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net/smc: assign link to a new connection 

For new connections, assign a link from the link group, using some
simple load balancing.

Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Reviewed-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Karsten Graul 2020-05-04 14:18:43 +02:00 committed by David S. Miller
parent f3811fd7bc
commit 56bc3b2094
1 changed files with 46 additions and 19 deletions
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65
net/smc/smc_core.c
View File

@ -121,16 +121,59 @@ static void smc_lgr_add_alert_token(struct smc_connection *conn)
rb_insert_color(&conn->alert_node, &conn->lgr->conns_all);
}
/* assign an SMC-R link to the connection */
static int smcr_lgr_conn_assign_link(struct smc_connection *conn, bool first)
{
enum smc_link_state expected = first ? SMC_LNK_ACTIVATING :
SMC_LNK_ACTIVE;
int i, j;
/* do link balancing */
for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) {
struct smc_link *lnk = &conn->lgr->lnk[i];
if (lnk->state != expected)
continue;
if (conn->lgr->role == SMC_CLNT) {
conn->lnk = lnk; /* temporary, SMC server assigns link*/
break;
}
if (conn->lgr->conns_num % 2) {
for (j = i + 1; j < SMC_LINKS_PER_LGR_MAX; j++) {
struct smc_link *lnk2;
lnk2 = &conn->lgr->lnk[j];
if (lnk2->state == expected) {
conn->lnk = lnk2;
break;
}
}
}
if (!conn->lnk)
conn->lnk = lnk;
break;
}
if (!conn->lnk)
return SMC_CLC_DECL_NOACTLINK;
return 0;
}
/* Register connection in link group by assigning an alert token
* registered in a search tree.
* Requires @conns_lock
* Note that '0' is a reserved value and not assigned.
*/
static int smc_lgr_register_conn(struct smc_connection *conn)
static int smc_lgr_register_conn(struct smc_connection *conn, bool first)
{
struct smc_sock *smc = container_of(conn, struct smc_sock, conn);
static atomic_t nexttoken = ATOMIC_INIT(0);
int rc;
if (!conn->lgr->is_smcd) {
rc = smcr_lgr_conn_assign_link(conn, first);
if (rc)
return rc;
}
/* find a new alert_token_local value not yet used by some connection
* in this link group
*/
@ -141,22 +184,6 @@ static int smc_lgr_register_conn(struct smc_connection *conn)
conn->alert_token_local = 0;
}
smc_lgr_add_alert_token(conn);
/* assign the new connection to a link */
if (!conn->lgr->is_smcd) {
struct smc_link *lnk;
int i;
/* tbd - link balancing */
for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) {
lnk = &conn->lgr->lnk[i];
if (lnk->state == SMC_LNK_ACTIVATING ||
lnk->state == SMC_LNK_ACTIVE)
conn->lnk = lnk;
}
if (!conn->lnk)
return SMC_CLC_DECL_NOACTLINK;
}
conn->lgr->conns_num++;
return 0;
}
@ -1285,7 +1312,7 @@ int smc_conn_create(struct smc_sock *smc, struct smc_init_info *ini)
/* link group found */
ini->cln_first_contact = SMC_REUSE_CONTACT;
conn->lgr = lgr;
rc = smc_lgr_register_conn(conn); /* add conn to 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);
@ -1313,7 +1340,7 @@ create:
goto out;
lgr = conn->lgr;
write_lock_bh(&lgr->conns_lock);
rc = smc_lgr_register_conn(conn); /* add smc conn to lgr */
rc = smc_lgr_register_conn(conn, true);
write_unlock_bh(&lgr->conns_lock);
if (rc)
goto out;