On Wed, Nov 20, 2013 at 04:22:02PM +0100, Heinz Graalfs wrote:
> Add virtblk_notify() as virtio_driver's notify() callback.
>
> When a transport driver is notified that a device disappeared it
> should invoke this callback to prevent further request queueing.
>
> Subsequent block layer calls of virtio_blk's request function will
> fail, resulting in appropriate I/O errors.
>
> Signed-off-by: Heinz Graalfs <graalfs@xxxxxxxxxxxxxxxxxx>
> ---
> drivers/block/virtio_blk.c | 14 ++++++++++++++
> 1 file changed, 14 insertions(+)
>
> diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
> index 2d43be4..7fc1d62 100644
> --- a/drivers/block/virtio_blk.c
> +++ b/drivers/block/virtio_blk.c
> @@ -901,6 +901,19 @@ static void virtblk_remove(struct virtio_device *vdev)
> ida_simple_remove(&vd_index_ida, index);
> }
>
> +static int virtblk_notify(struct virtio_device *vdev, int event)
> +{
> + struct virtio_blk *vblk = vdev->priv;
> +
> + if (event == VDEV_GONE) {
> + queue_flag_set_unlocked(QUEUE_FLAG_DYING, vblk->disk->queue);
> + queue_flag_set_unlocked(QUEUE_FLAG_NOMERGES, vblk->disk->queue);
> + queue_flag_set_unlocked(QUEUE_FLAG_NOXMERGES,
> + vblk->disk->queue);
> + }
> + return NOTIFY_DONE;
> +}
> +
But what serializes with the block layer?
And is unlocked really safe here?
Don't we need to take the queue lock?
> #ifdef CONFIG_PM
> static int virtblk_freeze(struct virtio_device *vdev)
> {
> @@ -961,6 +974,7 @@ static struct virtio_driver virtio_blk = {
> .probe = virtblk_probe,
> .remove = virtblk_remove,
> .config_changed = virtblk_config_changed,
> + .notify = virtblk_notify,
> #ifdef CONFIG_PM
> .freeze = virtblk_freeze,
> .restore = virtblk_restore,
> --
> 1.8.3.1
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