From: Julian Wiedmann Date: Mon, 17 Sep 2018 15:36:06 +0000 (+0200) Subject: s390/qeth: invoke softirqs after napi_schedule() X-Git-Tag: Ubuntu-5.4-5.4.0-11.14~4189^2~352^2~3 X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=4d19db777a2f32c9b76f6fd517ed8960576cb43e;p=mirror_ubuntu-focal-kernel.git s390/qeth: invoke softirqs after napi_schedule() 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 Signed-off-by: David S. Miller --- diff --git a/drivers/s390/net/qeth_l2_main.c b/drivers/s390/net/qeth_l2_main.c index 33b65471a68a..6285af373bdf 100644 --- a/drivers/s390/net/qeth_l2_main.c +++ b/drivers/s390/net/qeth_l2_main.c @@ -755,7 +755,10 @@ 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 5d7e2921ab36..8930d2a9fcad 100644 --- a/drivers/s390/net/qeth_l3_main.c +++ b/drivers/s390/net/qeth_l3_main.c @@ -2293,7 +2293,10 @@ 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;