From 802c6d967fbdcd2cbc91b917425661bb8bbfaade Mon Sep 17 00:00:00 2001 From: Alex Elder Date: Mon, 8 Oct 2012 20:37:30 -0700 Subject: [PATCH] rbd: define common queue_con_delay() 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 Reviewed-by: Sage Weil --- 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 973c16c20c42..66f6f56bcb23 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; -- 2.20.1