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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 03/15] rbd: reorder rbd_img_advance()
Date: Fri, 31 Jan 2020 11:37:27 +0100	[thread overview]
Message-ID: <20200131103739.136098-4-hare@suse.de> (raw)
In-Reply-To: <20200131103739.136098-1-hare@suse.de>

Reorder switch statement to avoid the use of a label/goto and add
an RBD_IMG_DONE state to signal that the state machine has completed.

Signed-off-by: Hannes Reinecke <hare@suse.de>
---
 drivers/block/rbd.c | 30 +++++++++++++++++-------------
 1 file changed, 17 insertions(+), 13 deletions(-)

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 792180548e89..c80942e08164 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -321,9 +321,9 @@ enum img_req_flags {
 };
 
 enum rbd_img_state {
-	RBD_IMG_START = 1,
+	RBD_IMG_DONE,
+	RBD_IMG_START,
 	RBD_IMG_EXCLUSIVE_LOCK,
-	__RBD_IMG_OBJECT_REQUESTS,
 	RBD_IMG_OBJECT_REQUESTS,
 };
 
@@ -3591,40 +3591,44 @@ static bool rbd_img_advance(struct rbd_img_request *img_req, int *result)
 	struct rbd_device *rbd_dev = img_req->rbd_dev;
 	int ret;
 
-again:
+	dout("%s: img %p state %d\n", __func__, img_req, img_req->state);
 	switch (img_req->state) {
 	case RBD_IMG_START:
 		rbd_assert(!*result);
 
+		img_req->state = RBD_IMG_EXCLUSIVE_LOCK;
 		ret = rbd_img_exclusive_lock(img_req);
 		if (ret < 0) {
 			*result = ret;
+			img_req->state = RBD_IMG_DONE;
 			return true;
 		}
-		img_req->state = RBD_IMG_EXCLUSIVE_LOCK;
-		if (ret > 0)
-			goto again;
-		return false;
+		if (ret == 0)
+			return false;
+		/* fall through */
 	case RBD_IMG_EXCLUSIVE_LOCK:
-		if (*result)
+		if (*result) {
+			img_req->state = RBD_IMG_DONE;
 			return true;
+		}
 
 		rbd_assert(!need_exclusive_lock(img_req) ||
 			   __rbd_is_lock_owner(rbd_dev));
 
+		img_req->state = RBD_IMG_OBJECT_REQUESTS;
 		rbd_img_object_requests(img_req);
 		if (!img_req->pending.num_pending) {
 			*result = img_req->pending.result;
-			img_req->state = RBD_IMG_OBJECT_REQUESTS;
-			goto again;
+			img_req->state = RBD_IMG_DONE;
+			return true;
 		}
-		img_req->state = __RBD_IMG_OBJECT_REQUESTS;
 		return false;
-	case __RBD_IMG_OBJECT_REQUESTS:
+	case RBD_IMG_OBJECT_REQUESTS:
 		if (!pending_result_dec(&img_req->pending, result))
 			return false;
+		img_req->state = RBD_IMG_DONE;
 		/* fall through */
-	case RBD_IMG_OBJECT_REQUESTS:
+	case RBD_IMG_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 ` Hannes Reinecke [this message]
2020-01-31 10:37 ` [PATCH 04/15] rbd: reorder switch statement in rbd_advance_read() Hannes Reinecke
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

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