Re: [Qemu-devel] [PATCH 2/3] qcow2: Always execute preallocate() in a coroutine

[Eric Blake]

On 10/09/2017 04:55 PM, Max Reitz wrote:
> Some qcow2 functions (at least perform_cow()) expect s->lock to be
> taken.  Therefore, if we want to make use of them, we should execute
> preallocate() (as "preallocate_co") in a coroutine so that we can use
> the qemu_co_mutex_* functions.
> 
> Signed-off-by: Max Reitz <address@hidden>
> ---
>  block/qcow2.c | 41 ++++++++++++++++++++++++++++++++++-------
>  1 file changed, 34 insertions(+), 7 deletions(-)
> 

> +++ b/block/qcow2.c
> @@ -2460,6 +2460,14 @@ static int qcow2_set_up_encryption(BlockDriverState 
> *bs, const char *encryptfmt,
>  }
>  
>  
> +typedef struct PreallocCo {
> +    BlockDriverState *bs;
> +    uint64_t offset;
> +    uint64_t new_length;
> +
> +    int ret;
> +} PreallocCo;

Because you create a typedef here...


> +static void coroutine_fn preallocate_co(void *opaque)
>  {
> +    struct PreallocCo *params = opaque;

you could drop 'struct' here, the way you already dropped it...

> +static int preallocate(BlockDriverState *bs,
> +                       uint64_t offset, uint64_t new_length)
> +{
> +    PreallocCo params = {
> +        .bs         = bs,
> +        .offset     = offset,
> +        .new_length = new_length,
> +        .ret        = -EINPROGRESS,
> +    };

...here.  But that doesn't change semantics, so either way,

Reviewed-by: Eric Blake <address@hidden>

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org

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