On 13/03/2015 02:38, Fam Zheng wrote:
> That if the dbs' owner is an iothread, dma should be resumed on the right
> thread. In this case it is the AioContext of the block device.
>
> Signed-off-by: Fam Zheng <f...@redhat.com>
> ---
> dma-helpers.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/dma-helpers.c b/dma-helpers.c
> index 6918572..84f61a7 100644
> --- a/dma-helpers.c
> +++ b/dma-helpers.c
> @@ -95,8 +95,10 @@ static void reschedule_dma(void *opaque)
> static void continue_after_map_failure(void *opaque)
> {
> DMAAIOCB *dbs = (DMAAIOCB *)opaque;
> + AioContext *ctx;
>
> - dbs->bh = qemu_bh_new(reschedule_dma, dbs);
> + ctx = blk_get_aio_context(dbs->blk);
> + dbs->bh = aio_bh_new(ctx, reschedule_dma, dbs);
> qemu_bh_schedule(dbs->bh);
> }
>
>
This looks good. However, I wonder if dma_aio_cancel should also call
cpu_unregister_map_client. In this case, it's much better to just use a
lock for the list (though you can still use atomics for the in-use flag).
Paolo
