Re: [RFC PATCH 0/4] aio: AIO_CONTEXT_ACQUIRE_GUARD() macro experiment

[Philippe Mathieu-Daudé]

On 10/7/21 15:15, Stefan Hajnoczi wrote:
> On Tue, Oct 05, 2021 at 08:58:03PM +0200, Philippe Mathieu-Daudé wrote:
>> Experiment to use glib g_autoptr/autofree features with
>> AIO context.
>> Since this is a RFC, only few examples are provided.
>>
>> TODO: Document the macros in docs/devel/multiple-iothreads.txt
>>
>> Philippe Mathieu-Daudé (4):
>>   block/aio: Add automatically released aio_context variants
>>   hw/scsi/scsi-disk: Use automatic AIO context lock
>>   hw/scsi/scsi-generic: Use automatic AIO context lock
>>   hw/block/virtio-blk: Use automatic AIO context lock
>>
>>  include/block/aio.h    | 24 ++++++++++++++++++++++++
>>  hw/block/virtio-blk.c  | 26 ++++++++++++--------------
>>  hw/scsi/scsi-disk.c    | 13 ++++---------
>>  hw/scsi/scsi-generic.c |  6 +++---
>>  4 files changed, 43 insertions(+), 26 deletions(-)
> 
> This is nice. Two things:
> 
> 1. Emanuele is working on eliminating aio_context_acquire/release(), so
>    a big effort to convert existing code to using guards could be wasted
>    energy and cause conflicts with his patches.

Thanks for the update, I'll wait Emanuele effort to land.

> 2. A few callers anticipate that the AioContext of their BDS may change
>    between acquire/release. Care needs to be taken when converting to
>    preserve the semantics but most instances should be safe to convert.
> 
> Stefan
>