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
next prev 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
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