linux-kernel - [PATCH v6 06/11] virtio: blk: Add freeze, restore handlers to support S4

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Message-Id: <c73aeb0b905ae444631b535f8bf877abee96ec10.1324553223.git.amit.shah@redhat.com>
Date:	Thu, 22 Dec 2011 16:58:30 +0530
From:	Amit Shah <amit.shah@...hat.com>
To:	Virtualization List <virtualization@...ts.linux-foundation.org>
Cc:	Rusty Russell <rusty@...tcorp.com.au>,
	"Michael S. Tsirkin" <mst@...hat.com>,
	linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
	Amit Shah <amit.shah@...hat.com>
Subject: [PATCH v6 06/11] virtio: blk: Add freeze, restore handlers to support S4

Delete the vq and flush any pending requests from the block queue on the
freeze callback to prepare for hibernation.

Re-create the vq in the restore callback to resume normal function.

Signed-off-by: Amit Shah <amit.shah@...hat.com>
---
 drivers/block/virtio_blk.c |   44 ++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 44 insertions(+), 0 deletions(-)

diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index 86c9c5b..e3bd9dc 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -588,6 +588,46 @@ static void __devexit virtblk_remove(struct virtio_device *vdev)
 	ida_simple_remove(&vd_index_ida, index);
 }
 
+#ifdef CONFIG_PM
+static int virtblk_freeze(struct virtio_device *vdev)
+{
+	struct virtio_blk *vblk = vdev->priv;
+
+	/* Ensure we don't receive any more interrupts */
+	vdev->config->reset(vdev);
+
+	/* Prevent config work handler from accessing the device. */
+	mutex_lock(&vblk->config_lock);
+	vblk->config_enable = false;
+	mutex_unlock(&vblk->config_lock);
+
+	flush_work(&vblk->config_work);
+
+	spin_lock_irq(vblk->disk->queue->queue_lock);
+	blk_stop_queue(vblk->disk->queue);
+	spin_unlock_irq(vblk->disk->queue->queue_lock);
+	blk_sync_queue(vblk->disk->queue);
+
+	vdev->config->del_vqs(vdev);
+	return 0;
+}
+
+static int virtblk_restore(struct virtio_device *vdev)
+{
+	struct virtio_blk *vblk = vdev->priv;
+	int ret;
+
+	vblk->config_enable = true;
+	ret = init_vq(vdev->priv);
+	if (!ret) {
+		spin_lock_irq(vblk->disk->queue->queue_lock);
+		blk_start_queue(vblk->disk->queue);
+		spin_unlock_irq(vblk->disk->queue->queue_lock);
+	}
+	return ret;
+}
+#endif
+
 static const struct virtio_device_id id_table[] = {
 	{ VIRTIO_ID_BLOCK, VIRTIO_DEV_ANY_ID },
 	{ 0 },
@@ -613,6 +653,10 @@ static struct virtio_driver __refdata virtio_blk = {
 	.probe			= virtblk_probe,
 	.remove			= __devexit_p(virtblk_remove),
 	.config_changed		= virtblk_config_changed,
+#ifdef CONFIG_PM
+	.freeze			= virtblk_freeze,
+	.restore		= virtblk_restore,
+#endif
 };
 
 static int __init init(void)
-- 
1.7.7.4

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