patchwork Fri Jan 31 10:37:28 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hannes Reinecke X-Patchwork-Id: 11359595 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 3AEFB112B for ; Fri, 31 Jan 2020 10:38:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 236FB206F0 for ; Fri, 31 Jan 2020 10:38:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728365AbgAaKiE (ORCPT ); Fri, 31 Jan 2020 05:38:04 -0500 Received: from mx2.suse.de ([195.135.220.15]:55736 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728336AbgAaKiD (ORCPT ); Fri, 31 Jan 2020 05:38:03 -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 89C9BAF43; Fri, 31 Jan 2020 10:38:01 +0000 (UTC) From: Hannes Reinecke To: Ilya Dryomov Cc: Sage Weil , Daniel Disseldorp , Jens Axboe , ceph-devel@vger.kernel.org, linux-block@vger.kernel.org, Hannes Reinecke Subject: [PATCH 04/15] rbd: reorder switch statement in rbd_advance_read() Date: Fri, 31 Jan 2020 11:37:28 +0100 Message-Id: <20200131103739.136098-5-hare@suse.de> X-Mailer: git-send-email 2.16.4 In-Reply-To: <20200131103739.136098-1-hare@suse.de> References: <20200131103739.136098-1-hare@suse.de> Sender: ceph-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: ceph-devel@vger.kernel.org Reorder switch statement to avoid the use of a label/goto statement and add a 'done' state to indicate that the state machine has completed. Signed-off-by: Hannes Reinecke --- drivers/block/rbd.c | 31 +++++++++++++++++++------------ 1 file changed, 19 insertions(+), 12 deletions(-) diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c index c80942e08164..4d7857667e9c 100644 --- a/drivers/block/rbd.c +++ b/drivers/block/rbd.c @@ -235,7 +235,8 @@ enum obj_operation_type { #define RBD_OBJ_FLAG_NOOP_FOR_NONEXISTENT (1U << 4) enum rbd_obj_read_state { - RBD_OBJ_READ_START = 1, + RBD_OBJ_READ_DONE, + RBD_OBJ_READ_START, RBD_OBJ_READ_OBJECT, RBD_OBJ_READ_PARENT, }; @@ -2924,36 +2925,38 @@ static bool rbd_obj_advance_read(struct rbd_obj_request *obj_req, int *result) struct rbd_device *rbd_dev = obj_req->img_request->rbd_dev; int ret; -again: + dout("%s: obj %p state %d\n", __func__, obj_req, obj_req->read_state); switch (obj_req->read_state) { case RBD_OBJ_READ_START: rbd_assert(!*result); - if (!rbd_obj_may_exist(obj_req)) { - *result = -ENOENT; + if (rbd_obj_may_exist(obj_req)) { + ret = rbd_obj_read_object(obj_req); + if (ret) { + *result = ret; + obj_req->read_state = RBD_OBJ_READ_DONE; + return true; + } obj_req->read_state = RBD_OBJ_READ_OBJECT; - goto again; - } - - ret = rbd_obj_read_object(obj_req); - if (ret) { - *result = ret; - return true; + return false; } + *result = -ENOENT; obj_req->read_state = RBD_OBJ_READ_OBJECT; - return false; + /* fall through */ case RBD_OBJ_READ_OBJECT: if (*result == -ENOENT && rbd_dev->parent_overlap) { /* reverse map this object extent onto the parent */ ret = rbd_obj_calc_img_extents(obj_req, false); if (ret) { *result = ret; + obj_req->read_state = RBD_OBJ_READ_DONE; return true; } if (obj_req->num_img_extents) { ret = rbd_obj_read_from_parent(obj_req); if (ret) { *result = ret; + obj_req->read_state = RBD_OBJ_READ_DONE; return true; } obj_req->read_state = RBD_OBJ_READ_PARENT; @@ -2977,6 +2980,7 @@ static bool rbd_obj_advance_read(struct rbd_obj_request *obj_req, int *result) rbd_assert(*result == obj_req->ex.oe_len); *result = 0; } + obj_req->read_state = RBD_OBJ_READ_DONE; return true; case RBD_OBJ_READ_PARENT: /* @@ -2990,6 +2994,9 @@ static bool rbd_obj_advance_read(struct rbd_obj_request *obj_req, int *result) rbd_obj_zero_range(obj_req, obj_overlap, obj_req->ex.oe_len - obj_overlap); } + obj_req->read_state = RBD_OBJ_READ_DONE; + /* fall through */ + case RBD_OBJ_READ_DONE: return true; default: BUG();