On 24/02/2016 22:58, Michael S. Tsirkin wrote:
> Latest virtio spec says the feature bit name is VIRTIO_BLK_F_FLUSH,
> VIRTIO_BLK_F_WCE is the legacy name. virtio blk header says exactly the
> reverse - fix that and update driver code to match.
>
> Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
> ---
>
> Changs from v1:
> comments updated
>
> include/uapi/linux/virtio_blk.h | 6 +++---
> drivers/block/virtio_blk.c | 11 ++++++++---
> 2 files changed, 11 insertions(+), 6 deletions(-)
>
> diff --git a/include/uapi/linux/virtio_blk.h b/include/uapi/linux/virtio_blk.h
> index 19c66fc..9ebe4d9 100644
> --- a/include/uapi/linux/virtio_blk.h
> +++ b/include/uapi/linux/virtio_blk.h
> @@ -43,11 +43,11 @@
> #ifndef VIRTIO_BLK_NO_LEGACY
> #define VIRTIO_BLK_F_BARRIER 0 /* Does host support barriers? */
> #define VIRTIO_BLK_F_SCSI 7 /* Supports scsi command passthru */
> -#define VIRTIO_BLK_F_WCE 9 /* Writeback mode enabled after reset */
> +#define VIRTIO_BLK_F_FLUSH 9 /* Flush command supported */
> #define VIRTIO_BLK_F_CONFIG_WCE 11 /* Writeback mode available in config */
> #ifndef __KERNEL__
> -/* Old (deprecated) name for VIRTIO_BLK_F_WCE. */
> -#define VIRTIO_BLK_F_FLUSH VIRTIO_BLK_F_WCE
> +/* Old (deprecated) name for VIRTIO_BLK_F_FLUSH. */
> +#define VIRTIO_BLK_F_WCE VIRTIO_BLK_F_FLUSH
> #endif
> #endif /* !VIRTIO_BLK_NO_LEGACY */
>
> diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
> index 6ca3549..28cff0d 100644
> --- a/drivers/block/virtio_blk.c
> +++ b/drivers/block/virtio_blk.c
> @@ -477,8 +477,13 @@ static int virtblk_get_cache_mode(struct virtio_device *vdev)
> err = virtio_cread_feature(vdev, VIRTIO_BLK_F_CONFIG_WCE,
> struct virtio_blk_config, wce,
> &writeback);
> +
> + /*
> + * If WCE is not configurable and flush is not available,
> + * assume no writeback cache is in use.
> + */
> if (err)
> - writeback = virtio_has_feature(vdev, VIRTIO_BLK_F_WCE);
> + writeback = virtio_has_feature(vdev, VIRTIO_BLK_F_FLUSH);
>
> return writeback;
> }
> @@ -833,14 +838,14 @@ static const struct virtio_device_id id_table[] = {
> static unsigned int features_legacy[] = {
> VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY,
> VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE, VIRTIO_BLK_F_SCSI,
> - VIRTIO_BLK_F_WCE, VIRTIO_BLK_F_TOPOLOGY, VIRTIO_BLK_F_CONFIG_WCE,
> + VIRTIO_BLK_F_FLUSH, VIRTIO_BLK_F_TOPOLOGY, VIRTIO_BLK_F_CONFIG_WCE,
> VIRTIO_BLK_F_MQ,
> }
> ;
> static unsigned int features[] = {
> VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY,
> VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE,
> - VIRTIO_BLK_F_WCE, VIRTIO_BLK_F_TOPOLOGY, VIRTIO_BLK_F_CONFIG_WCE,
> + VIRTIO_BLK_F_FLUSH, VIRTIO_BLK_F_TOPOLOGY, VIRTIO_BLK_F_CONFIG_WCE,
> VIRTIO_BLK_F_MQ,
> };
>
>
Reviewed-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
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