Re: [PATCH v3 1/4] io/channel: introduce qio_channel_pread{v,}_all{,_eof}()

["Daniel P. Berrangé" <berrange@redhat.com>]

On Tue, Apr 14, 2026 at 05:45:46AM +0800, Junjie Cao wrote:
> qio_channel_pread() and qio_channel_preadv() perform a single
> positioned read and may return a short result.  Callers that need all
> bytes currently have to open-code a retry loop or simply treat a short
> read as an error.
> 
> Introduce four new helpers following the existing read_all / readv_all
> pattern:
> 
>   qio_channel_preadv_all_eof()  -- retry loop; returns 1 on success,
>                                     0 on clean EOF, -1 on error.
>   qio_channel_preadv_all()      -- wraps _eof; treats early EOF as
>                                     error; returns 0 / -1.
>   qio_channel_pread_all_eof()   -- single-buffer convenience wrapper
>                                     around preadv_all_eof().
>   qio_channel_pread_all()       -- single-buffer convenience wrapper
>                                     around preadv_all().
> 
> These advance the file offset internally after each partial read.
> All four are marked coroutine_mixed_fn, consistent with the existing
> _all helpers.
> 
> Suggested-by: Peter Xu <peterx@redhat.com>
> Signed-off-by: Junjie Cao <junjie.cao@intel.com>
> ---
>  include/io/channel.h | 92 ++++++++++++++++++++++++++++++++++++++++++++
>  io/channel.c         | 91 +++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 183 insertions(+)

Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Acked-by: Daniel P. Berrangé <berrange@redhat.com>


With regards,
Daniel
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