Re: [Qemu-block] [Qemu-devel] [PATCH 1/3] hw/block: Introduce rotational qdev property

[Philippe Mathieu-Daudé]

On 05/06/2017 09:43 AM, Aurelien Jarno wrote:
> The Linux kernel uses different I/O scheduler depending if the block
> device is a rotational device or not. Also it uses rotational devices
> to add entropy to the random pool.
>
> This patch add a rotational qdev property so that the block device can
> be configured as a rotational device or a non-rotational device. Default
> to true to not change the default behavior.
>
> Signed-off-by: Aurelien Jarno <address@hidden>

Reviewed-by: Philippe Mathieu-Daudé <address@hidden>

> ---
>  blockdev.c               | 4 ++++
>  include/hw/block/block.h | 4 +++-
>  2 files changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/blockdev.c b/blockdev.c
> index 4d8cdedd54..c914420641 100644
> --- a/blockdev.c
> +++ b/blockdev.c
> @@ -4037,6 +4037,10 @@ QemuOptsList qemu_common_drive_opts = {
>              .name = BDRV_OPT_READ_ONLY,
>              .type = QEMU_OPT_BOOL,
>              .help = "open drive file as read-only",
> +        },{
> +            .name = "rotational",
> +            .type = QEMU_OPT_BOOL,
> +            .help = "rotational drive (off, on)",
>          },
>
>          THROTTLE_OPTS,
> diff --git a/include/hw/block/block.h b/include/hw/block/block.h
> index f3f6e8ef02..304a579eca 100644
> --- a/include/hw/block/block.h
> +++ b/include/hw/block/block.h
> @@ -27,6 +27,7 @@ typedef struct BlockConf {
>      uint32_t cyls, heads, secs;
>      OnOffAuto wce;
>      bool share_rw;
> +    bool rotational;
>      BlockdevOnError rerror;
>      BlockdevOnError werror;
>  } BlockConf;
> @@ -56,7 +57,8 @@ static inline unsigned int get_physical_block_exp(BlockConf 
> *conf)
>                         _conf.discard_granularity, -1), \
>      DEFINE_PROP_ON_OFF_AUTO("write-cache", _state, _conf.wce, \
>                              ON_OFF_AUTO_AUTO), \
> -    DEFINE_PROP_BOOL("share-rw", _state, _conf.share_rw, false)
> +    DEFINE_PROP_BOOL("share-rw", _state, _conf.share_rw, false), \
> +    DEFINE_PROP_BOOL("rotational", _state, _conf.rotational, true)
>
>  #define DEFINE_BLOCK_CHS_PROPERTIES(_state, _conf)      \
>      DEFINE_PROP_UINT32("cyls", _state, _conf.cyls, 0),  \