This patch defines a single function, queue_con_delay() to call
queue_delayed_work() for a connection. It basically generalizes
what was previously queue_con() by adding the delay argument.
queue_con() is now a simple helper that passes 0 for its delay.
queue_con_delay() returns 0 if it queued work or an errno if it
did not for some reason.
If con_work() finds the BACKOFF flag set for a connection, it now
calls queue_con_delay() to handle arranging to start again after a
delay.
Note about connection reference counts: con_work() only ever gets
called as a work item function. At the time that work is scheduled,
a reference to the connection is acquired, and the corresponding
con_work() call is then responsible for dropping that reference
before it returns.
Previously, the backoff handling inside con_work() silently handed
off its reference to delayed work it scheduled. Now that
queue_con_delay() is used, a new reference is acquired for the
newly-scheduled work, and the original reference is dropped by the
con->ops->put() call at the end of the function.
Signed-off-by: Alex Elder <elder@xxxxxxxxxxx>
---
net/ceph/messenger.c | 38 +++++++++++++++++++++++---------------
1 file changed, 23 insertions(+), 15 deletions(-)
diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index 9170c20..77cc8b1 100644
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -2244,22 +2244,33 @@ bad_tag:
/*
- * Atomically queue work on a connection. Bump @con reference to
- * avoid races with connection teardown.
+ * Atomically queue work on a connection after the specified delay.
+ * Bump @con reference to avoid races with connection teardown.
+ * Returns 0 if work was queued, or an error code otherwise.
*/
-static void queue_con(struct ceph_connection *con)
+static int queue_con_delay(struct ceph_connection *con, unsigned long
delay)
{
if (!con->ops->get(con)) {
- dout("queue_con %p ref count 0\n", con);
- return;
+ dout("%s %p ref count 0\n", __func__, con);
+
+ return -ENOENT;
}
- if (!queue_delayed_work(ceph_msgr_wq, &con->work, 0)) {
- dout("queue_con %p - already queued\n", con);
+ if (!queue_delayed_work(ceph_msgr_wq, &con->work, delay)) {
+ dout("%s %p - already queued\n", __func__, con);
con->ops->put(con);
- } else {
- dout("queue_con %p\n", con);
+
+ return -EBUSY;
}
+
+ dout("%s %p %lu\n", __func__, con, delay);
+
+ return 0;
+}
+
+static void queue_con(struct ceph_connection *con)
+{
+ (void) queue_con_delay(con, 0);
}
/*
@@ -2294,14 +2305,11 @@ restart:
if (test_and_clear_bit(CON_FLAG_BACKOFF, &con->flags)) {
dout("con_work %p backing off\n", con);
- if (queue_delayed_work(ceph_msgr_wq, &con->work,
- round_jiffies_relative(con->delay))) {
- dout("con_work %p backoff %lu\n", con, con->delay);
- mutex_unlock(&con->mutex);
- return;
- } else {
+ ret = queue_con_delay(con, round_jiffies_relative(con->delay));
+ if (ret) {
dout("con_work %p FAILED to back off %lu\n", con,
con->delay);
+ BUG_ON(ret == -ENOENT);
set_bit(CON_FLAG_BACKOFF, &con->flags);
}
goto done;
--
1.7.9.5
--
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