[PATCH net-next 10/12] net/smc: improve termination processing

Karsten Graul
2020-05-04T12:19:16Z

Add helper smcr_lgr_link_deactivate_all() and eliminate duplicate code.
In smc_lgr_free(), clear the smc-r links before smc_lgr_free_bufs() is
called so buffers are already prepared for free. The usage of the soft
parameter in __smc_lgr_terminate() is no longer needed, smc_lgr_free()
can be called directly. smc_lgr_terminate_sched() and
smc_smcd_terminate() set lgr->freeing to indicate that the link group
will be freed soon to avoid unnecessary schedules of the free worker.

Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Reviewed-by: Ursula Braun <ubraun@linux.ibm.com>
---
net/smc/smc_core.c | 61 +++++++++++++++++++++++-----------------------
1 file changed, 31 insertions(+), 30 deletions(-)

diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c
index b6f93b44f9c7..fb391bc6781e 100644
--- a/net/smc/smc_core.c
+++ b/net/smc/smc_core.c
@@ -237,6 +237,19 @@ void smc_lgr_cleanup_early(struct smc_connection *conn)
smc_lgr_schedule_free_work_fast(lgr);
}

+static void smcr_lgr_link_deactivate_all(struct smc_link_group *lgr)
+{
+ int i;
+
+ for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) {
+ struct smc_link *lnk = &lgr->lnk[i];
+
+ if (smc_link_usable(lnk))
+ lnk->state = SMC_LNK_INACTIVE;
+ }
+ wake_up_interruptible_all(&lgr->llc_waiter);
+}
+
static void smc_lgr_free(struct smc_link_group *lgr);

static void smc_lgr_free_work(struct work_struct *work)
@@ -246,7 +259,6 @@ static void smc_lgr_free_work(struct work_struct *work)
free_work);
spinlock_t *lgr_lock;
bool conns;
- int i;

smc_lgr_list_head(lgr, &lgr_lock);
spin_lock_bh(lgr_lock);
@@ -271,15 +283,8 @@ static void smc_lgr_free_work(struct work_struct *work)
SMC_LLC_DEL_PROG_INIT_TERM);
if (lgr->is_smcd && !lgr->terminating)
smc_ism_signal_shutdown(lgr);
- if (!lgr->is_smcd) {
- for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) {
- struct smc_link *lnk = &lgr->lnk[i];
-
- if (smc_link_usable(lnk))
- lnk->state = SMC_LNK_INACTIVE;
- }
- wake_up_interruptible_all(&lgr->llc_waiter);
- }
+ if (!lgr->is_smcd)
+ smcr_lgr_link_deactivate_all(lgr);
smc_lgr_free(lgr);
}

@@ -802,6 +807,16 @@ static void smc_lgr_free(struct smc_link_group *lgr)
{
int i;

+ if (!lgr->is_smcd) {
+ mutex_lock(&lgr->llc_conf_mutex);
+ for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) {
+ if (lgr->lnk[i].state != SMC_LNK_UNUSED)
+ smcr_link_clear(&lgr->lnk[i]);
+ }
+ mutex_unlock(&lgr->llc_conf_mutex);
+ smc_llc_lgr_clear(lgr);
+ }
+
smc_lgr_free_bufs(lgr);
if (lgr->is_smcd) {
if (!lgr->terminating) {
@@ -811,11 +826,6 @@ static void smc_lgr_free(struct smc_link_group *lgr)
if (!atomic_dec_return(&lgr->smcd->lgr_cnt))
wake_up(&lgr->smcd->lgrs_deleted);
} else {
- for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) {
- if (lgr->lnk[i].state != SMC_LNK_UNUSED)
- smcr_link_clear(&lgr->lnk[i]);
- }
- smc_llc_lgr_clear(lgr);
if (!atomic_dec_return(&lgr_cnt))
wake_up(&lgrs_deleted);
}
@@ -870,8 +880,6 @@ static void smc_conn_kill(struct smc_connection *conn, bool soft)

static void smc_lgr_cleanup(struct smc_link_group *lgr)
{
- int i;
-
if (lgr->is_smcd) {
smc_ism_signal_shutdown(lgr);
smcd_unregister_all_dmbs(lgr);
@@ -883,13 +891,7 @@ static void smc_lgr_cleanup(struct smc_link_group *lgr)
if (!rsn)
rsn = SMC_LLC_DEL_PROG_INIT_TERM;
smc_llc_send_link_delete_all(lgr, false, rsn);
- for (i = 0; i < SMC_LINKS_PER_LGR_MAX; i++) {
- struct smc_link *lnk = &lgr->lnk[i];
-
- if (smc_link_usable(lnk))
- lnk->state = SMC_LNK_INACTIVE;
- }
- wake_up_interruptible_all(&lgr->llc_waiter);
+ smcr_lgr_link_deactivate_all(lgr);
}
}

@@ -905,8 +907,8 @@ static void __smc_lgr_terminate(struct smc_link_group *lgr, bool soft)

if (lgr->terminating)
return; /* lgr already terminating */
- if (!soft)
- cancel_delayed_work_sync(&lgr->free_work);
+ /* cancel free_work sync, will terminate when lgr->freeing is set */
+ cancel_delayed_work_sync(&lgr->free_work);
lgr->terminating = 1;

/* kill remaining link group connections */
@@ -926,10 +928,7 @@ static void __smc_lgr_terminate(struct smc_link_group *lgr, bool soft)
}
read_unlock_bh(&lgr->conns_lock);
smc_lgr_cleanup(lgr);
- if (soft)
- smc_lgr_schedule_free_work_fast(lgr);
- else
- smc_lgr_free(lgr);
+ smc_lgr_free(lgr);
}

/* unlink link group and schedule termination */
@@ -944,6 +943,7 @@ void smc_lgr_terminate_sched(struct smc_link_group *lgr)
return; /* lgr already terminating */
}
list_del_init(&lgr->list);
+ lgr->freeing = 1;
spin_unlock_bh(lgr_lock);
schedule_work(&lgr->terminate_work);
}
@@ -962,6 +962,7 @@ void smc_smcd_terminate(struct smcd_dev *dev, u64 peer_gid, unsigned short vlan)
if (peer_gid) /* peer triggered termination */
lgr->peer_shutdown = 1;
list_move(&lgr->list, &lgr_free_list);
+ lgr->freeing = 1;
}
}
spin_unlock_bh(&dev->lgr_lock);
--
2.17.1