[PATCH net-next v3 02/10] net/smc: fix SMC_CLC_DECL_ERR_REGRMB without smc_server_lgr_pending

D.Wythe
2022-10-20T06:44:07Z

As commit 4940a1fdf31c ("net/smc: fix unexpected SMC_CLC_DECL_ERR_REGRMB
error cause by server") mentioned, it works only when all connection
creations are completely protected by smc_server_lgr_pending, since we
already remove this lock, we need to re-fix the issues.

Fixes: 4940a1fdf31c ("net/smc: fix unexpected SMC_CLC_DECL_ERR_REGRMB error cause by server")
Signed-off-by: D. Wythe <alibuda@linux.alibaba.com>
---
net/smc/af_smc.c | 2 ++
net/smc/smc_core.c | 11 ++++++++---
net/smc/smc_core.h | 19 +++++++++++++++++++
3 files changed, 29 insertions(+), 3 deletions(-)

diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index e369ab6..b55d9ad4 100644
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -2399,6 +2399,7 @@ static void smc_listen_work(struct work_struct *work)
if (rc)
goto out_decl;
}
+ smc_conn_leave_rtoken_pending(new_smc, ini);
smc_conn_save_peer_info(new_smc, cclc);
smc_listen_out_connected(new_smc);
SMC_STAT_SERV_SUCC_INC(sock_net(newclcsock->sk), ini);
@@ -2407,6 +2408,7 @@ static void smc_listen_work(struct work_struct *work)
goto out_free;

out_decl:
+ smc_conn_leave_rtoken_pending(new_smc, ini);
if (ini && ini->first_contact_local)
smc_lgr_decision_maker_on_first_contact_done(ini, false /* fail */);
smc_listen_decline(new_smc, rc, ini ? ini->first_contact_local : 0,
diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c
index 9530af3..041589a 100644
--- a/net/smc/smc_core.c
+++ b/net/smc/smc_core.c
@@ -2182,14 +2182,19 @@ int smc_conn_create(struct smc_sock *smc, struct smc_init_info *ini)
lgr->vlan_id == ini->vlan_id) &&
(role == SMC_CLNT || ini->is_smcd ||
(lgr->conns_num < SMC_RMBS_PER_LGR_MAX &&
- !bitmap_full(lgr->rtokens_used_mask, SMC_RMBS_PER_LGR_MAX)))) {
+ (SMC_RMBS_PER_LGR_MAX -
+ bitmap_weight(lgr->rtokens_used_mask, SMC_RMBS_PER_LGR_MAX)
+ > atomic_read(&lgr->rtoken_pendings))))) {
/* link group found */
ini->first_contact_local = 0;
conn->lgr = lgr;
rc = smc_lgr_register_conn(conn, false);
write_unlock_bh(&lgr->conns_lock);
- if (!rc && delayed_work_pending(&lgr->free_work))
- cancel_delayed_work(&lgr->free_work);
+ if (!rc) {
+ smc_conn_enter_rtoken_pending(smc, ini);
+ if (delayed_work_pending(&lgr->free_work))
+ cancel_delayed_work(&lgr->free_work);
+ }
break;
}
write_unlock_bh(&lgr->conns_lock);
diff --git a/net/smc/smc_core.h b/net/smc/smc_core.h
index ad22751..dae2983 100644
--- a/net/smc/smc_core.h
+++ b/net/smc/smc_core.h
@@ -253,6 +253,9 @@ struct smc_link_group {
struct rb_root conns_all; /* connection tree */
rwlock_t conns_lock; /* protects conns_all */
unsigned int conns_num; /* current # of connections */
+ atomic_t rtoken_pendings;/* number of connection that
+ * lgr assigned but no rtoken got yet
+ */
unsigned short vlan_id; /* vlan id of link group */

struct list_head sndbufs[SMC_RMBE_SIZES];/* tx buffers */
@@ -569,6 +572,22 @@ struct smc_link *smc_switch_conns(struct smc_link_group *lgr,

void smc_lgr_decision_maker_on_first_contact_done(struct smc_init_info *ini, bool success);

+static inline void smc_conn_enter_rtoken_pending(struct smc_sock *smc, struct smc_init_info *ini)
+{
+ struct smc_link_group *lgr = smc->conn.lgr;
+
+ if (lgr && !ini->first_contact_local)
+ atomic_inc(&lgr->rtoken_pendings);
+}
+
+static inline void smc_conn_leave_rtoken_pending(struct smc_sock *smc, struct smc_init_info *ini)
+{
+ struct smc_link_group *lgr = smc->conn.lgr;
+
+ if (lgr && !ini->first_contact_local)
+ atomic_dec(&lgr->rtoken_pendings);
+}
+
static inline struct smc_link_group *smc_get_lgr(struct smc_link *link)
{
return link->lgr;
--
1.8.3.1