drbd: Basic refcounting for drbd_tconn
References hold by:
* Each (running) drbd thread has a reference on tconn
* Each mdev has a referenc on tconn
* Beeing in the all_tconn list counts for one reference
* Each after_conn_state_chg_work has a reference to tconn
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index 0fb3fc3..3abf982 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -828,6 +828,7 @@
struct drbd_tconn { /* is a resource from the config file */
char *name; /* Resource name */
struct list_head all_tconn; /* linked on global drbd_tconns */
+ struct kref kref;
struct idr volumes; /* <tconn, vnr> to mdev mapping */
enum drbd_conns cstate; /* Only C_STANDALONE to C_WF_REPORT_PARAMS */
unsigned susp:1; /* IO suspended by user */
@@ -1378,8 +1379,8 @@
enum drbd_ret_code conn_new_minor(struct drbd_tconn *tconn, unsigned int minor, int vnr);
extern void drbd_delete_device(struct drbd_conf *mdev);
-struct drbd_tconn *drbd_new_tconn(const char *name);
-extern void drbd_free_tconn(struct drbd_tconn *tconn);
+struct drbd_tconn *conn_create(const char *name);
+extern void conn_destroy(struct kref *kref);
struct drbd_tconn *conn_by_name(const char *name);
extern void conn_free_crypto(struct drbd_tconn *tconn);
diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index b9c103f..11427f5 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -509,6 +509,8 @@
conn_info(tconn, "Terminating %s\n", current->comm);
/* Release mod reference taken when thread was started */
+
+ kref_put(&tconn->kref, &conn_destroy);
module_put(THIS_MODULE);
return retval;
}
@@ -546,6 +548,8 @@
return false;
}
+ kref_get(&thi->tconn->kref);
+
init_completion(&thi->stop);
thi->reset_cpu_mask = 1;
thi->t_state = RUNNING;
@@ -558,6 +562,7 @@
if (IS_ERR(nt)) {
conn_err(tconn, "Couldn't start thread\n");
+ kref_put(&tconn->kref, &conn_destroy);
module_put(THIS_MODULE);
return false;
}
@@ -2237,6 +2242,8 @@
/* caution. no locking. */
void drbd_delete_device(struct drbd_conf *mdev)
{
+ struct drbd_tconn *tconn = mdev->tconn;
+
idr_remove(&mdev->tconn->volumes, mdev->vnr);
idr_remove(&minors, mdev_to_minor(mdev));
synchronize_rcu();
@@ -2272,6 +2279,8 @@
put_disk(mdev->vdisk);
blk_cleanup_queue(mdev->rq_queue);
kfree(mdev);
+
+ kref_put(&tconn->kref, &conn_destroy);
}
static void drbd_cleanup(void)
@@ -2409,7 +2418,7 @@
tconn->int_dig_vv = NULL;
}
-struct drbd_tconn *drbd_new_tconn(const char *name)
+struct drbd_tconn *conn_create(const char *name)
{
struct drbd_tconn *tconn;
@@ -2455,6 +2464,7 @@
};
down_write(&drbd_cfg_rwsem);
+ kref_init(&tconn->kref);
list_add_tail(&tconn->all_tconn, &drbd_tconns);
up_write(&drbd_cfg_rwsem);
@@ -2471,9 +2481,10 @@
return NULL;
}
-void drbd_free_tconn(struct drbd_tconn *tconn)
+void conn_destroy(struct kref *kref)
{
- list_del(&tconn->all_tconn);
+ struct drbd_tconn *tconn = container_of(kref, struct drbd_tconn, kref);
+
idr_destroy(&tconn->volumes);
free_cpumask_var(tconn->cpu_mask);
@@ -2503,7 +2514,9 @@
if (!mdev)
return ERR_NOMEM;
+ kref_get(&tconn->kref);
mdev->tconn = tconn;
+
mdev->minor = minor;
mdev->vnr = vnr;
@@ -2605,6 +2618,7 @@
blk_cleanup_queue(q);
out_no_q:
kfree(mdev);
+ kref_put(&tconn->kref, &conn_destroy);
return err;
}
diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index fff11ae..23c34ba 100644
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -479,6 +479,7 @@
conn_try_outdate_peer(tconn);
+ kref_put(&tconn->kref, &conn_destroy);
return 0;
}
@@ -486,9 +487,12 @@
{
struct task_struct *opa;
+ kref_get(&tconn->kref);
opa = kthread_run(_try_outdate_peer_async, tconn, "drbd_async_h");
- if (IS_ERR(opa))
+ if (IS_ERR(opa)) {
conn_err(tconn, "out of mem, failed to invoke fence-peer helper\n");
+ kref_put(&tconn->kref, &conn_destroy);
+ }
}
enum drbd_state_rv
@@ -2627,7 +2631,7 @@
* on each iteration.
*/
- /* synchronize with drbd_new_tconn/drbd_free_tconn */
+ /* synchronize with conn_create()/conn_destroy() */
down_read(&drbd_cfg_rwsem);
/* revalidate iterator position */
list_for_each_entry(tmp, &drbd_tconns, all_tconn) {
@@ -2932,7 +2936,7 @@
goto out;
}
- if (!drbd_new_tconn(adm_ctx.conn_name))
+ if (!conn_create(adm_ctx.conn_name))
retcode = ERR_NOMEM;
out:
drbd_adm_finish(info, retcode);
@@ -3005,10 +3009,6 @@
down_write(&drbd_cfg_rwsem);
retcode = adm_delete_minor(adm_ctx.mdev);
up_write(&drbd_cfg_rwsem);
- /* if this was the last volume of this connection,
- * this will terminate all threads */
- if (retcode == NO_ERROR)
- conn_reconfig_done(adm_ctx.tconn);
out:
drbd_adm_finish(info, retcode);
return 0;
@@ -3078,7 +3078,9 @@
/* delete connection */
if (conn_lowest_minor(adm_ctx.tconn) < 0) {
- drbd_free_tconn(adm_ctx.tconn);
+ list_del(&adm_ctx.tconn->all_tconn);
+ kref_put(&adm_ctx.tconn->kref, &conn_destroy);
+
retcode = NO_ERROR;
} else {
/* "can not happen" */
@@ -3107,7 +3109,9 @@
down_write(&drbd_cfg_rwsem);
if (conn_lowest_minor(adm_ctx.tconn) < 0) {
- drbd_free_tconn(adm_ctx.tconn);
+ list_del(&adm_ctx.tconn->all_tconn);
+ kref_put(&adm_ctx.tconn->kref, &conn_destroy);
+
retcode = NO_ERROR;
} else {
retcode = ERR_CONN_IN_USE;
diff --git a/drivers/block/drbd/drbd_state.c b/drivers/block/drbd/drbd_state.c
index f20a4a3..d7a330e 100644
--- a/drivers/block/drbd/drbd_state.c
+++ b/drivers/block/drbd/drbd_state.c
@@ -1460,6 +1460,7 @@
//conn_err(tconn, STATE_FMT, STATE_ARGS("nms", nms));
after_all_state_ch(tconn);
+ kref_put(&tconn->kref, &conn_destroy);
return 0;
}
@@ -1686,6 +1687,7 @@
acscw->ns_max = ns_max;
acscw->flags = flags;
acscw->w.cb = w_after_conn_state_ch;
+ kref_get(&tconn->kref);
acscw->w.tconn = tconn;
drbd_queue_work(&tconn->data.work, &acscw->w);
} else {