ceph: avoid block operation when !TASK_RUNNING (ceph_mdsc_close_sessions)
use an atomic variable to track number of sessions, this can avoid block
operation inside wait loops.
Signed-off-by: Yan, Zheng <zyan@redhat.com>
diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index fdf5cc8..c90ca99 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -480,6 +480,7 @@
mdsc->max_sessions = newmax;
}
mdsc->sessions[mds] = s;
+ atomic_inc(&mdsc->num_sessions);
atomic_inc(&s->s_ref); /* one ref to sessions[], one to caller */
ceph_con_open(&s->s_con, CEPH_ENTITY_TYPE_MDS, mds,
@@ -503,6 +504,7 @@
mdsc->sessions[s->s_mds] = NULL;
ceph_con_close(&s->s_con);
ceph_put_mds_session(s);
+ atomic_dec(&mdsc->num_sessions);
}
/*
@@ -3328,6 +3330,7 @@
init_waitqueue_head(&mdsc->session_close_wq);
INIT_LIST_HEAD(&mdsc->waiting_for_map);
mdsc->sessions = NULL;
+ atomic_set(&mdsc->num_sessions, 0);
mdsc->max_sessions = 0;
mdsc->stopping = 0;
init_rwsem(&mdsc->snap_rwsem);
@@ -3479,17 +3482,9 @@
*/
static bool done_closing_sessions(struct ceph_mds_client *mdsc)
{
- int i, n = 0;
-
if (mdsc->fsc->mount_state == CEPH_MOUNT_SHUTDOWN)
return true;
-
- mutex_lock(&mdsc->mutex);
- for (i = 0; i < mdsc->max_sessions; i++)
- if (mdsc->sessions[i])
- n++;
- mutex_unlock(&mdsc->mutex);
- return n == 0;
+ return atomic_read(&mdsc->num_sessions) == 0;
}
/*