On Mon, Jan 30, 2017 at 07:13:51PM +0100, Christoph Hellwig wrote:
> Support deallocating of LBAs using the DSM command by wiring it up to
> the qemu discard implementation. The other DSM operations which are
> purely advisory are ignored for now.
>
> Based on an implementation by Keith Busch in the qemu-nvme.git repository,
> but rewritten to use the qemu AIO infrastructure properly to not block
> the main thread on discard requests, and cleaned up a little bit.
>
> Signed-off-by: Christoph Hellwig <h...@lst.de>
Thanks for doing this. I've one comment below, but I don't think it should
block this unless you see a good way to fix it.
Reviewed-by: Keith Busch <keith.bu...@intel.com>
> + for (i = 0; i < nr; i++) {
> + uint64_t slba = le64_to_cpu(range[i].slba);
> + uint32_t nlb = le32_to_cpu(range[i].nlb);
> +
> + if (slba + nlb > le64_to_cpu(ns->id_ns.nsze)) {
> + return NVME_LBA_RANGE | NVME_DNR;
> + }
> +
> + req->aio_inflight++;
> + req->aiocb = blk_aio_pdiscard(n->conf.blk, slba << data_shift,
> + nlb << data_shift, nvme_discard_cb,
> req);
Overwriting the request's aiocb here for a multiple ranges is potentially
a problem if we have to cancel the request later. That scenario is
extremely unlikely, though, so I don't think it's worth addressing.
