Re: [Qemu-devel] [PATCH v5 06/12] util/async: add aio interfaces for io_uring

[Maxim Levitsky <mlevitsk@redhat.com>]

On Mon, 2019-06-10 at 19:18 +0530, Aarushi Mehta wrote:
> Signed-off-by: Aarushi Mehta <mehta.aaru20@gmail.com>
> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
> ---
>  util/async.c | 36 ++++++++++++++++++++++++++++++++++++
>  1 file changed, 36 insertions(+)
> 
> diff --git a/util/async.c b/util/async.c
> index c10642a385..2709f0edc3 100644
> --- a/util/async.c
> +++ b/util/async.c
> @@ -277,6 +277,14 @@ aio_ctx_finalize(GSource     *source)
>      }
>  #endif
>  
> +#ifdef CONFIG_LINUX_IO_URING
> +    if (ctx->linux_io_uring) {
> +        luring_detach_aio_context(ctx->linux_io_uring, ctx);
> +        luring_cleanup(ctx->linux_io_uring);
> +        ctx->linux_io_uring = NULL;
> +    }
> +#endif
> +
>      assert(QSLIST_EMPTY(&ctx->scheduled_coroutines));
>      qemu_bh_delete(ctx->co_schedule_bh);
>  
> @@ -341,6 +349,29 @@ LinuxAioState *aio_get_linux_aio(AioContext *ctx)
>  }
>  #endif
>  
> +#ifdef CONFIG_LINUX_IO_URING
> +LuringState *aio_setup_linux_io_uring(AioContext *ctx, Error **errp)
> +{
> +    if (ctx->linux_io_uring) {
> +        return ctx->linux_io_uring;
> +    }
> +
> +    ctx->linux_io_uring = luring_init(errp);
> +    if (!ctx->linux_io_uring) {
> +        return NULL;
> +    }
> +
> +    luring_attach_aio_context(ctx->linux_io_uring, ctx);
> +    return ctx->linux_io_uring;
> +}
> +
> +LuringState *aio_get_linux_io_uring(AioContext *ctx)
> +{
> +    assert(ctx->linux_io_uring);
> +    return ctx->linux_io_uring;
> +}
> +#endif
> +
>  void aio_notify(AioContext *ctx)
>  {

Minor nitpick. Maybe we can memset all the private area of the AioContext to 0, 
and then setup the stuff that is not zero? That would remove most of the code below.
This is an old habit from the kernel code.

(I assume that g_source_new doesn't do this)


>      /* Write e.g. bh->scheduled before reading ctx->notify_me.  Pairs
> @@ -432,6 +463,11 @@ AioContext *aio_context_new(Error **errp)
>  #ifdef CONFIG_LINUX_AIO
>      ctx->linux_aio = NULL;
>  #endif
> +
> +#ifdef CONFIG_LINUX_IO_URING
> +    ctx->linux_io_uring = NULL;
> +#endif
> +
>      ctx->thread_pool = NULL;
>      qemu_rec_mutex_init(&ctx->lock);
>      timerlistgroup_init(&ctx->tlg, aio_timerlist_notify, ctx);


Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>

Best regards,
	Maxim Levitsky