drbd: Converted drbd_cfg_mutex into drbd_cfg_rwsem
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 c49dc08..7896a64 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -171,7 +171,9 @@
extern struct ratelimit_state drbd_ratelimit_state;
extern struct idr minors;
extern struct list_head drbd_tconns;
-extern struct mutex drbd_cfg_mutex;
+extern struct rw_semaphore drbd_cfg_rwsem;
+/* drbd_cfg_rwsem protects: drbd_tconns list,
+ note: non sleeping iterations over the idrs are protoected by RCU */
/* on the wire */
enum drbd_packet {
diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index 5abbdaf..86fd4c8 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -120,7 +120,7 @@
*/
struct idr minors;
struct list_head drbd_tconns; /* list of struct drbd_tconn */
-DEFINE_MUTEX(drbd_cfg_mutex);
+DECLARE_RWSEM(drbd_cfg_rwsem);
struct kmem_cache *drbd_request_cache;
struct kmem_cache *drbd_ee_cache; /* peer requests */
@@ -2330,14 +2330,14 @@
if (!name || !name[0])
return NULL;
- mutex_lock(&drbd_cfg_mutex);
+ down_read(&drbd_cfg_rwsem);
list_for_each_entry(tconn, &drbd_tconns, all_tconn) {
if (!strcmp(tconn->name, name))
goto found;
}
tconn = NULL;
found:
- mutex_unlock(&drbd_cfg_mutex);
+ up_read(&drbd_cfg_rwsem);
return tconn;
}
@@ -2404,9 +2404,9 @@
DRBD_ON_NO_DATA_DEF, /* on_no_data */
};
- mutex_lock(&drbd_cfg_mutex);
+ down_write(&drbd_cfg_rwsem);
list_add_tail(&tconn->all_tconn, &drbd_tconns);
- mutex_unlock(&drbd_cfg_mutex);
+ up_write(&drbd_cfg_rwsem);
return tconn;
diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index 60c171b..424dcb3 100644
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -1905,7 +1905,7 @@
new_my_addr = (struct sockaddr *)&new_conf->my_addr;
new_peer_addr = (struct sockaddr *)&new_conf->peer_addr;
- /* No need to take drbd_cfg_mutex here. All reconfiguration is
+ /* No need to take drbd_cfg_rwsem here. All reconfiguration is
* strictly serialized on genl_lock(). We are protected against
* concurrent reconfiguration/addition/deletion */
list_for_each_entry(oconn, &drbd_tconns, all_tconn) {
@@ -2581,7 +2581,7 @@
*/
/* synchronize with drbd_new_tconn/drbd_free_tconn */
- mutex_lock(&drbd_cfg_mutex);
+ down_read(&drbd_cfg_rwsem);
next_tconn:
/* revalidate iterator position */
list_for_each_entry(tmp, &drbd_tconns, all_tconn) {
@@ -2642,7 +2642,7 @@
}
out:
- mutex_unlock(&drbd_cfg_mutex);
+ up_read(&drbd_cfg_rwsem);
/* where to start the next iteration */
cb->args[0] = (long)pos;
cb->args[1] = (pos == tconn) ? volume + 1 : 0;
@@ -2894,9 +2894,9 @@
if (retcode != NO_ERROR)
goto out;
- mutex_lock(&drbd_cfg_mutex);
+ down_write(&drbd_cfg_rwsem);
retcode = adm_delete_minor(adm_ctx.mdev);
- mutex_unlock(&drbd_cfg_mutex);
+ up_write(&drbd_cfg_rwsem);
/* if this was the last volume of this connection,
* this will terminate all threads */
if (retcode == NO_ERROR)
@@ -2924,7 +2924,7 @@
goto out;
}
- mutex_lock(&drbd_cfg_mutex);
+ down_read(&drbd_cfg_rwsem);
/* demote */
idr_for_each_entry(&adm_ctx.tconn->volumes, mdev, i) {
retcode = drbd_set_role(mdev, R_SECONDARY, 0);
@@ -2951,14 +2951,17 @@
goto out_unlock;
}
}
+ up_read(&drbd_cfg_rwsem);
/* delete volumes */
+ down_write(&drbd_cfg_rwsem);
idr_for_each_entry(&adm_ctx.tconn->volumes, mdev, i) {
retcode = adm_delete_minor(mdev);
if (retcode != NO_ERROR) {
/* "can not happen" */
drbd_msg_put_info("failed to delete volume");
- goto out_unlock;
+ up_write(&drbd_cfg_rwsem);
+ goto out;
}
}
@@ -2973,10 +2976,12 @@
/* "can not happen" */
retcode = ERR_CONN_IN_USE;
drbd_msg_put_info("failed to delete connection");
- goto out_unlock;
}
+
+ up_write(&drbd_cfg_rwsem);
+ goto out;
out_unlock:
- mutex_unlock(&drbd_cfg_mutex);
+ up_read(&drbd_cfg_rwsem);
out:
drbd_adm_finish(info, retcode);
return 0;
@@ -2992,14 +2997,14 @@
if (retcode != NO_ERROR)
goto out;
- mutex_lock(&drbd_cfg_mutex);
+ down_write(&drbd_cfg_rwsem);
if (conn_lowest_minor(adm_ctx.tconn) < 0) {
drbd_free_tconn(adm_ctx.tconn);
retcode = NO_ERROR;
} else {
retcode = ERR_CONN_IN_USE;
}
- mutex_unlock(&drbd_cfg_mutex);
+ up_write(&drbd_cfg_rwsem);
out:
drbd_adm_finish(info, retcode);