[PATCH net-next 04/10] net/smc: guarantee reset of write_blocked for heavy workload

Ursula Braun
2017-04-10T12:57:59Z

If peer indicates write_blocked, the cursor state of the received data
should be send to the peer immediately (in smc_tx_consumer_update()).
Afterwards the write_blocked indicator is cleared.

If there is no free slot for another write request, sending is postponed
to worker smc_tx_work, and the write_blocked indicator is not cleared.
Therefore another clearing check is needed in smc_tx_work().

Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Reviewed-by: Thomas Richter <tmricht@linux.vnet.ibm.com>
---
net/smc/smc_tx.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/net/smc/smc_tx.c b/net/smc/smc_tx.c
index 69a0013..21ec183 100644
--- a/net/smc/smc_tx.c
+++ b/net/smc/smc_tx.c
@@ -431,9 +431,13 @@ static void smc_tx_work(struct work_struct *work)
struct smc_connection,
tx_work);
struct smc_sock *smc = container_of(conn, struct smc_sock, conn);
+ int rc;

lock_sock(&smc->sk);
- smc_tx_sndbuf_nonempty(conn);
+ rc = smc_tx_sndbuf_nonempty(conn);
+ if (!rc && conn->local_rx_ctrl.prod_flags.write_blocked &&
+ !atomic_read(&conn->bytes_to_rcv))
+ conn->local_rx_ctrl.prod_flags.write_blocked = 0;
release_sock(&smc->sk);
}

--
2.10.2