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https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
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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>
This commit is contained in:
Philipp Reisner
parent
44ed167da7
commit
91fd4dad64
@ -833,9 +833,8 @@ struct drbd_tconn { /* is a resource from the config file */
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unsigned long flags;
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struct net_conf *net_conf; /* content protected by rcu */
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atomic_t net_cnt; /* Users of net_conf */
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wait_queue_head_t net_cnt_wait;
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wait_queue_head_t ping_wait; /* Woken upon reception of a ping, and a state change */
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struct mutex net_conf_update; /* mutex for ready-copy-update of net_conf */
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wait_queue_head_t ping_wait; /* Woken upon reception of a ping, and a state change */
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struct res_opts res_opts;
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struct drbd_socket data; /* data/barrier/cstate/parameter packets */
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@ -1379,6 +1378,7 @@ extern void drbd_delete_device(struct drbd_conf *mdev);
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struct drbd_tconn *drbd_new_tconn(const char *name);
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extern void drbd_free_tconn(struct drbd_tconn *tconn);
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struct drbd_tconn *conn_by_name(const char *name);
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extern void conn_free_crypto(struct drbd_tconn *tconn);
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extern int proc_details;
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@ -1935,29 +1935,6 @@ static inline void _sub_unacked(struct drbd_conf *mdev, int n, const char *func,
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ERR_IF_CNT_IS_NEGATIVE(unacked_cnt, func, line);
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}
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static inline void put_net_conf(struct drbd_tconn *tconn)
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{
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if (atomic_dec_and_test(&tconn->net_cnt))
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wake_up(&tconn->net_cnt_wait);
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}
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/**
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* get_net_conf() - Increase ref count on mdev->tconn->net_conf; Returns 0 if nothing there
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* @mdev: DRBD device.
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*
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* You have to call put_net_conf() when finished working with mdev->tconn->net_conf.
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*/
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static inline int get_net_conf(struct drbd_tconn *tconn)
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{
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int have_net_conf;
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atomic_inc(&tconn->net_cnt);
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have_net_conf = tconn->cstate >= C_UNCONNECTED;
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if (!have_net_conf)
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put_net_conf(tconn);
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return have_net_conf;
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}
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/**
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* get_ldev() - Increase the ref count on mdev->ldev. Returns 0 if there is no ldev
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* @M: DRBD device.
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@ -2385,6 +2385,20 @@ static void drbd_free_socket(struct drbd_socket *socket)
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free_page((unsigned long) socket->rbuf);
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}
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void conn_free_crypto(struct drbd_tconn *tconn)
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{
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crypto_free_hash(tconn->cram_hmac_tfm);
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crypto_free_hash(tconn->integrity_w_tfm);
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crypto_free_hash(tconn->integrity_r_tfm);
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kfree(tconn->int_dig_in);
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kfree(tconn->int_dig_vv);
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tconn->cram_hmac_tfm = NULL;
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tconn->integrity_w_tfm = NULL;
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tconn->integrity_r_tfm = NULL;
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tconn->int_dig_in = NULL;
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tconn->int_dig_vv = NULL;
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}
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struct drbd_tconn *drbd_new_tconn(const char *name)
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{
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struct drbd_tconn *tconn;
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@ -2411,8 +2425,7 @@ struct drbd_tconn *drbd_new_tconn(const char *name)
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tconn->cstate = C_STANDALONE;
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mutex_init(&tconn->cstate_mutex);
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spin_lock_init(&tconn->req_lock);
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atomic_set(&tconn->net_cnt, 0);
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init_waitqueue_head(&tconn->net_cnt_wait);
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mutex_init(&tconn->net_conf_update);
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init_waitqueue_head(&tconn->ping_wait);
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idr_init(&tconn->volumes);
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@ -589,11 +589,12 @@ drbd_set_role(struct drbd_conf *mdev, enum drbd_role new_role, int force)
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put_ldev(mdev);
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}
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} else {
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rcu_read_lock();
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nc = rcu_dereference(mdev->tconn->net_conf);
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mutex_lock(&mdev->tconn->net_conf_update);
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nc = mdev->tconn->net_conf;
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if (nc)
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nc->want_lose = 0;
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rcu_read_unlock();
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nc->want_lose = 0; /* without copy; single bit op is atomic */
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mutex_unlock(&mdev->tconn->net_conf_update);
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set_disk_ro(mdev->vdisk, false);
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if (get_ldev(mdev)) {
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if (((mdev->state.conn < C_CONNECTED ||
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@ -1760,17 +1761,16 @@ int drbd_adm_net_opts(struct sk_buff *skb, struct genl_info *info)
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conn_reconfig_start(tconn);
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rcu_read_lock();
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old_conf = rcu_dereference(tconn->net_conf);
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mutex_lock(&tconn->net_conf_update);
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old_conf = tconn->net_conf;
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if (!old_conf) {
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drbd_msg_put_info("net conf missing, try connect");
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retcode = ERR_INVALID_REQUEST;
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goto fail_rcu_unlock;
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goto fail;
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}
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*new_conf = *old_conf;
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rcu_read_unlock();
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err = net_conf_from_attrs_for_change(new_conf, info);
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if (err) {
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@ -1785,13 +1785,10 @@ int drbd_adm_net_opts(struct sk_buff *skb, struct genl_info *info)
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/* re-sync running */
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rsr = conn_resync_running(tconn);
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rcu_read_lock();
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old_conf = rcu_dereference(tconn->net_conf);
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if (rsr && old_conf && strcmp(new_conf->csums_alg, old_conf->csums_alg)) {
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retcode = ERR_CSUMS_RESYNC_RUNNING;
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goto fail_rcu_unlock;
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goto fail;
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}
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rcu_read_unlock();
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if (!rsr && new_conf->csums_alg[0]) {
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csums_tfm = crypto_alloc_hash(new_conf->csums_alg, 0, CRYPTO_ALG_ASYNC);
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@ -1809,15 +1806,12 @@ int drbd_adm_net_opts(struct sk_buff *skb, struct genl_info *info)
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/* online verify running */
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ovr = conn_ov_running(tconn);
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rcu_read_lock();
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old_conf = rcu_dereference(tconn->net_conf);
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if (ovr && old_conf) {
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if (ovr) {
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if (strcmp(new_conf->verify_alg, old_conf->verify_alg)) {
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retcode = ERR_VERIFY_RUNNING;
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goto fail_rcu_unlock;
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goto fail;
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}
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}
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rcu_read_unlock();
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if (!ovr && new_conf->verify_alg[0]) {
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verify_tfm = crypto_alloc_hash(new_conf->verify_alg, 0, CRYPTO_ALG_ASYNC);
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@ -1834,8 +1828,6 @@ int drbd_adm_net_opts(struct sk_buff *skb, struct genl_info *info)
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}
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rcu_assign_pointer(tconn->net_conf, new_conf);
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synchronize_rcu();
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kfree(old_conf);
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if (!rsr) {
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crypto_free_hash(tconn->csums_tfm);
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@ -1848,15 +1840,21 @@ int drbd_adm_net_opts(struct sk_buff *skb, struct genl_info *info)
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verify_tfm = NULL;
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}
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mutex_unlock(&tconn->net_conf_update);
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synchronize_rcu();
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kfree(old_conf);
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if (tconn->cstate >= C_WF_REPORT_PARAMS)
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drbd_send_sync_param(minor_to_mdev(conn_lowest_minor(tconn)));
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fail_rcu_unlock:
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rcu_read_unlock();
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goto done;
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fail:
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mutex_unlock(&tconn->net_conf_update);
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crypto_free_hash(csums_tfm);
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crypto_free_hash(verify_tfm);
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kfree(new_conf);
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done:
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conn_reconfig_done(tconn);
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out:
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drbd_adm_finish(info, retcode);
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@ -2032,32 +2030,26 @@ int drbd_adm_connect(struct sk_buff *skb, struct genl_info *info)
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}
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conn_flush_workqueue(tconn);
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spin_lock_irq(&tconn->req_lock);
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rcu_read_lock();
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old_conf = rcu_dereference(tconn->net_conf);
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if (old_conf != NULL) {
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mutex_lock(&tconn->net_conf_update);
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old_conf = tconn->net_conf;
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if (old_conf) {
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retcode = ERR_NET_CONFIGURED;
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rcu_read_unlock();
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spin_unlock_irq(&tconn->req_lock);
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mutex_unlock(&tconn->net_conf_update);
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goto fail;
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}
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rcu_assign_pointer(tconn->net_conf, new_conf);
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crypto_free_hash(tconn->cram_hmac_tfm);
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conn_free_crypto(tconn);
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tconn->cram_hmac_tfm = tfm;
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crypto_free_hash(tconn->integrity_w_tfm);
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tconn->integrity_w_tfm = integrity_w_tfm;
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crypto_free_hash(tconn->integrity_r_tfm);
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tconn->integrity_r_tfm = integrity_r_tfm;
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tconn->int_dig_in = int_dig_in;
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tconn->int_dig_vv = int_dig_vv;
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kfree(tconn->int_dig_in);
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kfree(tconn->int_dig_vv);
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tconn->int_dig_in=int_dig_in;
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tconn->int_dig_vv=int_dig_vv;
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retcode = _conn_request_state(tconn, NS(conn, C_UNCONNECTED), CS_VERBOSE);
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spin_unlock_irq(&tconn->req_lock);
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mutex_unlock(&tconn->net_conf_update);
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retcode = conn_request_state(tconn, NS(conn, C_UNCONNECTED), CS_VERBOSE);
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rcu_read_lock();
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idr_for_each_entry(&tconn->volumes, mdev, i) {
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@ -3138,6 +3138,7 @@ static int receive_SyncParam(struct drbd_tconn *tconn, struct packet_info *pi)
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unsigned int header_size, data_size, exp_max_sz;
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struct crypto_hash *verify_tfm = NULL;
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struct crypto_hash *csums_tfm = NULL;
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struct net_conf *old_conf, *new_conf = NULL;
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const int apv = tconn->agreed_pro_version;
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int *rs_plan_s = NULL;
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int fifo_size = 0;
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@ -3212,10 +3213,13 @@ static int receive_SyncParam(struct drbd_tconn *tconn, struct packet_info *pi)
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p->csums_alg[SHARED_SECRET_MAX-1] = 0;
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}
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if (strcmp(mdev->tconn->net_conf->verify_alg, p->verify_alg)) {
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mutex_lock(&mdev->tconn->net_conf_update);
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old_conf = mdev->tconn->net_conf;
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if (strcmp(old_conf->verify_alg, p->verify_alg)) {
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if (mdev->state.conn == C_WF_REPORT_PARAMS) {
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dev_err(DEV, "Different verify-alg settings. me=\"%s\" peer=\"%s\"\n",
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mdev->tconn->net_conf->verify_alg, p->verify_alg);
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old_conf->verify_alg, p->verify_alg);
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goto disconnect;
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}
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verify_tfm = drbd_crypto_alloc_digest_safe(mdev,
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@ -3226,10 +3230,10 @@ static int receive_SyncParam(struct drbd_tconn *tconn, struct packet_info *pi)
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}
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}
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if (apv >= 89 && strcmp(mdev->tconn->net_conf->csums_alg, p->csums_alg)) {
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if (apv >= 89 && strcmp(old_conf->csums_alg, p->csums_alg)) {
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if (mdev->state.conn == C_WF_REPORT_PARAMS) {
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dev_err(DEV, "Different csums-alg settings. me=\"%s\" peer=\"%s\"\n",
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mdev->tconn->net_conf->csums_alg, p->csums_alg);
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old_conf->csums_alg, p->csums_alg);
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goto disconnect;
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}
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csums_tfm = drbd_crypto_alloc_digest_safe(mdev,
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@ -3259,22 +3263,38 @@ static int receive_SyncParam(struct drbd_tconn *tconn, struct packet_info *pi)
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put_ldev(mdev);
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}
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if (verify_tfm || csums_tfm) {
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new_conf = kzalloc(sizeof(struct net_conf), GFP_KERNEL);
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if (!new_conf) {
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dev_err(DEV, "Allocation of new net_conf failed\n");
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goto disconnect;
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}
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*new_conf = *old_conf;
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if (verify_tfm) {
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strcpy(new_conf->verify_alg, p->verify_alg);
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new_conf->verify_alg_len = strlen(p->verify_alg) + 1;
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crypto_free_hash(mdev->tconn->verify_tfm);
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mdev->tconn->verify_tfm = verify_tfm;
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dev_info(DEV, "using verify-alg: \"%s\"\n", p->verify_alg);
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}
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if (csums_tfm) {
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strcpy(new_conf->csums_alg, p->csums_alg);
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new_conf->csums_alg_len = strlen(p->csums_alg) + 1;
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crypto_free_hash(mdev->tconn->csums_tfm);
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mdev->tconn->csums_tfm = csums_tfm;
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dev_info(DEV, "using csums-alg: \"%s\"\n", p->csums_alg);
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}
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rcu_assign_pointer(tconn->net_conf, new_conf);
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}
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mutex_unlock(&mdev->tconn->net_conf_update);
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if (new_conf) {
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synchronize_rcu();
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kfree(old_conf);
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}
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spin_lock(&mdev->peer_seq_lock);
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/* lock against drbd_nl_syncer_conf() */
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if (verify_tfm) {
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strcpy(mdev->tconn->net_conf->verify_alg, p->verify_alg);
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mdev->tconn->net_conf->verify_alg_len = strlen(p->verify_alg) + 1;
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crypto_free_hash(mdev->tconn->verify_tfm);
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mdev->tconn->verify_tfm = verify_tfm;
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dev_info(DEV, "using verify-alg: \"%s\"\n", p->verify_alg);
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}
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if (csums_tfm) {
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strcpy(mdev->tconn->net_conf->csums_alg, p->csums_alg);
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mdev->tconn->net_conf->csums_alg_len = strlen(p->csums_alg) + 1;
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crypto_free_hash(mdev->tconn->csums_tfm);
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mdev->tconn->csums_tfm = csums_tfm;
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dev_info(DEV, "using csums-alg: \"%s\"\n", p->csums_alg);
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}
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if (fifo_size != mdev->rs_plan_s.size) {
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kfree(mdev->rs_plan_s.values);
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mdev->rs_plan_s.values = rs_plan_s;
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@ -3286,6 +3306,7 @@ static int receive_SyncParam(struct drbd_tconn *tconn, struct packet_info *pi)
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return 0;
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disconnect:
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mutex_unlock(&mdev->tconn->net_conf_update);
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/* just for completeness: actually not needed,
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* as this is not reached if csums_tfm was ok. */
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crypto_free_hash(csums_tfm);
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@ -3715,7 +3736,9 @@ static int receive_state(struct drbd_tconn *tconn, struct packet_info *pi)
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}
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}
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mdev->tconn->net_conf->want_lose = 0;
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mutex_lock(&mdev->tconn->net_conf_update);
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mdev->tconn->net_conf->want_lose = 0; /* without copy; single bit op is atomic */
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mutex_unlock(&mdev->tconn->net_conf_update);
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drbd_md_sync(mdev); /* update connected indicator, la_size, ... */
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@ -4183,13 +4206,17 @@ static void drbd_disconnect(struct drbd_tconn *tconn)
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spin_unlock_irq(&tconn->req_lock);
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if (oc == C_DISCONNECTING) {
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wait_event(tconn->net_cnt_wait, atomic_read(&tconn->net_cnt) == 0);
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struct net_conf *old_conf;
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crypto_free_hash(tconn->cram_hmac_tfm);
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tconn->cram_hmac_tfm = NULL;
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mutex_lock(&tconn->net_conf_update);
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old_conf = tconn->net_conf;
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rcu_assign_pointer(tconn->net_conf, NULL);
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conn_free_crypto(tconn);
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mutex_unlock(&tconn->net_conf_update);
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synchronize_rcu();
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kfree(old_conf);
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kfree(tconn->net_conf);
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tconn->net_conf = NULL;
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conn_request_state(tconn, NS(conn, C_STANDALONE), CS_VERBOSE);
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}
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}
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@ -4568,12 +4595,8 @@ int drbdd_init(struct drbd_thread *thi)
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}
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} while (h == 0);
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if (h > 0) {
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if (get_net_conf(tconn)) {
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drbdd(tconn);
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put_net_conf(tconn);
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}
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}
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if (h > 0)
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drbdd(tconn);
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drbd_disconnect(tconn);
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