[PATCH v2] virtio_blk: Add support for lifetime feature

[Enrico Granata <egranata@google.com>]

The VirtIO TC has adopted a new feature in virtio-blk enabling
discovery of lifetime information.

This commit adds support for the VIRTIO_BLK_T_LIFETIME command
to the virtio_blk driver, and adds two new attributes to the
sysfs entry for virtio_blk:
* pre_eol_info
* life_time

which are defined in the same manner as the files of the same name
for the eMMC driver, in line with the VirtIO specification.

Signed-off-by: Enrico Granata <egranata@google.com>
---
Changes in v2:
  - Removed redudnant buffer size checks
  - Renamed variables for consistency
  - Cleaned up endianness

 drivers/block/virtio_blk.c      | 75 +++++++++++++++++++++++++++++++--
 include/uapi/linux/virtio_blk.h | 11 +++++
 2 files changed, 83 insertions(+), 3 deletions(-)

diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index b9fa3ef5b57c..31969f680a9f 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -246,14 +246,15 @@ static blk_status_t virtio_queue_rq(struct blk_mq_hw_ctx *hctx,
 		unmap = !(req->cmd_flags & REQ_NOUNMAP);
 		break;
 	case REQ_OP_DRV_IN:
-		type = VIRTIO_BLK_T_GET_ID;
-		break;
+		break; /* type already set for custom requests */
 	default:
 		WARN_ON_ONCE(1);
 		return BLK_STS_IOERR;
 	}
 
-	vbr->out_hdr.type = cpu_to_virtio32(vblk->vdev, type);
+	if (req_op(req) != REQ_OP_DRV_IN)
+		vbr->out_hdr.type = cpu_to_virtio32(vblk->vdev, type);
+
 	vbr->out_hdr.sector = type ?
 		0 : cpu_to_virtio64(vblk->vdev, blk_rq_pos(req));
 	vbr->out_hdr.ioprio = cpu_to_virtio32(vblk->vdev, req_get_ioprio(req));
@@ -310,11 +311,14 @@ static int virtblk_get_id(struct gendisk *disk, char *id_str)
 	struct virtio_blk *vblk = disk->private_data;
 	struct request_queue *q = vblk->disk->queue;
 	struct request *req;
+	struct virtblk_req *vbr;
 	int err;
 
 	req = blk_get_request(q, REQ_OP_DRV_IN, 0);
 	if (IS_ERR(req))
 		return PTR_ERR(req);
+	vbr = blk_mq_rq_to_pdu(req);
+	vbr->out_hdr.type = cpu_to_virtio32(vblk->vdev, VIRTIO_BLK_T_GET_ID);
 
 	err = blk_rq_map_kern(q, req, id_str, VIRTIO_BLK_ID_BYTES, GFP_KERNEL);
 	if (err)
@@ -327,6 +331,34 @@ static int virtblk_get_id(struct gendisk *disk, char *id_str)
 	return err;
 }
 
+static int virtblk_get_lifetime(struct gendisk *disk, struct virtio_blk_lifetime *lifetime)
+{
+	struct virtio_blk *vblk = disk->private_data;
+	struct request_queue *q = vblk->disk->queue;
+	struct request *req;
+	struct virtblk_req *vbr;
+	int err;
+
+	if (!virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_LIFETIME))
+		return -EOPNOTSUPP;
+
+	req = blk_get_request(q, REQ_OP_DRV_IN, 0);
+	if (IS_ERR(req))
+		return PTR_ERR(req);
+	vbr = blk_mq_rq_to_pdu(req);
+	vbr->out_hdr.type = cpu_to_virtio32(vblk->vdev, VIRTIO_BLK_T_GET_LIFETIME);
+
+	err = blk_rq_map_kern(q, req, lifetime, sizeof(*lifetime), GFP_KERNEL);
+	if (err)
+		goto out;
+
+	blk_execute_rq(vblk->disk, req, false);
+	err = blk_status_to_errno(virtblk_result(blk_mq_rq_to_pdu(req)));
+out:
+	blk_put_request(req);
+	return err;
+}
+
 static void virtblk_get(struct virtio_blk *vblk)
 {
 	refcount_inc(&vblk->refs);
@@ -435,6 +467,40 @@ static ssize_t serial_show(struct device *dev,
 
 static DEVICE_ATTR_RO(serial);
 
+static ssize_t pre_eol_info_show(struct device *dev,
+			   struct device_attribute *attr, char *buf)
+{
+	struct gendisk *disk = dev_to_disk(dev);
+	struct virtio_blk_lifetime lft;
+	int err;
+
+	err = virtblk_get_lifetime(disk, &lft);
+	if (err)
+		return 0;
+
+	return sprintf(buf, "0x%02x\n", le16_to_cpu(lft.pre_eol_info));
+}
+
+static DEVICE_ATTR_RO(pre_eol_info);
+
+static ssize_t life_time_show(struct device *dev,
+			   struct device_attribute *attr, char *buf)
+{
+	struct gendisk *disk = dev_to_disk(dev);
+	struct virtio_blk_lifetime lft;
+	int err;
+
+	err = virtblk_get_lifetime(disk, &lft);
+	if (err)
+		return 0;
+
+	return sprintf(buf, "0x%02x 0x%02x\n",
+			le16_to_cpu(lft.device_life_time_est_typ_a),
+			le16_to_cpu(lft.device_life_time_est_typ_b));
+}
+
+static DEVICE_ATTR_RO(life_time);
+
 /* The queue's logical block size must be set before calling this */
 static void virtblk_update_capacity(struct virtio_blk *vblk, bool resize)
 {
@@ -638,6 +704,8 @@ static DEVICE_ATTR_RW(cache_type);
 
 static struct attribute *virtblk_attrs[] = {
 	&dev_attr_serial.attr,
+	&dev_attr_pre_eol_info.attr,
+	&dev_attr_life_time.attr,
 	&dev_attr_cache_type.attr,
 	NULL,
 };
@@ -984,6 +1052,7 @@ static unsigned int features[] = {
 	VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE,
 	VIRTIO_BLK_F_FLUSH, VIRTIO_BLK_F_TOPOLOGY, VIRTIO_BLK_F_CONFIG_WCE,
 	VIRTIO_BLK_F_MQ, VIRTIO_BLK_F_DISCARD, VIRTIO_BLK_F_WRITE_ZEROES,
+	VIRTIO_BLK_F_LIFETIME,
 };
 
 static struct virtio_driver virtio_blk = {
diff --git a/include/uapi/linux/virtio_blk.h b/include/uapi/linux/virtio_blk.h
index d888f013d9ff..bbd3978b9d08 100644
--- a/include/uapi/linux/virtio_blk.h
+++ b/include/uapi/linux/virtio_blk.h
@@ -40,6 +40,7 @@
 #define VIRTIO_BLK_F_MQ		12	/* support more than one vq */
 #define VIRTIO_BLK_F_DISCARD	13	/* DISCARD is supported */
 #define VIRTIO_BLK_F_WRITE_ZEROES	14	/* WRITE ZEROES is supported */
+#define VIRTIO_BLK_F_LIFETIME	15 /* LIFETIME is supported */
 
 /* Legacy feature bits */
 #ifndef VIRTIO_BLK_NO_LEGACY
@@ -149,6 +150,9 @@ struct virtio_blk_config {
 /* Get device ID command */
 #define VIRTIO_BLK_T_GET_ID    8
 
+/* Get device lifetime command */
+#define VIRTIO_BLK_T_GET_LIFETIME 10
+
 /* Discard command */
 #define VIRTIO_BLK_T_DISCARD	11
 
@@ -196,6 +200,13 @@ struct virtio_scsi_inhdr {
 };
 #endif /* !VIRTIO_BLK_NO_LEGACY */
 
+/* Lifetime information for virtio_blk device */
+struct virtio_blk_lifetime {
+	__le16 pre_eol_info;
+	__le16 device_life_time_est_typ_a;
+	__le16 device_life_time_est_typ_b;
+};
+
 /* And this is the final byte of the write scatter-gather list. */
 #define VIRTIO_BLK_S_OK		0
 #define VIRTIO_BLK_S_IOERR	1
-- 
2.31.1.368.gbe11c130af-goog