Re: [PATCH] ide: Explicitly poll for BHs on cancel

[Paolo Bonzini]

On 1/5/22 12:13, Hanna Reitz wrote:
> -        assert(s->bus->dma->aiocb == NULL);
> +
> +        /*
> +         * Wait for potentially still-scheduled BHs, like ide_trim_bh_cb()
> +         * (blk_drain() will only poll if there are in-flight requests on the
> +         * BlockBackend, which there may not necessarily be, e.g. when the
> +         * guest has issued a zero-length TRIM request)
> +         */
> +        while (s->bus->dma->aiocb) {
> +            bool progress = aio_poll(qemu_get_aio_context(), true);
> +            assert(progress);
> +        }


I think the right way to do this is to do  blk_inc_in_flight before 
scheduling the bottom half and blk_dec_in_flight in the BH callback. 
See virtio_blk_dma_restart_cb for an example.

Paolo