Re: [PATCH 4/6] block: introduce IOCTL to report dev properties

Javier González <javier@xxxxxxxxxxx> · Thu, 25 Jun 2020 21:42:48 +0200

On 25.06.2020 15:10, Matias Bjørling wrote:
On 25/06/2020 14.21, Javier González wrote:
From: Javier González <javier.gonz@xxxxxxxxxxx>

With the addition of ZNS, a new set of properties have been added to the
zoned block device. This patch introduces a new IOCTL to expose these
rroperties to user space.

Signed-off-by: Javier González <javier.gonz@xxxxxxxxxxx>
Signed-off-by: SelvaKumar S <selvakuma.s1@xxxxxxxxxxx>
Signed-off-by: Kanchan Joshi <joshi.k@xxxxxxxxxxx>
Signed-off-by: Nitesh Shetty <nj.shetty@xxxxxxxxxxx>
---
 block/blk-zoned.c             | 46 ++++++++++++++++++++++++++
 block/ioctl.c                 |  2 ++
 drivers/nvme/host/core.c      |  2 ++
 drivers/nvme/host/nvme.h      | 11 +++++++
 drivers/nvme/host/zns.c       | 61 +++++++++++++++++++++++++++++++++++
 include/linux/blkdev.h        |  9 ++++++
 include/uapi/linux/blkzoned.h | 13 ++++++++
 7 files changed, 144 insertions(+)

diff --git a/block/blk-zoned.c b/block/blk-zoned.c
index 704fc15813d1..39ec72af9537 100644
--- a/block/blk-zoned.c
+++ b/block/blk-zoned.c
@@ -169,6 +169,17 @@ int blkdev_report_zones(struct block_device *bdev, sector_t sector,
 }
 EXPORT_SYMBOL_GPL(blkdev_report_zones);
+static int blkdev_report_zonedev_prop(struct block_device *bdev,
+				      struct blk_zone_dev *zprop)
+{
+	struct gendisk *disk = bdev->bd_disk;
+
+	if (WARN_ON_ONCE(!bdev->bd_disk->fops->report_zone_p))
+		return -EOPNOTSUPP;
+
+	return disk->fops->report_zone_p(disk, zprop);
+}
+
 static inline bool blkdev_allow_reset_all_zones(struct block_device *bdev,
 						sector_t sector,
 						sector_t nr_sectors)
@@ -430,6 +441,41 @@ int blkdev_zone_mgmt_ioctl(struct block_device *bdev, fmode_t mode,
 				GFP_KERNEL);
 }
+int blkdev_zonedev_prop(struct block_device *bdev, fmode_t mode,
+			unsigned int cmd, unsigned long arg)
+{
+	void __user *argp = (void __user *)arg;
+	struct request_queue *q;
+	struct blk_zone_dev zprop;
+	int ret;
+
+	if (!argp)
+		return -EINVAL;
+
+	q = bdev_get_queue(bdev);
+	if (!q)
+		return -ENXIO;
+
+	if (!blk_queue_is_zoned(q))
+		return -ENOTTY;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EACCES;
+
+	if (!(mode & FMODE_WRITE))
+		return -EBADF;
+
+	ret = blkdev_report_zonedev_prop(bdev, &zprop);
+	if (ret)
+		goto out;
+
+	if (copy_to_user(argp, &zprop, sizeof(struct blk_zone_dev)))
+		return -EFAULT;
+
+out:
+	return ret;
+}
+
 static inline unsigned long *blk_alloc_zone_bitmap(int node,
 						   unsigned int nr_zones)
 {
diff --git a/block/ioctl.c b/block/ioctl.c
index 0ea29754e7dd..f7b4e0f2dd4c 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -517,6 +517,8 @@ static int blkdev_common_ioctl(struct block_device *bdev, fmode_t mode,
 		return blkdev_zone_ops_ioctl(bdev, mode, cmd, arg);
 	case BLKMGMTZONE:
 		return blkdev_zone_mgmt_ioctl(bdev, mode, cmd, arg);
+	case BLKZONEDEVPROP:
+		return blkdev_zonedev_prop(bdev, mode, cmd, arg);
 	case BLKGETZONESZ:
 		return put_uint(argp, bdev_zone_sectors(bdev));
 	case BLKGETNRZONES:
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 5b95c81d2a2d..a32c909a915f 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -2254,6 +2254,7 @@ static const struct block_device_operations nvme_fops = {
 	.getgeo		= nvme_getgeo,
 	.revalidate_disk= nvme_revalidate_disk,
 	.report_zones	= nvme_report_zones,
+	.report_zone_p	= nvme_report_zone_prop,
 	.pr_ops		= &nvme_pr_ops,
 };
@@ -2280,6 +2281,7 @@ const struct block_device_operations nvme_ns_head_ops = {
 	.compat_ioctl	= nvme_compat_ioctl,
 	.getgeo		= nvme_getgeo,
 	.report_zones	= nvme_report_zones,
+	.report_zone_p	= nvme_report_zone_prop,
 	.pr_ops		= &nvme_pr_ops,
 };
 #endif /* CONFIG_NVME_MULTIPATH */
diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index ecf443efdf91..172e0531f37f 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -407,6 +407,14 @@ struct nvme_ns {
 	u8 pi_type;
 #ifdef CONFIG_BLK_DEV_ZONED
 	u64 zsze;
+
+	u32 nr_zones;
+	u32 mar;
+	u32 mor;
+	u32 rrl;
+	u32 frl;
+	u16 zoc;
+	u16 ozcs;
 #endif
 	unsigned long features;
 	unsigned long flags;
@@ -704,11 +712,14 @@ int nvme_update_zone_info(struct gendisk *disk, struct nvme_ns *ns,
 int nvme_report_zones(struct gendisk *disk, sector_t sector,
 		      unsigned int nr_zones, report_zones_cb cb, void *data);
+int nvme_report_zone_prop(struct gendisk *disk, struct blk_zone_dev *zprop);
+
 blk_status_t nvme_setup_zone_mgmt_send(struct nvme_ns *ns, struct request *req,
 				       struct nvme_command *cmnd,
 				       enum nvme_zone_mgmt_action action);
 #else
 #define nvme_report_zones NULL
+#define nvme_report_zone_prop NULL
 static inline blk_status_t nvme_setup_zone_mgmt_send(struct nvme_ns *ns,
 		struct request *req, struct nvme_command *cmnd,
diff --git a/drivers/nvme/host/zns.c b/drivers/nvme/host/zns.c
index 2e6512ac6f01..258d03610cc0 100644
--- a/drivers/nvme/host/zns.c
+++ b/drivers/nvme/host/zns.c
@@ -32,6 +32,28 @@ static int nvme_set_max_append(struct nvme_ctrl *ctrl)
 	return 0;
 }
+static u64 nvme_zns_nr_zones(struct nvme_ns *ns)
+{
+	struct nvme_command c = { };
+	struct nvme_zone_report report;
+	int buflen = sizeof(struct nvme_zone_report);
+	int ret;
+
+	c.zmr.opcode = nvme_cmd_zone_mgmt_recv;
+	c.zmr.nsid = cpu_to_le32(ns->head->ns_id);
+	c.zmr.slba = cpu_to_le64(0);
+	c.zmr.numd = cpu_to_le32(nvme_bytes_to_numd(buflen));
+	c.zmr.zra = NVME_ZRA_ZONE_REPORT;
+	c.zmr.zrasf = NVME_ZRASF_ZONE_REPORT_ALL;
+	c.zmr.pr = 0;
+
+	ret = nvme_submit_sync_cmd(ns->queue, &c, &report, buflen);
+	if (ret)
+		return ret;
+
+	return le64_to_cpu(report.nr_zones);
+}
+
 int nvme_update_zone_info(struct gendisk *disk, struct nvme_ns *ns,
 			  unsigned lbaf)
 {
@@ -87,6 +109,13 @@ int nvme_update_zone_info(struct gendisk *disk, struct nvme_ns *ns,
 		goto free_data;
 	}
+	ns->nr_zones = nvme_zns_nr_zones(ns);
+	ns->mar = le32_to_cpu(id->mar);
+	ns->mor = le32_to_cpu(id->mor);
+	ns->rrl = le32_to_cpu(id->rrl);
+	ns->frl = le32_to_cpu(id->frl);
+	ns->zoc = le16_to_cpu(id->zoc);
+
 	q->limits.zoned = BLK_ZONED_HM;
 	blk_queue_flag_set(QUEUE_FLAG_ZONE_RESETALL, q);
 free_data:
@@ -230,6 +259,38 @@ int nvme_report_zones(struct gendisk *disk, sector_t sector,
 	return ret;
 }
+static int nvme_ns_report_zone_prop(struct nvme_ns *ns, struct blk_zone_dev *zprop)
+{
+	zprop->nr_zones = ns->nr_zones;
+	zprop->zoc = ns->zoc;
+	zprop->ozcs = ns->ozcs;
+	zprop->mar = ns->mar;
+	zprop->mor = ns->mor;
+	zprop->rrl = ns->rrl;
+	zprop->frl = ns->frl;
+
+	return 0;
+}
+
+int nvme_report_zone_prop(struct gendisk *disk, struct blk_zone_dev *zprop)
+{
+	struct nvme_ns_head *head = NULL;
+	struct nvme_ns *ns;
+	int srcu_idx, ret;
+
+	ns = nvme_get_ns_from_disk(disk, &head, &srcu_idx);
+	if (unlikely(!ns))
+		return -EWOULDBLOCK;
+
+	if (ns->head->ids.csi == NVME_CSI_ZNS)
+		ret = nvme_ns_report_zone_prop(ns, zprop);
+	else
+		ret = -EINVAL;
+	nvme_put_ns_from_disk(head, srcu_idx);
+
+	return ret;
+}
+
 blk_status_t nvme_setup_zone_mgmt_send(struct nvme_ns *ns, struct request *req,
 		struct nvme_command *c, enum nvme_zone_mgmt_action action)
 {
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 8308d8a3720b..0c0faa58b7f4 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -372,6 +372,8 @@ extern int blkdev_zone_ops_ioctl(struct block_device *bdev, fmode_t mode,
 				  unsigned int cmd, unsigned long arg);
 extern int blkdev_zone_mgmt_ioctl(struct block_device *bdev, fmode_t mode,
 				  unsigned int cmd, unsigned long arg);
+extern int blkdev_zonedev_prop(struct block_device *bdev, fmode_t mode,
+			unsigned int cmd, unsigned long arg);
 #else /* CONFIG_BLK_DEV_ZONED */
 static inline unsigned int blkdev_nr_zones(struct gendisk *disk)
@@ -400,6 +402,12 @@ static inline int blkdev_zone_mgmt_ioctl(struct block_device *bdev,
 	return -ENOTTY;
 }
+static inline int blkdev_zonedev_prop(struct block_device *bdev, fmode_t mode,
+				      unsigned int cmd, unsigned long arg)
+{
+	return -ENOTTY;
+}
+
 #endif /* CONFIG_BLK_DEV_ZONED */
 struct request_queue {
@@ -1770,6 +1778,7 @@ struct block_device_operations {
 	int (*report_zones)(struct gendisk *, sector_t sector,
 			unsigned int nr_zones, report_zones_cb cb, void *data);
 	char *(*devnode)(struct gendisk *disk, umode_t *mode);
+	int (*report_zone_p)(struct gendisk *disk, struct blk_zone_dev *zprop);
 	struct module *owner;
 	const struct pr_ops *pr_ops;
 };
diff --git a/include/uapi/linux/blkzoned.h b/include/uapi/linux/blkzoned.h
index d0978ee10fc7..0c49a4b2ce5d 100644
--- a/include/uapi/linux/blkzoned.h
+++ b/include/uapi/linux/blkzoned.h
@@ -142,6 +142,18 @@ struct blk_zone_range {
 	__u64		nr_sectors;
 };
+struct blk_zone_dev {
+	__u32	nr_zones;
+	__u32	mar;
+	__u32	mor;
+	__u32	rrl;
+	__u32	frl;
+	__u16	zoc;
+	__u16	ozcs;
+	__u32	rsv31[2];
+	__u64	rsv63[4];
+};
+
 /**
  * enum blk_zone_action - Zone state transitions managed from user-space
  *
@@ -209,5 +221,6 @@ struct blk_zone_mgmt {
 #define BLKCLOSEZONE	_IOW(0x12, 135, struct blk_zone_range)
 #define BLKFINISHZONE	_IOW(0x12, 136, struct blk_zone_range)
 #define BLKMGMTZONE	_IOR(0x12, 137, struct blk_zone_mgmt)
+#define BLKZONEDEVPROP	_IOR(0x12, 138, struct blk_zone_dev)
 #endif /* _UAPI_BLKZONED_H */

Nak. These properties can already be retrieved using the nvme ioctl 
passthru command and support have also been added to nvme-cli.


These properties are intended to be consumed by an application, so
nvme-cli is of not much use. I would also like to avoid sysfs variables.

We can use nvme passthru, but this bypasses the zoned block abstraction.
Why not representing ZNS features in the standard zoned block API? I am
happy to iterate on the actual implementation if you have feedback.

Javier







