Re: [PATCH v3 1/1] io: invert the return semantics of qio_channel_flush

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

On Fri, Mar 20, 2026 at 08:39:41AM +0000, Tejus GK wrote:
> With the kernel's zerocopy notification mechanism, the caller can
> determine whether
>  * All syscalls successfully used zero copy
>  * At least one syscall failed to use zero copy
> 
> But, as of now QEMU's IO channel flush function semantics are like
>  * 1 => all syscalls failed to use zero copy
>  * 0 => at least one syscall successfully used zero copy
> 
> This is not aligned with what the kernel reports, and ends up reporting
> false negatives for cases like when there's just a single successful
> zerocopy amongst a collection of deferred zero-copies during a flush.
> 
> Fix this by inverting the return semantics of the IO flush function.
> 
> Suggested-by: Peter Xu <peterx@redhat.com>
> Suggested-by: Daniel P. Berrangé <berrange@redhat.com>
> Signed-off-by: Tejus GK <tejus.gk@nutanix.com>
> ---
>  include/io/channel-socket.h |  6 +-----
>  include/io/channel.h        |  4 ++--
>  io/channel-socket.c         | 16 ++++++++--------
>  3 files changed, 11 insertions(+), 15 deletions(-)

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


With regards,
Daniel
-- 
|: https://berrange.com       ~~        https://hachyderm.io/@berrange :|
|: https://libvirt.org          ~~          https://entangle-photo.org :|
|: https://pixelfed.art/berrange   ~~    https://fstop138.berrange.com :|