drbd: Proper locking for updates to net_conf under RCU
Removing the get_net_conf()/put_net_conf() functions
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_nl.c b/drivers/block/drbd/drbd_nl.c
index 34be842..f86e882 100644
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -589,11 +589,12 @@
put_ldev(mdev);
}
} else {
- rcu_read_lock();
- nc = rcu_dereference(mdev->tconn->net_conf);
+ mutex_lock(&mdev->tconn->net_conf_update);
+ nc = mdev->tconn->net_conf;
if (nc)
- nc->want_lose = 0;
- rcu_read_unlock();
+ nc->want_lose = 0; /* without copy; single bit op is atomic */
+ mutex_unlock(&mdev->tconn->net_conf_update);
+
set_disk_ro(mdev->vdisk, false);
if (get_ldev(mdev)) {
if (((mdev->state.conn < C_CONNECTED ||
@@ -1760,17 +1761,16 @@
conn_reconfig_start(tconn);
- rcu_read_lock();
- old_conf = rcu_dereference(tconn->net_conf);
+ mutex_lock(&tconn->net_conf_update);
+ old_conf = tconn->net_conf;
if (!old_conf) {
drbd_msg_put_info("net conf missing, try connect");
retcode = ERR_INVALID_REQUEST;
- goto fail_rcu_unlock;
+ goto fail;
}
*new_conf = *old_conf;
- rcu_read_unlock();
err = net_conf_from_attrs_for_change(new_conf, info);
if (err) {
@@ -1785,13 +1785,10 @@
/* re-sync running */
rsr = conn_resync_running(tconn);
- rcu_read_lock();
- old_conf = rcu_dereference(tconn->net_conf);
if (rsr && old_conf && strcmp(new_conf->csums_alg, old_conf->csums_alg)) {
retcode = ERR_CSUMS_RESYNC_RUNNING;
- goto fail_rcu_unlock;
+ goto fail;
}
- rcu_read_unlock();
if (!rsr && new_conf->csums_alg[0]) {
csums_tfm = crypto_alloc_hash(new_conf->csums_alg, 0, CRYPTO_ALG_ASYNC);
@@ -1809,15 +1806,12 @@
/* online verify running */
ovr = conn_ov_running(tconn);
- rcu_read_lock();
- old_conf = rcu_dereference(tconn->net_conf);
- if (ovr && old_conf) {
+ if (ovr) {
if (strcmp(new_conf->verify_alg, old_conf->verify_alg)) {
retcode = ERR_VERIFY_RUNNING;
- goto fail_rcu_unlock;
+ goto fail;
}
}
- rcu_read_unlock();
if (!ovr && new_conf->verify_alg[0]) {
verify_tfm = crypto_alloc_hash(new_conf->verify_alg, 0, CRYPTO_ALG_ASYNC);
@@ -1834,8 +1828,6 @@
}
rcu_assign_pointer(tconn->net_conf, new_conf);
- synchronize_rcu();
- kfree(old_conf);
if (!rsr) {
crypto_free_hash(tconn->csums_tfm);
@@ -1848,15 +1840,21 @@
verify_tfm = NULL;
}
+ mutex_unlock(&tconn->net_conf_update);
+ synchronize_rcu();
+ kfree(old_conf);
+
if (tconn->cstate >= C_WF_REPORT_PARAMS)
drbd_send_sync_param(minor_to_mdev(conn_lowest_minor(tconn)));
- fail_rcu_unlock:
- rcu_read_unlock();
+ goto done;
+
fail:
+ mutex_unlock(&tconn->net_conf_update);
crypto_free_hash(csums_tfm);
crypto_free_hash(verify_tfm);
kfree(new_conf);
+ done:
conn_reconfig_done(tconn);
out:
drbd_adm_finish(info, retcode);
@@ -2032,32 +2030,26 @@
}
conn_flush_workqueue(tconn);
- spin_lock_irq(&tconn->req_lock);
- rcu_read_lock();
- old_conf = rcu_dereference(tconn->net_conf);
- if (old_conf != NULL) {
+
+ mutex_lock(&tconn->net_conf_update);
+ old_conf = tconn->net_conf;
+ if (old_conf) {
retcode = ERR_NET_CONFIGURED;
- rcu_read_unlock();
- spin_unlock_irq(&tconn->req_lock);
+ mutex_unlock(&tconn->net_conf_update);
goto fail;
}
rcu_assign_pointer(tconn->net_conf, new_conf);
- crypto_free_hash(tconn->cram_hmac_tfm);
+ conn_free_crypto(tconn);
tconn->cram_hmac_tfm = tfm;
-
- crypto_free_hash(tconn->integrity_w_tfm);
tconn->integrity_w_tfm = integrity_w_tfm;
-
- crypto_free_hash(tconn->integrity_r_tfm);
tconn->integrity_r_tfm = integrity_r_tfm;
+ tconn->int_dig_in = int_dig_in;
+ tconn->int_dig_vv = int_dig_vv;
- kfree(tconn->int_dig_in);
- kfree(tconn->int_dig_vv);
- tconn->int_dig_in=int_dig_in;
- tconn->int_dig_vv=int_dig_vv;
- retcode = _conn_request_state(tconn, NS(conn, C_UNCONNECTED), CS_VERBOSE);
- spin_unlock_irq(&tconn->req_lock);
+ mutex_unlock(&tconn->net_conf_update);
+
+ retcode = conn_request_state(tconn, NS(conn, C_UNCONNECTED), CS_VERBOSE);
rcu_read_lock();
idr_for_each_entry(&tconn->volumes, mdev, i) {