netdev - [PATCH net-next 04/10] net/smc: guarantee reset of write

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Date:   Mon, 10 Apr 2017 14:57:59 +0200
From:   Ursula Braun <ubraun@...ux.vnet.ibm.com>
To:     davem@...emloft.net
Cc:     netdev@...r.kernel.org, linux-s390@...r.kernel.org,
        jwi@...ux.vnet.ibm.com, schwidefsky@...ibm.com,
        heiko.carstens@...ibm.com, raspl@...ux.vnet.ibm.com,
        ubraun@...ux.vnet.ibm.com
Subject: [PATCH net-next 04/10] net/smc: guarantee reset of write_blocked for heavy workload

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@...ux.vnet.ibm.com>
Reviewed-by: Thomas Richter <tmricht@...ux.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