Re: [Qemu-devel] [PATCH v3 23/38] blockdev: Pull out blockdev option extraction

[Fam Zheng <famz@redhat.com>]

On Wed, 06/03 21:44, Max Reitz wrote:
> Extract some of the blockdev option extraction code from blockdev_init()
> into its own function. This simplifies blockdev_init() and will allow
> reusing the code in a different function added in a follow-up patch.
> 
> Signed-off-by: Max Reitz <mreitz@redhat.com>
> Reviewed-by: Eric Blake <eblake@redhat.com>
> ---
>  blockdev.c | 201 +++++++++++++++++++++++++++++++++----------------------------
>  1 file changed, 108 insertions(+), 93 deletions(-)
> 
> diff --git a/blockdev.c b/blockdev.c
> index 8c91532..8d672ac 100644
> --- a/blockdev.c
> +++ b/blockdev.c
> @@ -341,24 +341,123 @@ static bool check_throttle_config(ThrottleConfig *cfg, Error **errp)
>  
>  typedef enum { MEDIA_DISK, MEDIA_CDROM } DriveMediaType;
>  
> +static void extract_common_blockdev_options(QemuOpts *opts, int *bdrv_flags,
> +    ThrottleConfig *throttle_cfg, BlockdevDetectZeroesOptions *detect_zeroes,
> +    Error **errp)
> +{
> +    const char *discard, *aio;

This breaks build without CONFIG_LINUX_AIO:

/home/fam/qemu/blockdev.c: In function ‘extract_common_blockdev_options’:
/home/fam/qemu/blockdev.c:348:27: error: unused variable ‘aio’ [-Werror=unused-variable]
     const char *discard, *aio;
                           ^
cc1: all warnings being treated as errors

> +    Error *local_error = NULL;
> +
> +    if (!qemu_opt_get_bool(opts, "read-only", false)) {
> +        *bdrv_flags |= BDRV_O_RDWR;
> +    }
> +    if (qemu_opt_get_bool(opts, "copy-on-read", false)) {
> +        *bdrv_flags |= BDRV_O_COPY_ON_READ;
> +    }
> +
> +    if ((discard = qemu_opt_get(opts, "discard")) != NULL) {
> +        if (bdrv_parse_discard_flags(discard, bdrv_flags) != 0) {
> +            error_setg(errp, "Invalid discard option");
> +            return;
> +        }
> +    }
> +
> +    if (qemu_opt_get_bool(opts, "cache.writeback", true)) {
> +        *bdrv_flags |= BDRV_O_CACHE_WB;
> +    }
> +    if (qemu_opt_get_bool(opts, "cache.direct", false)) {
> +        *bdrv_flags |= BDRV_O_NOCACHE;
> +    }
> +    if (qemu_opt_get_bool(opts, "cache.no-flush", false)) {
> +        *bdrv_flags |= BDRV_O_NO_FLUSH;
> +    }
> +
> +#ifdef CONFIG_LINUX_AIO
> +    if ((aio = qemu_opt_get(opts, "aio")) != NULL) {
> +        if (!strcmp(aio, "native")) {
> +            *bdrv_flags |= BDRV_O_NATIVE_AIO;
> +        } else if (!strcmp(aio, "threads")) {
> +            /* this is the default */
> +        } else {
> +           error_setg(errp, "invalid aio option");
> +           return;
> +        }
> +    }
> +#endif

[snip]

Fam