On Wed, Dec 13, 2023 at 10:15 PM Stefan Hajnoczi <stefa...@redhat.com> wrote:
> - /* If a read is in progress, just mark the node as deleted */
> - if (ctx->walking_handlers > 0) {
> - QLIST_INSERT_HEAD_RCU(&ctx->deleted_aio_handlers, node,
> node_deleted);
> - return false;
> + /* If polling was started on the node then end it now */
> + if (ctx->poll_started && node->io_poll_end) {
> + node->io_poll_end(node->opaque);
> +
> + /* Poll one last time in case ->io_poll_end() raced with the event */
> + if (node->io_poll(node->opaque)) {
> + poll_ready = true;
> + }
Do you need this at all? If the caller is removing the handlers, they
should have put themselves in a state where they don't care about the
file descriptor becoming readable.
You still have to be careful because aio_bh_schedule_oneshot() can
trigger remote nested event loops (which can cause deadlocks and, I am
especially afraid, can take some time and invalidate the expectation
that you don't need to drop the BQL). But it does simplify this patch
quite a bit.
Paolo
