All of lore.kernel.org
 help / color / mirror / Atom feed
From: Hannes Reinecke <hare@suse.de>
To: Ilya Dryomov <idryomov@gmail.com>
Cc: Sage Weil <sage@redhat.com>, Daniel Disseldorp <ddiss@suse.com>,
	Jens Axboe <axboe@kernel.dk>,
	ceph-devel@vger.kernel.org, linux-block@vger.kernel.org,
	Hannes Reinecke <hare@suse.de>
Subject: [PATCH 04/15] rbd: reorder switch statement in rbd_advance_read()
Date: Fri, 31 Jan 2020 11:37:28 +0100	[thread overview]
Message-ID: <20200131103739.136098-5-hare@suse.de> (raw)
In-Reply-To: <20200131103739.136098-1-hare@suse.de>

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 <hare@suse.de>
---
 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();
-- 
2.16.4


  parent reply	other threads:[~2020-01-31 10:38 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-31 10:37 [PATCH 00/15] rbd: switch to blk-mq Hannes Reinecke
2020-01-31 10:37 ` [PATCH 01/15] rbd: lock object request list Hannes Reinecke
2020-02-03 16:38   ` Ilya Dryomov
2020-01-31 10:37 ` [PATCH 02/15] rbd: use READ_ONCE() when checking the mapping size Hannes Reinecke
2020-02-03 16:50   ` Ilya Dryomov
2020-02-04  7:05     ` Hannes Reinecke
2020-01-31 10:37 ` [PATCH 03/15] rbd: reorder rbd_img_advance() Hannes Reinecke
2020-01-31 10:37 ` Hannes Reinecke [this message]
2020-01-31 10:37 ` [PATCH 05/15] rbd: reorder switch statement in rbd_advance_write() Hannes Reinecke
2020-01-31 10:37 ` [PATCH 06/15] rbd: add 'done' state for rbd_obj_advance_copyup() Hannes Reinecke
2020-01-31 10:37 ` [PATCH 07/15] rbd: use callback for image request completion Hannes Reinecke
2020-02-03 17:13   ` Ilya Dryomov
2020-01-31 10:37 ` [PATCH 08/15] rbd: add debugging statements for the state machine Hannes Reinecke
2020-01-31 10:37 ` [PATCH 09/15] rbd: count pending object requests in-line Hannes Reinecke
2020-02-03 17:47   ` Ilya Dryomov
2020-02-04  6:59     ` Hannes Reinecke
2020-01-31 10:37 ` [PATCH 10/15] rbd: kill 'work_result' Hannes Reinecke
2020-01-31 10:37 ` [PATCH 11/15] rbd: drop state_mutex in __rbd_img_handle_request() Hannes Reinecke
2020-02-03 18:01   ` Ilya Dryomov
2020-01-31 10:37 ` [PATCH 12/15] rbd: kill img_request kref Hannes Reinecke
2020-01-31 10:37 ` [PATCH 13/15] rbd: schedule image_request after preparation Hannes Reinecke
2020-02-03 18:40   ` Ilya Dryomov
2020-01-31 10:37 ` [PATCH 14/15] rbd: embed image request as blk_mq request payload Hannes Reinecke
2020-01-31 10:37 ` [PATCH 15/15] rbd: switch to blk-mq Hannes Reinecke
2020-02-03  8:36   ` Christoph Hellwig

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200131103739.136098-5-hare@suse.de \
    --to=hare@suse.de \
    --cc=axboe@kernel.dk \
    --cc=ceph-devel@vger.kernel.org \
    --cc=ddiss@suse.com \
    --cc=idryomov@gmail.com \
    --cc=linux-block@vger.kernel.org \
    --cc=sage@redhat.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.