[PATCH net-next 08/12] net/smc: asymmetric link tagging

Karsten Graul
2020-05-04T12:18:44Z

New connections must not be assigned to asymmetric links. Add asymmetric
link tagging using new link variable link_is_asym. The new helpers
smcr_lgr_set_type() and smcr_lgr_set_type_asym() are called to set the
state of the link group, and tag all links accordingly.
smcr_lgr_conn_assign_link() respects the link tagging and will not
assign new connections to links tagged as asymmetric link.

Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Reviewed-by: Ursula Braun <ubraun@linux.ibm.com>
---
net/smc/smc_core.c | 26 +++++++++++++++++++++++---
net/smc/smc_core.h | 4 ++++
net/smc/smc_llc.c | 20 ++++++++++++++------
3 files changed, 41 insertions(+), 9 deletions(-)

diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c
index 9c19b9aa3719..be15b30a1234 100644
--- a/net/smc/smc_core.c
+++ b/net/smc/smc_core.c
@@ -132,7 +132,7 @@ static int smcr_lgr_conn_assign_link(struct smc_connection *conn, bool first)
for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) {
struct smc_link *lnk = &conn->lgr->lnk[i];

- if (lnk->state != expected)
+ if (lnk->state != expected || lnk->link_is_asym)
continue;
if (conn->lgr->role == SMC_CLNT) {
conn->lnk = lnk; /* temporary, SMC server assigns link*/
@@ -143,7 +143,8 @@ static int smcr_lgr_conn_assign_link(struct smc_connection *conn, bool first)
struct smc_link *lnk2;

lnk2 = &conn->lgr->lnk[j];
- if (lnk2->state == expected) {
+ if (lnk2->state == expected &&
+ !lnk2->link_is_asym) {
conn->lnk = lnk2;
break;
}
@@ -1030,6 +1031,25 @@ void smc_smcr_terminate_all(struct smc_ib_device *smcibdev)
}
}

+/* set new lgr type and clear all asymmetric link tagging */
+void smcr_lgr_set_type(struct smc_link_group *lgr, enum smc_lgr_type new_type)
+{
+ int i;
+
+ for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++)
+ if (smc_link_usable(&lgr->lnk[i]))
+ lgr->lnk[i].link_is_asym = false;
+ lgr->type = new_type;
+}
+
+/* set new lgr type and tag a link as asymmetric */
+void smcr_lgr_set_type_asym(struct smc_link_group *lgr,
+ enum smc_lgr_type new_type, int asym_lnk_idx)
+{
+ smcr_lgr_set_type(lgr, new_type);
+ lgr->lnk[asym_lnk_idx].link_is_asym = true;
+}
+
/* abort connection, abort_work scheduled from tasklet context */
static void smc_conn_abort_work(struct work_struct *work)
{
@@ -1123,7 +1143,7 @@ static void smcr_link_down(struct smc_link *lnk)
smcr_link_clear(lnk);
return;
}
- lgr->type = SMC_LGR_SINGLE;
+ smcr_lgr_set_type(lgr, SMC_LGR_SINGLE);
del_link_id = lnk->link_id;

if (lgr->role == SMC_SERV) {
diff --git a/net/smc/smc_core.h b/net/smc/smc_core.h
index 86eebbadc8f6..6ed7ab6d89d5 100644
--- a/net/smc/smc_core.h
+++ b/net/smc/smc_core.h
@@ -117,6 +117,7 @@ struct smc_link {
u8 peer_gid[SMC_GID_SIZE]; /* gid of peer*/
u8 link_id; /* unique # within link group */
u8 link_idx; /* index in lgr link array */
+ u8 link_is_asym; /* is link asymmetric? */
struct smc_link_group *lgr; /* parent link group */
struct work_struct link_down_wrk; /* wrk to bring link down */

@@ -380,6 +381,9 @@ int smcr_link_init(struct smc_link_group *lgr, struct smc_link *lnk,
void smcr_link_clear(struct smc_link *lnk);
int smcr_buf_map_lgr(struct smc_link *lnk);
int smcr_buf_reg_lgr(struct smc_link *lnk);
+void smcr_lgr_set_type(struct smc_link_group *lgr, enum smc_lgr_type new_type);
+void smcr_lgr_set_type_asym(struct smc_link_group *lgr,
+ enum smc_lgr_type new_type, int asym_lnk_idx);
int smcr_link_reg_rmb(struct smc_link *link, struct smc_buf_desc *rmb_desc);
struct smc_link *smc_switch_conns(struct smc_link_group *lgr,
struct smc_link *from_lnk, bool is_dev_err);
diff --git a/net/smc/smc_llc.c b/net/smc/smc_llc.c
index 0ea7ad6188ae..f65b2aac6b52 100644
--- a/net/smc/smc_llc.c
+++ b/net/smc/smc_llc.c
@@ -796,7 +796,11 @@ static int smc_llc_cli_conf_link(struct smc_link *link,
return -ENOLINK;
}
smc_llc_link_active(link_new);
- lgr->type = lgr_new_t;
+ if (lgr_new_t == SMC_LGR_ASYMMETRIC_LOCAL ||
+ lgr_new_t == SMC_LGR_ASYMMETRIC_PEER)
+ smcr_lgr_set_type_asym(lgr, lgr_new_t, link_new->link_idx);
+ else
+ smcr_lgr_set_type(lgr, lgr_new_t);
return 0;
}

@@ -1038,7 +1042,11 @@ static int smc_llc_srv_conf_link(struct smc_link *link,
return -ENOLINK;
}
smc_llc_link_active(link_new);
- lgr->type = lgr_new_t;
+ if (lgr_new_t == SMC_LGR_ASYMMETRIC_LOCAL ||
+ lgr_new_t == SMC_LGR_ASYMMETRIC_PEER)
+ smcr_lgr_set_type_asym(lgr, lgr_new_t, link_new->link_idx);
+ else
+ smcr_lgr_set_type(lgr, lgr_new_t);
smc_llc_flow_qentry_del(&lgr->llc_flow_lcl);
return 0;
}
@@ -1223,9 +1231,9 @@ static void smc_llc_process_cli_delete_link(struct smc_link_group *lgr)
if (lnk_del == lnk_asym) {
/* expected deletion of asym link, don't change lgr state */
} else if (active_links == 1) {
- lgr->type = SMC_LGR_SINGLE;
+ smcr_lgr_set_type(lgr, SMC_LGR_SINGLE);
} else if (!active_links) {
- lgr->type = SMC_LGR_NONE;
+ smcr_lgr_set_type(lgr, SMC_LGR_NONE);
smc_lgr_terminate_sched(lgr);
}
out_unlock:
@@ -1314,9 +1322,9 @@ static void smc_llc_process_srv_delete_link(struct smc_link_group *lgr)

active_links = smc_llc_active_link_count(lgr);
if (active_links == 1) {
- lgr->type = SMC_LGR_SINGLE;
+ smcr_lgr_set_type(lgr, SMC_LGR_SINGLE);
} else if (!active_links) {
- lgr->type = SMC_LGR_NONE;
+ smcr_lgr_set_type(lgr, SMC_LGR_NONE);
smc_lgr_terminate_sched(lgr);
}

--
2.17.1