net/smc: keep static copy of system EID

The system EID is retrieved using an registered ISM device each time
when needed. This adds some unnecessary complexity at all places where
the system EID is needed, but no ISM device is at hand.
Simplify the code and save the system EID in a static variable in
smc_ism.c.
Signed-off-by: NKarsten Graul <kgraul@linux.ibm.com>
Reviewed-by: NGuvenc Gulce  <guvenc@linux.ibm.com>
Signed-off-by: NGuvenc Gulce <guvenc@linux.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/smc/af_smc.c

@@ -1565,7 +1565,7 @@ static void smc_find_ism_v2_device_serv(struct smc_sock *new_smc,
 	if (!ini->ism_dev[0])
 		goto not_found;
 
-	smc_ism_get_system_eid(ini->ism_dev[0], &eid);
+	smc_ism_get_system_eid(&eid);
 	if (!smc_clc_match_eid(ini->negotiated_eid, smc_v2_ext,
 			       smcd_v2_ext->system_eid, eid))
 		goto not_found;

net/smc/smc_clc.c

@@ -796,10 +796,7 @@ int smc_clc_send_proposal(struct smc_sock *smc, struct smc_init_info *ini)
 				offsetofend(struct smc_clnt_opts_area_hdr,
 					    smcd_v2_ext_offset) +
 				v2_ext->hdr.eid_cnt * SMC_MAX_EID_LEN);
-		if (ini->ism_dev[0])
-			smc_ism_get_system_eid(ini->ism_dev[0], &eid);
-		else
-			smc_ism_get_system_eid(ini->ism_dev[1], &eid);
+		smc_ism_get_system_eid(&eid);
 		if (eid && v2_ext->hdr.flag.seid)
 			memcpy(smcd_v2_ext->system_eid, eid, SMC_MAX_EID_LEN);
 		plen += sizeof(*v2_ext) + sizeof(*smcd_v2_ext);

net/smc/smc_core.c

@@ -223,7 +223,6 @@ int smc_nl_get_sys_info(struct sk_buff *skb, struct netlink_callback *cb)
 	struct smc_nl_dmp_ctx *cb_ctx = smc_nl_dmp_ctx(cb);
 	char hostname[SMC_MAX_HOSTNAME_LEN + 1];
 	char smc_seid[SMC_MAX_EID_LEN + 1];
-	struct smcd_dev *smcd_dev;
 	struct nlattr *attrs;
 	u8 *seid = NULL;
 	u8 *host = NULL;
@@ -252,13 +251,8 @@ int smc_nl_get_sys_info(struct sk_buff *skb, struct netlink_callback *cb)
 		if (nla_put_string(skb, SMC_NLA_SYS_LOCAL_HOST, hostname))
 			goto errattr;
 	}
-	mutex_lock(&smcd_dev_list.mutex);
-	smcd_dev = list_first_entry_or_null(&smcd_dev_list.list,
-					    struct smcd_dev, list);
-	if (smcd_dev)
-		smc_ism_get_system_eid(smcd_dev, &seid);
-	mutex_unlock(&smcd_dev_list.mutex);
-	if (seid && smc_ism_is_v2_capable()) {
+	if (smc_ism_is_v2_capable()) {
+		smc_ism_get_system_eid(&seid);
 		memcpy(smc_seid, seid, SMC_MAX_EID_LEN);
 		smc_seid[SMC_MAX_EID_LEN] = 0;
 		if (nla_put_string(skb, SMC_NLA_SYS_SEID, smc_seid))

net/smc/smc_ism.c

@@ -23,6 +23,7 @@ struct smcd_dev_list smcd_dev_list = {
 };
 
 static bool smc_ism_v2_capable;
+static u8 smc_ism_v2_system_eid[SMC_MAX_EID_LEN];
 
 /* Test if an ISM communication is possible - same CPC */
 int smc_ism_cantalk(u64 peer_gid, unsigned short vlan_id, struct smcd_dev *smcd)
@@ -42,9 +43,12 @@ int smc_ism_write(struct smcd_dev *smcd, const struct smc_ism_position *pos,
 	return rc < 0 ? rc : 0;
 }
 
-void smc_ism_get_system_eid(struct smcd_dev *smcd, u8 **eid)
+void smc_ism_get_system_eid(u8 **eid)
 {
-	smcd->ops->get_system_eid(smcd, eid);
+	if (!smc_ism_v2_capable)
+		*eid = NULL;
+	else
+		*eid = smc_ism_v2_system_eid;
 }
 
 u16 smc_ism_get_chid(struct smcd_dev *smcd)
@@ -435,9 +439,12 @@ int smcd_register_dev(struct smcd_dev *smcd)
 	if (list_empty(&smcd_dev_list.list)) {
 		u8 *system_eid = NULL;
 
-		smc_ism_get_system_eid(smcd, &system_eid);
-		if (system_eid[24] != '0' || system_eid[28] != '0')
+		smcd->ops->get_system_eid(smcd, &system_eid);
+		if (system_eid[24] != '0' || system_eid[28] != '0') {
 			smc_ism_v2_capable = true;
+			memcpy(smc_ism_v2_system_eid, system_eid,
+			       SMC_MAX_EID_LEN);
+		}
 	}
 	/* sort list: devices without pnetid before devices with pnetid */
 	if (smcd->pnetid[0])
@@ -533,4 +540,5 @@ EXPORT_SYMBOL_GPL(smcd_handle_irq);
 void __init smc_ism_init(void)
 {
 	smc_ism_v2_capable = false;
+	memset(smc_ism_v2_system_eid, 0, SMC_MAX_EID_LEN);
 }

net/smc/smc_ism.h

@@ -48,7 +48,7 @@ int smc_ism_unregister_dmb(struct smcd_dev *dev, struct smc_buf_desc *dmb_desc);
 int smc_ism_write(struct smcd_dev *dev, const struct smc_ism_position *pos,
 		  void *data, size_t len);
 int smc_ism_signal_shutdown(struct smc_link_group *lgr);
-void smc_ism_get_system_eid(struct smcd_dev *dev, u8 **eid);
+void smc_ism_get_system_eid(u8 **eid);
 u16 smc_ism_get_chid(struct smcd_dev *dev);
 bool smc_ism_is_v2_capable(void);
 void smc_ism_init(void);