On 2020/11/30 12:29, Chaitanya Kulkarni wrote:

That is really heavy handed... Why not just simply:

return !(get_capacity(ns->bdev->bd_disk) & (bdev_zone_sectors(ns->bdev) - 1));

That does the same: true if capacity is a multiple of the zone size (no runt
zone), false otherwise.

+
+static inline u8 nvmet_zasl(unsigned int zone_append_sects)
+{
+	unsigned int npages = (zone_append_sects << 9) >> NVMET_MPSMIN_SHIFT;
+	u8 zasl = ilog2(npages);
+
+	/*
+	 * Zone Append Size Limit is the value experessed in the units
+	 * of minimum memory page size (i.e. 12) and is reported power of 2.
+	 */
+	return zasl;

Why not just:

	return ilog2((zone_append_sects << 9) >> NVMET_MPSMIN_SHIFT);

And are you sure that there is no possibility that the u8 type overflows here ?

+}
+
+static inline void nvmet_zns_update_zasl(struct nvmet_ns *ns)
+{
+	u8 bio_max_zasl = nvmet_zasl((BIO_MAX_PAGES * PAGE_SIZE) >> 9);
+	struct request_queue *q = ns->bdev->bd_disk->queue;
+	struct nvmet_ns *ins;
+	unsigned long idx;
+	u8 min_zasl;
+
+	/*
+	 * Calculate new ctrl->zasl value when enabling the new ns. This value
+	 * has to be the minimum of the max_zone appned values from available

s/appned/append

+	 * namespaces.
+	 */
+	min_zasl = ns->zasl = nvmet_zasl(queue_max_zone_append_sectors(q));
+
+	xa_for_each(&(ns->subsys->namespaces), idx, ins) {
+		struct request_queue *iq = ins->bdev->bd_disk->queue;
+		unsigned int imax_za_sects = queue_max_zone_append_sectors(iq);
+		u8 izasl = nvmet_zasl(imax_za_sects);
+
+		if (!bdev_is_zoned(ins->bdev))
+			continue;
+
+		min_zasl = min_zasl > izasl ? izasl : min_zasl;
+	}
+
+	ns->subsys->id_ctrl_zns.zasl = min_t(u8, min_zasl, bio_max_zasl);

I do not understand what bio_max_zasl is used for here, as it does not represent
anything related to the zoned namespaces backends.

+}> +
+bool nvmet_bdev_zns_enable(struct nvmet_ns *ns)
+{
+	if (ns->bdev->bd_disk->queue->conv_zones_bitmap) {
+		pr_err("block devices with conventional zones are not supported.");
+		return false;
+	}

It may be better to move this test in nvmet_bdev_validate_zns_zones(), so that
all backend zone configuration checks are together.

+
+	if (!nvmet_bdev_validate_zns_zones(ns))
+		return false;
+
+	/*
+	 * For ZBC and ZAC devices, writes into sequential zones must be aligned
+	 * to the device physical block size. So use this value as the logical
+	 * block size to avoid errors.
+	 */
+	ns->blksize_shift = blksize_bits(bdev_physical_block_size(ns->bdev));
+
+	nvmet_zns_update_zasl(ns);
+
+	return true;
+}
+
+/*
+ * ZNS related Admin and I/O command handlers.
+ */
+void nvmet_execute_identify_cns_cs_ctrl(struct nvmet_req *req)
+{
+	struct nvmet_ctrl *ctrl = req->sq->ctrl;
+	struct nvme_id_ctrl_zns *id;
+	u16 status = 0;
+	u8 mdts;
+
+	id = kzalloc(sizeof(*id), GFP_KERNEL);
+	if (!id) {
+		status = NVME_SC_INTERNAL;
+		goto out;
+	}
+
+	/*
+	 * Even though this function sets Zone Append Size Limit to 0,
+	 * the 0 value here indicates that the maximum data transfer size for
+	 * the Zone Append command is indicated by the ctrl
+	 * Maximum Data Transfer Size (MDTS).
+	 */

I do not understand this comment. It does not really exactly match what the code
below is doing.

+
+	mdts = ctrl->ops->get_mdts ? ctrl->ops->get_mdts(ctrl) : 0;
+
+	id->zasl = min_t(u8, mdts, req->sq->ctrl->subsys->id_ctrl_zns.zasl);
+
+	status = nvmet_copy_to_sgl(req, 0, id, sizeof(*id));
+
+	kfree(id);
+out:
+	nvmet_req_complete(req, status);
+}
+
+void nvmet_execute_identify_cns_cs_ns(struct nvmet_req *req)
+{
+	struct nvme_id_ns_zns *id_zns;
+	u16 status = 0;
+	u64 zsze;
+
+	if (le32_to_cpu(req->cmd->identify.nsid) == NVME_NSID_ALL) {
+		req->error_loc = offsetof(struct nvme_identify, nsid);
+		status = NVME_SC_INVALID_NS | NVME_SC_DNR;
+		goto out;
+	}
+
+	id_zns = kzalloc(sizeof(*id_zns), GFP_KERNEL);
+	if (!id_zns) {
+		status = NVME_SC_INTERNAL;
+		goto out;
+	}
+
+	req->ns = nvmet_find_namespace(req->sq->ctrl, req->cmd->identify.nsid);
+	if (!req->ns) {
+		status = NVME_SC_INTERNAL;
+		goto done;
+	}
+
+	if (!bdev_is_zoned(nvmet_bdev(req))) {
+		req->error_loc = offsetof(struct nvme_identify, nsid);
+		status = NVME_SC_INVALID_NS | NVME_SC_DNR;
+		goto done;
+	}
+
+	nvmet_ns_revalidate(req->ns);
+	zsze = (bdev_zone_sectors(nvmet_bdev(req)) << 9) >>
+					req->ns->blksize_shift;
+	id_zns->lbafe[0].zsze = cpu_to_le64(zsze);
+	id_zns->mor = cpu_to_le32(bdev_max_open_zones(nvmet_bdev(req)));
+	id_zns->mar = cpu_to_le32(bdev_max_active_zones(nvmet_bdev(req)));
+
+done:
+	status = nvmet_copy_to_sgl(req, 0, id_zns, sizeof(*id_zns));
+	kfree(id_zns);
+out:
+	nvmet_req_complete(req, status);
+}
+
+struct nvmet_report_zone_data {
+	struct nvmet_ns *ns;
+	struct nvme_zone_report *rz;
+};
+
+static int nvmet_bdev_report_zone_cb(struct blk_zone *z, unsigned int idx,
+				     void *data)
+{
+	struct nvmet_report_zone_data *report_zone_data = data;
+	struct nvme_zone_descriptor *entries = report_zone_data->rz->entries;
+	struct nvmet_ns *ns = report_zone_data->ns;
+
+	entries[idx].zcap = cpu_to_le64(nvmet_sect_to_lba(ns, z->capacity));
+	entries[idx].zslba = cpu_to_le64(nvmet_sect_to_lba(ns, z->start));
+	entries[idx].wp = cpu_to_le64(nvmet_sect_to_lba(ns, z->wp));
+	entries[idx].za = z->reset ? 1 << 2 : 0;
+	entries[idx].zt = z->type;
+	entries[idx].zs = z->cond << 4;
+
+	return 0;
+}
+
+void nvmet_bdev_execute_zone_mgmt_recv(struct nvmet_req *req)
+{
+	u32 bufsize = (le32_to_cpu(req->cmd->zmr.numd) + 1) << 2;

size_t ?

+	struct nvmet_report_zone_data data = { .ns = req->ns };
+	struct nvme_zone_mgmt_recv_cmd *zmr = &req->cmd->zmr;
+	sector_t sect = nvmet_lba_to_sect(req->ns, le64_to_cpu(zmr->slba));
+	unsigned int nr_zones = bufsize / nvmet_zones_to_desc_size(1);

I think this is wrong since nvmet_zones_to_desc_size includes sizeof(struct
nvme_zone_report). I think what you want here is:

nr_zones = (bufsize - sizeof(struct nvme_zone_report)) /
	sizeof(struct nvme_zone_descriptor);

And then you can get rid of nvmet_zones_to_desc_size();

+	int reported_zones;
+	u16 status;
+
+	status = nvmet_bdev_zns_checks(req);
+	if (status)
+		goto out;
+
+	data.rz = __vmalloc(bufsize, GFP_KERNEL | __GFP_NORETRY);
+	if (!data.rz) {
+		status = NVME_SC_INTERNAL;
+		goto out;
+	}
+
+	reported_zones = blkdev_report_zones(nvmet_bdev(req), sect, nr_zones,
+					     nvmet_bdev_report_zone_cb,
+					     &data);
+	if (reported_zones < 0) {
+		status = NVME_SC_INTERNAL;
+		goto out_free_report_zones;
+	}
+
+	data.rz->nr_zones = cpu_to_le64(reported_zones);
+
+	status = nvmet_copy_to_sgl(req, 0, data.rz, bufsize);
+
+out_free_report_zones:
+	kvfree(data.rz);
+out:
+	nvmet_req_complete(req, status);
+}
+
+void nvmet_bdev_execute_zone_mgmt_send(struct nvmet_req *req)
+{
+	sector_t nr_sect = bdev_zone_sectors(nvmet_bdev(req));
+	struct nvme_zone_mgmt_send_cmd *c = &req->cmd->zms;
+	enum req_opf op = REQ_OP_LAST;
+	u16 status = NVME_SC_SUCCESS;
+	sector_t sect;
+	int ret;
+
+	sect = nvmet_lba_to_sect(req->ns, le64_to_cpu(req->cmd->zms.slba));
+
+	switch (c->zsa) {
+	case NVME_ZONE_OPEN:
+		op = REQ_OP_ZONE_OPEN;
+		break;
+	case NVME_ZONE_CLOSE:
+		op = REQ_OP_ZONE_CLOSE;
+		break;
+	case NVME_ZONE_FINISH:
+		op = REQ_OP_ZONE_FINISH;
+		break;
+	case NVME_ZONE_RESET:
+		if (c->select_all)
+			nr_sect = get_capacity(nvmet_bdev(req)->bd_disk);
+		op = REQ_OP_ZONE_RESET;
+		break;
+	default:
+		status = NVME_SC_INVALID_FIELD;
+		goto out;
+	}
+
+	ret = blkdev_zone_mgmt(nvmet_bdev(req), op, sect, nr_sect, GFP_KERNEL);
+	if (ret)
+		status = NVME_SC_INTERNAL;
+
+out:
+	nvmet_req_complete(req, status);
+}
+
+void nvmet_bdev_execute_zone_append(struct nvmet_req *req)
+{
+	unsigned long bv_cnt = req->sg_cnt;
+	int op = REQ_OP_ZONE_APPEND | REQ_SYNC | REQ_IDLE;
+	u64 slba = le64_to_cpu(req->cmd->rw.slba);
+	sector_t sect = nvmet_lba_to_sect(req->ns, slba);
+	u16 status = NVME_SC_SUCCESS;
+	size_t mapped_data_len = 0;
+	int sg_cnt = req->sg_cnt;
+	struct scatterlist *sg;
+	struct iov_iter from;
+	struct bio_vec *bvec;
+	size_t mapped_cnt;
+	struct bio *bio;
+	int ret;
+
+	if (!nvmet_check_transfer_len(req, nvmet_rw_data_len(req)))
+		return;
+
+	/*
+	 * When setting the ctrl->zasl we consider the BIO_MAX_PAGES so that we
+	 * don't have to split the bio, i.e. we shouldn't get
+	 * sg_cnt > BIO_MAX_PAGES since zasl on the host will limit the I/Os
+	 * with the size that considers the BIO_MAX_PAGES.
+	 */

What ? Unclear... You advertize max zone append as ctrl->zasl = min(all ns max
zone append sectors). What does BIO_MAX_PAGES has to do with anything ?

+	if (!req->sg_cnt)
+		goto out;
+
+	if (WARN_ON(req->sg_cnt > BIO_MAX_PAGES)) {
+		status = NVME_SC_INTERNAL | NVME_SC_DNR;
+		goto out;
+	}
+
+	bvec = kmalloc_array(bv_cnt, sizeof(*bvec), GFP_KERNEL);
+	if (!bvec) {
+		status = NVME_SC_INTERNAL | NVME_SC_DNR;
+		goto out;
+	}
+
+	for_each_sg(req->sg, sg, req->sg_cnt, mapped_cnt) {
+		nvmet_file_init_bvec(bvec, sg);
+		mapped_data_len += bvec[mapped_cnt].bv_len;
+		sg_cnt--;
+		if (mapped_cnt == bv_cnt)
+			break;
+	}
+
+	if (WARN_ON(sg_cnt)) {
+		status = NVME_SC_INTERNAL | NVME_SC_DNR;
+		goto out;
+	}
+
+	iov_iter_bvec(&from, WRITE, bvec, mapped_cnt, mapped_data_len);
+
+	bio = bio_alloc(GFP_KERNEL, bv_cnt);
+	bio_set_dev(bio, nvmet_bdev(req));
+	bio->bi_iter.bi_sector = sect;
+	bio->bi_opf = op;

The op variable is used only here. It is not necessary.

+
+	ret =  __bio_iov_append_get_pages(bio, &from);

I still do not see why bio_iov_iter_get_pages() does not work here. Would you
care to explain please ?

+	if (unlikely(ret)) {
+		status = NVME_SC_INTERNAL | NVME_SC_DNR;
+		bio_io_error(bio);
+		goto bvec_free;
+	}
+
+	ret = submit_bio_wait(bio);
+	status = ret < 0 ? NVME_SC_INTERNAL : status;
+	bio_put(bio);
+
+	sect += (mapped_data_len >> 9);
+	req->cqe->result.u64 = le64_to_cpu(nvmet_sect_to_lba(req->ns, sect));
+
+bvec_free:
+	kfree(bvec);
+
+out:
+	nvmet_req_complete(req, status);
+}
+
+#else  /* CONFIG_BLK_DEV_ZONED */
+void nvmet_execute_identify_cns_cs_ctrl(struct nvmet_req *req)
+{
+}
+void nvmet_execute_identify_cns_cs_ns(struct nvmet_req *req)
+{
+}
+u16 nvmet_process_zns_cis(struct nvmet_req *req, off_t *off)
+{
+	return 0;
+}
+bool nvmet_bdev_zns_config(struct nvmet_ns *ns)
+{
+	return false;
+}
+void nvmet_bdev_execute_zone_mgmt_recv(struct nvmet_req *req)
+{
+}
+void nvmet_bdev_execute_zone_mgmt_send(struct nvmet_req *req)
+{
+}
+void nvmet_bdev_execute_zone_append(struct nvmet_req *req)
+{
+}
+void nvmet_zns_add_cmd_effects(struct nvme_effects_log *log)
+{
+}
+#endif /* CONFIG_BLK_DEV_ZONED */

-- 
Damien Le Moal
Western Digital Research