Re: [Qemu-devel] [PATCH v2 11/17] block-backend: Decrease in_flight only after callback

[Paolo Bonzini]

On 13/09/2018 14:52, Kevin Wolf wrote:
> + if (qemu_get_current_aio_context() == qemu_get_aio_context()) {
> + /* If we are in the main thread, the callback is allowed to unref
> + * the BlockBackend, so we have to hold an additional reference */
> + blk_ref(acb->rwco.blk);
> + }
> acb->common.cb(acb->common.opaque, acb->rwco.ret);
> + blk_dec_in_flight(acb->rwco.blk);
> + if (qemu_get_current_aio_context() == qemu_get_aio_context()) {
> + blk_unref(acb->rwco.blk);
> + }

Is this something that happens only for some specific callers?  That is,
which callers are sure that the callback is invoked from the main thread?

Thanks,

Paolo