[PATCH net-next 7/8] net/smc: wait for tx completions before link freeing

Karsten Graul
2019-11-14T12:02:46Z

Make sure all pending work requests are completed before freeing
a link.
Dismiss tx pending slots already when terminating a link group to
exploit termination shortcut in tx completion queue handler.

And kill the completion queue tasklets after destroy of the
completion queues, otherwise there is a time window for another
tasklet schedule of an already killed tasklet.

Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
---
net/smc/smc_core.c | 2 ++
net/smc/smc_ib.c | 2 +-
net/smc/smc_wr.c | 27 +++++++++++++++++++++++++--
3 files changed, 28 insertions(+), 3 deletions(-)

diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c
index ee44e8244d0c..0755bd4b587c 100644
--- a/net/smc/smc_core.c
+++ b/net/smc/smc_core.c
@@ -548,6 +548,8 @@ static void smc_conn_kill(struct smc_connection *conn, bool soft)
tasklet_kill(&conn->rx_tsklet);
else
tasklet_unlock_wait(&conn->rx_tsklet);
+ } else {
+ smc_cdc_tx_dismiss_slots(conn);
}
smc_lgr_unregister_conn(conn);
smc_close_active_abort(smc);
diff --git a/net/smc/smc_ib.c b/net/smc/smc_ib.c
index af05daeb0538..c15dcd08dc74 100644
--- a/net/smc/smc_ib.c
+++ b/net/smc/smc_ib.c
@@ -520,9 +520,9 @@ static void smc_ib_cleanup_per_ibdev(struct smc_ib_device *smcibdev)
if (!smcibdev->initialized)
return;
smcibdev->initialized = 0;
- smc_wr_remove_dev(smcibdev);
ib_destroy_cq(smcibdev->roce_cq_recv);
ib_destroy_cq(smcibdev->roce_cq_send);
+ smc_wr_remove_dev(smcibdev);
}

static struct ib_client smc_ib_client;
diff --git a/net/smc/smc_wr.c b/net/smc/smc_wr.c
index 619dd89fbac0..337ee52ad3d3 100644
--- a/net/smc/smc_wr.c
+++ b/net/smc/smc_wr.c
@@ -50,6 +50,26 @@ struct smc_wr_tx_pend { /* control data for a pending send request */

/*------------------------------- completion --------------------------------*/

+/* returns true if at least one tx work request is pending on the given link */
+static inline bool smc_wr_is_tx_pend(struct smc_link *link)
+{
+ if (find_first_bit(link->wr_tx_mask, link->wr_tx_cnt) !=
+ link->wr_tx_cnt) {
+ return true;
+ }
+ return false;
+}
+
+/* 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)
+{
+ if (wait_event_timeout(link->wr_tx_wait, !smc_wr_is_tx_pend(link),
+ SMC_WR_TX_WAIT_PENDING_TIME))
+ return 0;
+ else /* timeout */
+ return -EPIPE;
+}
+
static inline int smc_wr_tx_find_pending_index(struct smc_link *link, u64 wr_id)
{
u32 i;
@@ -229,6 +249,7 @@ int smc_wr_tx_put_slot(struct smc_link *link,
memset(&link->wr_tx_bufs[idx], 0,
sizeof(link->wr_tx_bufs[idx]));
test_and_clear_bit(idx, link->wr_tx_mask);
+ wake_up(&link->wr_tx_wait);
return 1;
}

@@ -512,8 +533,10 @@ void smc_wr_free_link(struct smc_link *lnk)
{
struct ib_device *ibdev;

- memset(lnk->wr_tx_mask, 0,
- BITS_TO_LONGS(SMC_WR_BUF_CNT) * sizeof(*lnk->wr_tx_mask));
+ if (smc_wr_tx_wait_no_pending_sends(lnk))
+ memset(lnk->wr_tx_mask, 0,
+ BITS_TO_LONGS(SMC_WR_BUF_CNT) *
+ sizeof(*lnk->wr_tx_mask));

if (!lnk->smcibdev)
return;
--
2.17.1