Re: [PATCH v4 01/11] block-copy: add missing coroutine_fn annotations

[Kevin Wolf <kwolf@redhat.com>]

Am 16.11.2022 um 13:22 hat Emanuele Giuseppe Esposito geschrieben:
> These functions end up calling bdrv_common_block_status_above(), a
> generated_co_wrapper function.
> In addition, they also happen to be always called in coroutine context,
> meaning all callers are coroutine_fn.
> This means that the g_c_w function will enter the qemu_in_coroutine()
> case and eventually suspend (or in other words call qemu_coroutine_yield()).
> Therefore we need to mark such functions coroutine_fn too.
> 
> Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>

Ideally, we'd convert them to new wrappers bdrv_co_is_allocated() and
bdrv_co_block_status_above() instead of having to argue that they always
take the coroutine path in g_c_w.

> diff --git a/block/block-copy.c b/block/block-copy.c
> index bb947afdda..f33ab1d0b6 100644
> --- a/block/block-copy.c
> +++ b/block/block-copy.c
> @@ -669,8 +671,9 @@ void block_copy_reset(BlockCopyState *s, int64_t offset, int64_t bytes)
>   * @return 0 when the cluster at @offset was unallocated,
>   *         1 otherwise, and -ret on error.
>   */
> -int64_t block_copy_reset_unallocated(BlockCopyState *s,
> -                                     int64_t offset, int64_t *count)
> +int64_t coroutine_fn block_copy_reset_unallocated(BlockCopyState *s,
> +                                                  int64_t offset,
> +                                                  int64_t *count)
>  {
>      int ret;
>      int64_t clusters, bytes;

This one is a public function. Its prototype in block-copy.h should be
updated, too.

Kevin