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Re: [PATCH v3 2/2] hw/block/nvme: add the dataset management command
From: |
Keith Busch |
Subject: |
Re: [PATCH v3 2/2] hw/block/nvme: add the dataset management command |
Date: |
Wed, 21 Oct 2020 17:59:41 -0700 |
On Thu, Oct 22, 2020 at 12:17:36AM +0200, Klaus Jensen wrote:
> +static void nvme_aio_discard_cb(void *opaque, int ret)
> +{
> + NvmeRequest *req = opaque;
> + int *discards = req->opaque;
> +
> + trace_pci_nvme_aio_discard_cb(nvme_cid(req));
> +
> + if (ret) {
> + req->status = NVME_INTERNAL_DEV_ERROR;
> + trace_pci_nvme_err_aio(nvme_cid(req), strerror(ret),
> + req->status);
> + }
> +
> + if (discards && --(*discards) > 0) {
> + return;
> + }
> +
> + g_free(req->opaque);
> + req->opaque = NULL;
> +
> + nvme_enqueue_req_completion(nvme_cq(req), req);
> +}
> +
> +static uint16_t nvme_dsm(NvmeCtrl *n, NvmeRequest *req)
> +{
> + NvmeNamespace *ns = req->ns;
> + NvmeDsmCmd *dsm = (NvmeDsmCmd *) &req->cmd;
> + NvmeDsmRange *range = NULL;
> + int *discards = NULL;
> +
> + uint32_t attr = le32_to_cpu(dsm->attributes);
> + uint32_t nr = (le32_to_cpu(dsm->nr) & 0xff) + 1;
> +
> + uint16_t status = NVME_SUCCESS;
> +
> + trace_pci_nvme_dsm(nvme_cid(req), nvme_nsid(ns), nr, attr);
> +
> + if (attr & NVME_DSMGMT_AD) {
> + int64_t offset;
> + size_t len;
> +
> + range = g_new(NvmeDsmRange, nr);
> +
> + status = nvme_dma(n, (uint8_t *)range, nr * sizeof(NvmeDsmRange),
> + DMA_DIRECTION_TO_DEVICE, req);
> + if (status) {
> + goto out;
> + }
> +
> + discards = g_new0(int, 1);
> + req->opaque = discards;
I think you need to initialize discards to 1 so that this function is
holding a reference on it while the asynchronous part is running.
Otherwise, the callback may see 'discards' at 0 and free it while we're
trying to discard the next range.
> +
> + for (int i = 0; i < nr; i++) {
> + uint64_t slba = le64_to_cpu(range[i].slba);
> + uint32_t nlb = le32_to_cpu(range[i].nlb);
> +
> + if (nvme_check_bounds(n, ns, slba, nlb)) {
> + trace_pci_nvme_err_invalid_lba_range(slba, nlb,
> + ns->id_ns.nsze);
> + continue;
> + }
> +
> + trace_pci_nvme_dsm_deallocate(nvme_cid(req), nvme_nsid(ns), slba,
> + nlb);
> +
> + offset = nvme_l2b(ns, slba);
> + len = nvme_l2b(ns, nlb);
> +
> + while (len) {
> + size_t bytes = MIN(BDRV_REQUEST_MAX_BYTES, len);
> +
> + blk_aio_pdiscard(ns->blkconf.blk, offset, bytes,
> + nvme_aio_discard_cb, req);
> +
> + (*discards)++;
The increment ought to be before the aio call so that the _cb can't see
the value before it's accounted for.
> +
> + offset += bytes;
> + len -= bytes;
> + }
> + }
> +
> + if (*discards) {
> + status = NVME_NO_COMPLETE;
> + } else {
> + g_free(discards);
> + req->opaque = NULL;
> + }
> + }
> +
> +out:
> + g_free(range);
> +
> + return status;
> +}
> +
> static uint16_t nvme_flush(NvmeCtrl *n, NvmeRequest *req)
> {
> block_acct_start(blk_get_stats(req->ns->blkconf.blk), &req->acct, 0,
> @@ -1088,6 +1183,8 @@ static uint16_t nvme_io_cmd(NvmeCtrl *n, NvmeRequest
> *req)
> case NVME_CMD_WRITE:
> case NVME_CMD_READ:
> return nvme_rw(n, req);
> + case NVME_CMD_DSM:
> + return nvme_dsm(n, req);
> default:
> trace_pci_nvme_err_invalid_opc(req->cmd.opcode);
> return NVME_INVALID_OPCODE | NVME_DNR;
> @@ -2810,7 +2907,7 @@ static void nvme_init_ctrl(NvmeCtrl *n, PCIDevice
> *pci_dev)
> id->cqes = (0x4 << 4) | 0x4;
> id->nn = cpu_to_le32(n->num_namespaces);
> id->oncs = cpu_to_le16(NVME_ONCS_WRITE_ZEROES | NVME_ONCS_TIMESTAMP |
> - NVME_ONCS_FEATURES);
> + NVME_ONCS_FEATURES | NVME_ONCS_DSM);
I think we should set ID_NS.NDPG and NDPA since there really is a
preferred granularity and alignment.
>
> id->vwc = 0x1;
> id->sgls = cpu_to_le32(NVME_CTRL_SGLS_SUPPORT_NO_ALIGN |
> --
> 2.28.0
>