Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934206AbbDUQ16 (ORCPT ); Tue, 21 Apr 2015 12:27:58 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:57116 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755623AbbDUPcq (ORCPT ); Tue, 21 Apr 2015 11:32:46 -0400 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: "Michael S. Tsirkin" , Rusty Russell , Luis Henriques Subject: [PATCH 3.16.y-ckt 015/144] virtio_console: avoid config access from irq Date: Tue, 21 Apr 2015 16:30:00 +0100 Message-Id: <1429630329-21748-16-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1429630329-21748-1-git-send-email-luis.henriques@canonical.com> References: <1429630329-21748-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.16 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2863 Lines: 85 3.16.7-ckt10 -stable review patch. If anyone has any objections, please let me know. ------------------ From: "Michael S. Tsirkin" commit eeb8a7e8bb123e84daeef84f5a2eab99ad2839a2 upstream. when multiport is off, virtio console invokes config access from irq context, config access is blocking on s390. Fix this up by scheduling work from config irq - similar to what we do for multiport configs. Signed-off-by: Michael S. Tsirkin Reviewed-by: Amit Shah Signed-off-by: Rusty Russell Signed-off-by: Luis Henriques --- drivers/char/virtio_console.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c index 5f6dce6c20fb..73294b270b93 100644 --- a/drivers/char/virtio_console.c +++ b/drivers/char/virtio_console.c @@ -142,6 +142,7 @@ struct ports_device { * notification */ struct work_struct control_work; + struct work_struct config_work; struct list_head ports; @@ -1832,10 +1833,21 @@ static void config_intr(struct virtio_device *vdev) portdev = vdev->priv; + if (!use_multiport(portdev)) + schedule_work(&portdev->config_work); +} + +static void config_work_handler(struct work_struct *work) +{ + struct ports_device *portdev; + + portdev = container_of(work, struct ports_device, control_work); if (!use_multiport(portdev)) { + struct virtio_device *vdev; struct port *port; u16 rows, cols; + vdev = portdev->vdev; virtio_cread(vdev, struct virtio_console_config, cols, &cols); virtio_cread(vdev, struct virtio_console_config, rows, &rows); @@ -2024,6 +2036,7 @@ static int virtcons_probe(struct virtio_device *vdev) spin_lock_init(&portdev->ports_lock); INIT_LIST_HEAD(&portdev->ports); + INIT_WORK(&portdev->config_work, &config_work_handler); INIT_WORK(&portdev->control_work, &control_work_handler); if (multiport) { @@ -2098,6 +2111,8 @@ static void virtcons_remove(struct virtio_device *vdev) /* Finish up work that's lined up */ if (use_multiport(portdev)) cancel_work_sync(&portdev->control_work); + else + cancel_work_sync(&portdev->config_work); list_for_each_entry_safe(port, port2, &portdev->ports, list) unplug_port(port); @@ -2149,6 +2164,7 @@ static int virtcons_freeze(struct virtio_device *vdev) virtqueue_disable_cb(portdev->c_ivq); cancel_work_sync(&portdev->control_work); + cancel_work_sync(&portdev->config_work); /* * Once more: if control_work_handler() was running, it would * enable the cb as the last step. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/