s390/qeth: invoke softirqs after napi_schedule()

[ Upstream commit 4d19db777a2f32c9b76f6fd517ed8960576cb43e ]

Calling napi_schedule() from process context does not ensure that the
NET_RX softirq is run in a timely fashion. So trigger it manually.

This is no big issue with current code. A call to ndo_open() is usually
followed by a ndo_set_rx_mode() call, and for qeth this contains a
spin_unlock_bh(). Except for OSN, where qeth_l2_set_rx_mode() bails out
early.
Nevertheless it's best to not depend on this behaviour, and just fix
the issue at its source like all other drivers do. For instance see
commit 83a0c6e58901 ("i40e: Invoke softirqs after napi_reschedule").

Fixes: a1c3ed4c9ca0 ("qeth: NAPI support for l2 and l3 discipline")
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/s390/net/qeth_l2_main.c b/drivers/s390/net/qeth_l2_main.c
index 22045e7d78ac390652a06a767bb5fc22c2743f03..97211f7f0cf029e610741d1e0064662b6e61291b 100644 (file)
--- a/drivers/s390/net/qeth_l2_main.c
+++ b/drivers/s390/net/qeth_l2_main.c
@@ -996,7 +996,10 @@ static int __qeth_l2_open(struct net_device *dev)
 
        if (qdio_stop_irq(card->data.ccwdev, 0) >= 0) {
                napi_enable(&card->napi);
+               local_bh_disable();
                napi_schedule(&card->napi);
+               /* kick-start the NAPI softirq: */
+               local_bh_enable();
        } else
                rc = -EIO;
        return rc;

diff --git a/drivers/s390/net/qeth_l3_main.c b/drivers/s390/net/qeth_l3_main.c
index 2cc9bc1ef1e383875de3899b1cb054484db5267e..0d71d2e6419af84574b2acdb480804f6e567c327 100644 (file)
--- a/drivers/s390/net/qeth_l3_main.c
+++ b/drivers/s390/net/qeth_l3_main.c
@@ -3031,7 +3031,10 @@ static int __qeth_l3_open(struct net_device *dev)
 
        if (qdio_stop_irq(card->data.ccwdev, 0) >= 0) {
                napi_enable(&card->napi);
+               local_bh_disable();
                napi_schedule(&card->napi);
+               /* kick-start the NAPI softirq: */
+               local_bh_enable();
        } else
                rc = -EIO;
        return rc;