Re: [PATCH v2 23/53] migration/rdma: Fix QEMUFileHooks method return values

[Juan Quintela]

Markus Armbruster <armbru@redhat.com> wrote:
> The QEMUFileHooks methods don't come with a written contract.  Digging
> through the code calling them, we find:
>
> * save_page():
>
>   Negative values RAM_SAVE_CONTROL_DELAYED and
>   RAM_SAVE_CONTROL_NOT_SUPP are special.  Any other negative value is
>   an unspecified error.
>
>   qemu_rdma_save_page() returns -EIO or rdma->error_state on error.  I
>   believe the latter is always negative.  Nothing stops either of them
>   to clash with the special values, though.  Feels unlikely, but fix
>   it anyway to return only the special values and -1.
>
> * before_ram_iterate(), after_ram_iterate():
>
>   Negative value means error.  qemu_rdma_registration_start() and
>   qemu_rdma_registration_stop() comply as far as I can tell.  Make
>   them comply *obviously*, by returning -1 on error.
>
> * hook_ram_load:
>
>   Negative value means error.  rdma_load_hook() already returns -1 on
>   error.  Leave it alone.
>
> Signed-off-by: Markus Armbruster <armbru@redhat.com>
> Reviewed-by: Li Zhijian <lizhijian@fujitsu.com>

I "remove" QEMUFileHooks on this series:

https://lists.gnu.org/archive/html/qemu-devel/2023-10/msg01037.html

Do you mean waiting for the series to land before adding this one?

As that hooks only get rdma use, I just changed them to be normal
functions, no hooks.

And yes, it was not fun.  I know you have feel the "pleasure" of hacking
this file O:-)

Thanks, Juan.