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net/smc: delete an asymmetric link as SMC server

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When a link group moved from asymmetric to symmetric state then the
dangling asymmetric link can be deleted. Add smc_llc_find_asym_link() to
find the respective link and add smc_llc_delete_asym_link() to delete
it.

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 2020-05-03 14:38:46 +02:00 committed by David S. Miller
parent 1551c95b61
commit c9a5d24303
3 changed files with 82 additions and 2 deletions
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81
net/smc/smc_llc.c
View File

@ -863,6 +863,85 @@ static void smc_llc_process_cli_add_link(struct smc_link_group *lgr)
mutex_unlock(&lgr->llc_conf_mutex);
}
/* find the asymmetric link when 3 links are established */
static struct smc_link *smc_llc_find_asym_link(struct smc_link_group *lgr)
{
int asym_idx = -ENOENT;
int i, j, k;
bool found;
/* determine asymmetric link */
found = false;
for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) {
for (j = i + 1; j < SMC_LINKS_PER_LGR_MAX; j++) {
if (!smc_link_usable(&lgr->lnk[i]) ||
!smc_link_usable(&lgr->lnk[j]))
continue;
if (!memcmp(lgr->lnk[i].gid, lgr->lnk[j].gid,
SMC_GID_SIZE)) {
found = true; /* asym_lnk is i or j */
break;
}
}
if (found)
break;
}
if (!found)
goto out; /* no asymmetric link */
for (k = 0; k < SMC_LINKS_PER_LGR_MAX; k++) {
if (!smc_link_usable(&lgr->lnk[k]))
continue;
if (k != i &&
!memcmp(lgr->lnk[i].peer_gid, lgr->lnk[k].peer_gid,
SMC_GID_SIZE)) {
asym_idx = i;
break;
}
if (k != j &&
!memcmp(lgr->lnk[j].peer_gid, lgr->lnk[k].peer_gid,
SMC_GID_SIZE)) {
asym_idx = j;
break;
}
}
out:
return (asym_idx < 0) ? NULL : &lgr->lnk[asym_idx];
}
static void smc_llc_delete_asym_link(struct smc_link_group *lgr)
{
struct smc_link *lnk_new = NULL, *lnk_asym;
struct smc_llc_qentry *qentry;
int rc;
lnk_asym = smc_llc_find_asym_link(lgr);
if (!lnk_asym)
return; /* no asymmetric link */
if (!smc_link_downing(&lnk_asym->state))
return;
/* tbd: lnk_new = smc_switch_conns(lgr, lnk_asym, false); */
smc_wr_tx_wait_no_pending_sends(lnk_asym);
if (!lnk_new)
goto out_free;
/* change flow type from ADD_LINK into DEL_LINK */
lgr->llc_flow_lcl.type = SMC_LLC_FLOW_DEL_LINK;
rc = smc_llc_send_delete_link(lnk_new, lnk_asym->link_id, SMC_LLC_REQ,
true, SMC_LLC_DEL_NO_ASYM_NEEDED);
if (rc) {
smcr_link_down_cond(lnk_new);
goto out_free;
}
qentry = smc_llc_wait(lgr, lnk_new, SMC_LLC_WAIT_TIME,
SMC_LLC_DELETE_LINK);
if (!qentry) {
smcr_link_down_cond(lnk_new);
goto out_free;
}
smc_llc_flow_qentry_del(&lgr->llc_flow_lcl);
out_free:
smcr_link_clear(lnk_asym);
}
static int smc_llc_srv_rkey_exchange(struct smc_link *link,
struct smc_link *link_new)
{
@ -1014,7 +1093,7 @@ static void smc_llc_process_srv_add_link(struct smc_link_group *lgr)
rc = smc_llc_srv_add_link(link);
if (!rc && lgr->type == SMC_LGR_SYMMETRIC) {
/* delete any asymmetric link */
/* tbd: smc_llc_delete_asym_link(lgr); */
smc_llc_delete_asym_link(lgr);
}
mutex_unlock(&lgr->llc_conf_mutex);
}

2
net/smc/smc_wr.c
View File

@ -61,7 +61,7 @@ static inline bool smc_wr_is_tx_pend(struct smc_link *link)
}
/* wait till all pending tx work requests on the given link are completed */
static inline int smc_wr_tx_wait_no_pending_sends(struct smc_link *link)
int smc_wr_tx_wait_no_pending_sends(struct smc_link *link)
{
if (wait_event_timeout(link->wr_tx_wait, !smc_wr_is_tx_pend(link),
SMC_WR_TX_WAIT_PENDING_TIME))

1
net/smc/smc_wr.h
View File

@ -106,6 +106,7 @@ void smc_wr_tx_dismiss_slots(struct smc_link *lnk, u8 wr_rx_hdr_type,
smc_wr_tx_filter filter,
smc_wr_tx_dismisser dismisser,
unsigned long data);
int smc_wr_tx_wait_no_pending_sends(struct smc_link *link);
int smc_wr_rx_register_handler(struct smc_wr_rx_handler *handler);
int smc_wr_rx_post_init(struct smc_link *link);