NVMe: Add scsi unmap to SG_IO

Translates a scsi unmap request from SG_IO ioctl to NVMe
data-set-management deallocate.
Signed-off-by: Keith Busch <keith.busch@intel.com>
Acked-by: Vishal Verma <vishal.l.verma@linux.intel.com>
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>

drivers/block/nvme-scsi.c

@@ -100,6 +100,7 @@ static int sg_version_num = 30534;	/* 2 digits for each component */
 #define FORMAT_UNIT_PROT_INT_OFFSET			3
 #define FORMAT_UNIT_PROT_FIELD_USAGE_OFFSET		0
 #define FORMAT_UNIT_PROT_FIELD_USAGE_MASK		0x07
+#define UNMAP_CDB_PARAM_LIST_LENGTH_OFFSET		7
 
 /* Misc. defines */
 #define NIBBLE_SHIFT					4
@@ -2862,6 +2863,80 @@ static int nvme_trans_write_buffer(struct nvme_ns *ns, struct sg_io_hdr *hdr,
 	return res;
 }
 
+struct scsi_unmap_blk_desc {
+	__be64	slba;
+	__be32	nlb;
+	u32	resv;
+};
+
+struct scsi_unmap_parm_list {
+	__be16	unmap_data_len;
+	__be16	unmap_blk_desc_data_len;
+	u32	resv;
+	struct scsi_unmap_blk_desc desc[0];
+};
+
+static int nvme_trans_unmap(struct nvme_ns *ns, struct sg_io_hdr *hdr,
+							u8 *cmd)
+{
+	struct nvme_dev *dev = ns->dev;
+	struct scsi_unmap_parm_list *plist;
+	struct nvme_dsm_range *range;
+	struct nvme_queue *nvmeq;
+	struct nvme_command c;
+	int i, nvme_sc, res = -ENOMEM;
+	u16 ndesc, list_len;
+	dma_addr_t dma_addr;
+
+	list_len = GET_U16_FROM_CDB(cmd, UNMAP_CDB_PARAM_LIST_LENGTH_OFFSET);
+	if (!list_len)
+		return -EINVAL;
+
+	plist = kmalloc(list_len, GFP_KERNEL);
+	if (!plist)
+		return -ENOMEM;
+
+	res = nvme_trans_copy_from_user(hdr, plist, list_len);
+	if (res != SNTI_TRANSLATION_SUCCESS)
+		goto out;
+
+	ndesc = be16_to_cpu(plist->unmap_blk_desc_data_len) >> 4;
+	if (!ndesc || ndesc > 256) {
+		res = -EINVAL;
+		goto out;
+	}
+
+	range = dma_alloc_coherent(&dev->pci_dev->dev, ndesc * sizeof(*range),
+							&dma_addr, GFP_KERNEL);
+	if (!range)
+		goto out;
+
+	for (i = 0; i < ndesc; i++) {
+		range[i].nlb = cpu_to_le32(be32_to_cpu(plist->desc[i].nlb));
+		range[i].slba = cpu_to_le64(be64_to_cpu(plist->desc[i].slba));
+		range[i].cattr = 0;
+	}
+
+	memset(&c, 0, sizeof(c));
+	c.dsm.opcode = nvme_cmd_dsm;
+	c.dsm.nsid = cpu_to_le32(ns->ns_id);
+	c.dsm.prp1 = cpu_to_le64(dma_addr);
+	c.dsm.nr = cpu_to_le32(ndesc - 1);
+	c.dsm.attributes = cpu_to_le32(NVME_DSMGMT_AD);
+
+	nvmeq = get_nvmeq(dev);
+	put_nvmeq(nvmeq);
+
+	nvme_sc = nvme_submit_sync_cmd(nvmeq, &c, NULL, NVME_IO_TIMEOUT);
+	res = nvme_trans_status_code(hdr, nvme_sc);
+
+	dma_free_coherent(&dev->pci_dev->dev, ndesc * sizeof(*range),
+							range, dma_addr);
+ out:
+	kfree(plist);
+	return res;
+}
+
 static int nvme_scsi_translate(struct nvme_ns *ns, struct sg_io_hdr *hdr)
 {
 	u8 cmd[BLK_MAX_CDB];
@@ -2936,6 +3011,9 @@ static int nvme_scsi_translate(struct nvme_ns *ns, struct sg_io_hdr *hdr)
 	case WRITE_BUFFER:
 		retcode = nvme_trans_write_buffer(ns, hdr, cmd);
 		break;
+	case UNMAP:
+		retcode = nvme_trans_unmap(ns, hdr, cmd);
+		break;
 	default:
  out:
 		retcode = nvme_trans_completion(hdr, SAM_STAT_CHECK_CONDITION,