[PATCH v4 0/5] Initial support for multi-actuator HDDs

[PATCH v4 0/5] Initial support for multi-actuator HDDs

[Damien Le Moal]

Single LUN multi-actuator hard-disks are cappable to seek and execute
multiple commands in parallel. This capability is exposed to the host
using the Concurrent Positioning Ranges VPD page (SCSI) and Log (ATA).
Each positioning range describes the contiguous set of LBAs that an
actuator serves.

This series adds support the scsi disk driver to retreive this
information and advertize it to user space through sysfs. libata is also
modified to handle ATA drives.

The first patch adds the block layer plumbing to expose concurrent
sector ranges of the device through sysfs as a sub-directory of the
device sysfs queue directory. Patch 2 and 3 add support to sd and
libata. Finally patch 4 documents the sysfs queue attributed changes.
Patch 5 fixes a typo in the document file (strictly speaking, not
related to this series).

This series does not attempt in any way to optimize accesses to
multi-actuator devices (e.g. block IO scheduler or filesystems). This
initial support only exposes the actuators information to user space
through sysfs.

Changes from v3:
* Modified patch 1:
  - Prefix functions that take a struct gendisk as argument with
    "disk_". Modified patch 2 accordingly.
  - Added a functional release operation for struct blk_cranges kobj to
    ensure that this structure is freed only after all references to it
    are released, including kobject_del() execution for all crange sysfs
    entries.
* Added patch 5 to separate the typo fix from the crange documentation
  addition.
* Added reviewed-by tags

Changes from v2:
* Update patch 1 to fix a compilation warning for a potential NULL
  pointer dereference of the cr argument of blk_queue_set_cranges().
  Warning reported by the kernel test robot <lkp@intel.com>).

Changes from v1:
* Moved libata-scsi hunk from patch 1 to patch 3 where it belongs
* Fixed unintialized variable in patch 2
  Reported-by: kernel test robot <lkp@intel.com>
  Reported-by: Dan Carpenter <dan.carpenter@oracle.com
* Changed patch 3 adding struct ata_cpr_log to contain both the number
  of concurrent ranges and the array of concurrent ranges.
* Added a note in the documentation (patch 4) about the unit used for
  the concurrent ranges attributes.

Damien Le Moal (4):
  block: Add concurrent positioning ranges support
  scsi: sd: add concurrent positioning ranges support
  libata: support concurrent positioning ranges log
  doc: document sysfs queue/cranges attributes

Damien Le Moal (5):
  block: Add concurrent positioning ranges support
  scsi: sd: add concurrent positioning ranges support
  libata: support concurrent positioning ranges log
  doc: document sysfs queue/cranges attributes
  doc: Fix typo in request queue sysfs documentation

 Documentation/block/queue-sysfs.rst |  30 ++-
 block/Makefile                      |   2 +-
 block/blk-cranges.c                 | 310 ++++++++++++++++++++++++++++
 block/blk-sysfs.c                   |  26 ++-
 block/blk.h                         |   4 +
 drivers/ata/libata-core.c           |  52 +++++
 drivers/ata/libata-scsi.c           |  48 ++++-
 drivers/scsi/sd.c                   |  81 ++++++++
 drivers/scsi/sd.h                   |   1 +
 include/linux/ata.h                 |   1 +
 include/linux/blkdev.h              |  29 +++
 include/linux/libata.h              |  15 ++
 12 files changed, 580 insertions(+), 19 deletions(-)
 create mode 100644 block/blk-cranges.c

-- 
2.31.1

[PATCH v4 1/5] block: Add concurrent positioning ranges support

[Damien Le Moal]

The Concurrent Positioning Ranges VPD page (for SCSI) and Log (for ATA)
contain parameters describing the number of sets of contiguous LBAs that
can be served independently by a single LUN multi-actuator disk. This
patch provides the blk_queue_set_cranges() function allowing a device
driver to signal to the block layer that a disk has multiple actuators,
each one serving a contiguous range of sectors. To describe the set
of sector ranges representing the different actuators of a device, the
data type struct blk_cranges is introduced.

For a device with multiple actuators, a struct blk_cranges is attached
to the device request queue by the disk_set_cranges() function. The
function disk_alloc_cranges() is provided for drivers to allocate this
structure.

The blk_cranges structure contains kobjects (struct kobject) to register
with sysfs the set of sector ranges defined by a device. On initial
device scan, this registration is done from blk_register_queue() using
the block layer internal function disk_register_cranges(). If a driver
calls disk_set_cranges() for a registered queue, e.g. when a device
is revalidated, disk_set_cranges() will execute disk_register_cranges()
to update the queue sysfs attribute files.

The sysfs file structure created starts from the cranges sub-directory
and contains the start sector and number of sectors served by an
actuator, with the information for each actuator grouped in one
directory per actuator. E.g. for a dual actuator drive, we have:

$ tree /sys/block/sdk/queue/cranges/
/sys/block/sdk/queue/cranges/
|-- 0
|   |-- nr_sectors
|   `-- sector
`-- 1
    |-- nr_sectors
    `-- sector

For a regular single actuator device, the cranges directory does not
exist.

Device revalidation may lead to changes to this structure and to the
attribute values. When manipulated, the queue sysfs_lock and
sysfs_dir_lock are held for atomicity, similarly to how the blk-mq and
elevator sysfs queue sub-directories are protected.

The code related to the management of cranges is added in the new
file block/blk-cranges.c.

Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
---
 block/Makefile         |   2 +-
 block/blk-cranges.c    | 310 +++++++++++++++++++++++++++++++++++++++++
 block/blk-sysfs.c      |  26 ++--
 block/blk.h            |   4 +
 include/linux/blkdev.h |  29 ++++
 5 files changed, 362 insertions(+), 9 deletions(-)
 create mode 100644 block/blk-cranges.c

diff --git a/block/Makefile b/block/Makefile
index 0d951adce796..7b8a2b969537 100644
--- a/block/Makefile
+++ b/block/Makefile
@@ -9,7 +9,7 @@ obj-$(CONFIG_BLOCK) := bio.o elevator.o blk-core.o blk-sysfs.o \
 			blk-lib.o blk-mq.o blk-mq-tag.o blk-stat.o \
 			blk-mq-sysfs.o blk-mq-cpumap.o blk-mq-sched.o ioctl.o \
 			genhd.o ioprio.o badblocks.o partitions/ blk-rq-qos.o \
-			disk-events.o
+			disk-events.o blk-cranges.o
 
 obj-$(CONFIG_BOUNCE)		+= bounce.o
 obj-$(CONFIG_BLK_SCSI_REQUEST)	+= scsi_ioctl.o
diff --git a/block/blk-cranges.c b/block/blk-cranges.c
new file mode 100644
index 000000000000..edd03d0dbe35
--- /dev/null
+++ b/block/blk-cranges.c
@@ -0,0 +1,310 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  Block device concurrent positioning ranges.
+ *
+ *  Copyright (C) 2021 Western Digital Corporation or its Affiliates.
+ */
+#include <linux/kernel.h>
+#include <linux/blkdev.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+
+#include "blk.h"
+
+static ssize_t blk_crange_sector_show(struct blk_crange *cr, char *page)
+{
+	return sprintf(page, "%llu\n", cr->sector);
+}
+
+static ssize_t blk_crange_nr_sectors_show(struct blk_crange *cr, char *page)
+{
+	return sprintf(page, "%llu\n", cr->nr_sectors);
+}
+
+struct blk_crange_sysfs_entry {
+	struct attribute attr;
+	ssize_t (*show)(struct blk_crange *cr, char *page);
+};
+
+static struct blk_crange_sysfs_entry blk_crange_sector_entry = {
+	.attr = { .name = "sector", .mode = 0444 },
+	.show = blk_crange_sector_show,
+};
+
+static struct blk_crange_sysfs_entry blk_crange_nr_sectors_entry = {
+	.attr = { .name = "nr_sectors", .mode = 0444 },
+	.show = blk_crange_nr_sectors_show,
+};
+
+static struct attribute *blk_crange_attrs[] = {
+	&blk_crange_sector_entry.attr,
+	&blk_crange_nr_sectors_entry.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(blk_crange);
+
+static ssize_t blk_crange_sysfs_show(struct kobject *kobj,
+				     struct attribute *attr, char *page)
+{
+	struct blk_crange_sysfs_entry *entry =
+		container_of(attr, struct blk_crange_sysfs_entry, attr);
+	struct blk_crange *cr = container_of(kobj, struct blk_crange, kobj);
+	ssize_t ret;
+
+	mutex_lock(&cr->queue->sysfs_lock);
+	ret = entry->show(cr, page);
+	mutex_unlock(&cr->queue->sysfs_lock);
+
+	return ret;
+}
+
+static const struct sysfs_ops blk_crange_sysfs_ops = {
+	.show	= blk_crange_sysfs_show,
+};
+
+/*
+ * crange entries are not freed individually, but alltogether with the
+ * struct blk_cranges and its array of range entries. since kobject_add()
+ * takes a reference on the parent struct blk_cranges kobj, the array of
+ * crange entries cannot be freed until kobject_del() is called for all entries.
+ * So we do not need to do anything here, but still need this nop release
+ * operation to avoid complaints from the kobject code.
+ */
+static void blk_crange_sysfs_nop_release(struct kobject *kobj)
+{
+}
+
+static struct kobj_type blk_crange_ktype = {
+	.sysfs_ops	= &blk_crange_sysfs_ops,
+	.default_groups	= blk_crange_groups,
+	.release	= blk_crange_sysfs_nop_release,
+};
+
+/*
+ * This will be executed only after all range entries are removed
+ * with kobject_del(), at which point, it is safe to free everything,
+ * including the array of range entries.
+ */
+static void blk_cranges_sysfs_release(struct kobject *kobj)
+{
+	struct blk_cranges *cranges =
+		container_of(kobj, struct blk_cranges, kobj);
+
+	kfree(cranges);
+}
+
+static struct kobj_type blk_cranges_ktype = {
+	.release	= blk_cranges_sysfs_release,
+};
+
+/**
+ * blk_register_cranges - register with sysfs a set of concurrent ranges
+ * @disk:		Target disk
+ * @new_cranges:	New set of concurrent ranges
+ *
+ * Register with sysfs a set of concurrent ranges for @disk. If @new_cranges
+ * is not NULL, this set of concurrent ranges is registered and the
+ * old set specified by q->cranges is unregistered. Otherwise, q->cranges
+ * is registered if it is not already.
+ */
+int disk_register_cranges(struct gendisk *disk, struct blk_cranges *new_cranges)
+{
+	struct request_queue *q = disk->queue;
+	struct blk_cranges *cranges;
+	int i, ret;
+
+	lockdep_assert_held(&q->sysfs_dir_lock);
+	lockdep_assert_held(&q->sysfs_lock);
+
+	/* If a new range set is specified, unregister the old one */
+	if (new_cranges) {
+		if (q->cranges)
+			disk_unregister_cranges(disk);
+		q->cranges = new_cranges;
+	}
+
+	cranges = q->cranges;
+	if (!cranges)
+		return 0;
+
+	/*
+	 * At this point, cranges is the new set of sector ranges that needs
+	 * to be registered with sysfs.
+	 */
+	WARN_ON(cranges->sysfs_registered);
+	ret = kobject_init_and_add(&cranges->kobj, &blk_cranges_ktype,
+				   &q->kobj, "%s", "cranges");
+	if (ret) {
+		q->cranges = NULL;
+		kfree(cranges);
+		return ret;
+	}
+
+	for (i = 0; i < cranges->nr_ranges; i++) {
+		cranges->ranges[i].queue = q;
+		ret = kobject_init_and_add(&cranges->ranges[i].kobj,
+					   &blk_crange_ktype, &cranges->kobj,
+					   "%d", i);
+		if (ret) {
+			while (--i >= 0)
+				kobject_del(&cranges->ranges[i].kobj);
+			kobject_del(&cranges->kobj);
+			kobject_put(&cranges->kobj);
+			return ret;
+		}
+	}
+
+	cranges->sysfs_registered = true;
+
+	return 0;
+}
+
+void disk_unregister_cranges(struct gendisk *disk)
+{
+	struct request_queue *q = disk->queue;
+	struct blk_cranges *cranges = q->cranges;
+	int i;
+
+	lockdep_assert_held(&q->sysfs_dir_lock);
+	lockdep_assert_held(&q->sysfs_lock);
+
+	if (!cranges)
+		return;
+
+	if (cranges->sysfs_registered) {
+		for (i = 0; i < cranges->nr_ranges; i++)
+			kobject_del(&cranges->ranges[i].kobj);
+		kobject_del(&cranges->kobj);
+		kobject_put(&cranges->kobj);
+	} else {
+		kfree(cranges);
+	}
+
+	q->cranges = NULL;
+}
+
+static bool disk_check_ranges(struct gendisk *disk, struct blk_cranges *cr)
+{
+	sector_t capacity = get_capacity(disk);
+	sector_t min_sector = (sector_t)-1;
+	sector_t max_sector = 0;
+	int i;
+
+	/*
+	 * Sector ranges may overlap but should overall contain all sectors
+	 * within the disk capacity.
+	 */
+	for (i = 0; i < cr->nr_ranges; i++) {
+		min_sector = min(min_sector, cr->ranges[i].sector);
+		max_sector = max(max_sector, cr->ranges[i].sector +
+					     cr->ranges[i].nr_sectors);
+	}
+
+	if (min_sector != 0 || max_sector < capacity) {
+		pr_warn("Invalid concurrent ranges: missing sectors\n");
+		return false;
+	}
+
+	if (max_sector > capacity) {
+		pr_warn("Invalid concurrent ranges: beyond capacity\n");
+		return false;
+	}
+
+	return true;
+}
+
+static bool disk_cranges_changed(struct gendisk *disk, struct blk_cranges *new)
+{
+	struct blk_cranges *old = disk->queue->cranges;
+	int i;
+
+	if (!old)
+		return true;
+
+	if (old->nr_ranges != new->nr_ranges)
+		return true;
+
+	for (i = 0; i < old->nr_ranges; i++) {
+		if (new->ranges[i].sector != old->ranges[i].sector ||
+		    new->ranges[i].nr_sectors != old->ranges[i].nr_sectors)
+			return true;
+	}
+
+	return false;
+}
+
+/**
+ * disk_alloc_cranges - Allocate a concurrent positioning range structure
+ * @disk:	target disk
+ * @nr_ranges:	Number of concurrent ranges
+ *
+ * Allocate a struct blk_cranges structure with @nr_ranges range descriptors.
+ */
+struct blk_cranges *disk_alloc_cranges(struct gendisk *disk, int nr_ranges)
+{
+	struct blk_cranges *cr;
+
+	cr = kzalloc_node(struct_size(cr, ranges, nr_ranges), GFP_KERNEL,
+			  disk->queue->node);
+	if (cr)
+		cr->nr_ranges = nr_ranges;
+	return cr;
+}
+EXPORT_SYMBOL_GPL(disk_alloc_cranges);
+
+/**
+ * disk_set_cranges - Set a disk concurrent positioning ranges
+ * @disk:	target disk
+ * @cr:		concurrent ranges structure
+ *
+ * Set the concurrant positioning ranges information of the request queue
+ * of @disk to @cr. If @cr is NULL and the concurrent ranges structure
+ * already set, if any, is cleared. If there are no differences between
+ * @cr and the concurrent ranges structure already set, @cr is freed.
+ */
+void disk_set_cranges(struct gendisk *disk, struct blk_cranges *cr)
+{
+	struct request_queue *q = disk->queue;
+
+	if (WARN_ON_ONCE(cr && !cr->nr_ranges)) {
+		kfree(cr);
+		cr = NULL;
+	}
+
+	mutex_lock(&q->sysfs_dir_lock);
+	mutex_lock(&q->sysfs_lock);
+
+	if (cr) {
+		if (!disk_check_ranges(disk, cr)) {
+			kfree(cr);
+			cr = NULL;
+			goto reg;
+		}
+
+		if (!disk_cranges_changed(disk, cr)) {
+			kfree(cr);
+			goto unlock;
+		}
+	}
+
+	/*
+	 * This may be called for a registered queue. E.g. during a device
+	 * revalidation. If that is the case, we need to unregister the old
+	 * set of concurrent ranges and register the new set. If the queue
+	 * is not registered, the device request queue registration will
+	 * register the ranges, so only swap in the new set and free the
+	 * old one.
+	 */
+reg:
+	if (blk_queue_registered(q)) {
+		disk_register_cranges(disk, cr);
+	} else {
+		swap(q->cranges, cr);
+		kfree(cr);
+	}
+
+unlock:
+	mutex_unlock(&q->sysfs_lock);
+	mutex_unlock(&q->sysfs_dir_lock);
+}
+EXPORT_SYMBOL_GPL(disk_set_cranges);
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index 1832587dce3a..be8e02356a26 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -897,16 +897,15 @@ int blk_register_queue(struct gendisk *disk)
 	}
 
 	mutex_lock(&q->sysfs_lock);
+
+	ret = disk_register_cranges(disk, NULL);
+	if (ret)
+		goto put_dev;
+
 	if (q->elevator) {
 		ret = elv_register_queue(q, false);
-		if (ret) {
-			mutex_unlock(&q->sysfs_lock);
-			mutex_unlock(&q->sysfs_dir_lock);
-			kobject_del(&q->kobj);
-			blk_trace_remove_sysfs(dev);
-			kobject_put(&dev->kobj);
-			return ret;
-		}
+		if (ret)
+			goto put_dev;
 	}
 
 	blk_queue_flag_set(QUEUE_FLAG_REGISTERED, q);
@@ -937,6 +936,16 @@ int blk_register_queue(struct gendisk *disk)
 		percpu_ref_switch_to_percpu(&q->q_usage_counter);
 	}
 
+	return ret;
+
+put_dev:
+	disk_unregister_cranges(disk);
+	mutex_unlock(&q->sysfs_lock);
+	mutex_unlock(&q->sysfs_dir_lock);
+	kobject_del(&q->kobj);
+	blk_trace_remove_sysfs(dev);
+	kobject_put(&dev->kobj);
+
 	return ret;
 }
 EXPORT_SYMBOL_GPL(blk_register_queue);
@@ -983,6 +992,7 @@ void blk_unregister_queue(struct gendisk *disk)
 	mutex_lock(&q->sysfs_lock);
 	if (q->elevator)
 		elv_unregister_queue(q);
+	disk_unregister_cranges(disk);
 	mutex_unlock(&q->sysfs_lock);
 	mutex_unlock(&q->sysfs_dir_lock);
 
diff --git a/block/blk.h b/block/blk.h
index 56f33fbcde59..149cd5ef8eeb 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -367,4 +367,8 @@ extern struct device_attribute dev_attr_events;
 extern struct device_attribute dev_attr_events_async;
 extern struct device_attribute dev_attr_events_poll_msecs;
 
+int disk_register_cranges(struct gendisk *disk,
+			  struct blk_cranges *new_cranges);
+void disk_unregister_cranges(struct gendisk *disk);
+
 #endif /* BLK_INTERNAL_H */
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 07eef02325b4..476fc5104a95 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -377,6 +377,29 @@ static inline int blkdev_zone_mgmt_ioctl(struct block_device *bdev,
 
 #endif /* CONFIG_BLK_DEV_ZONED */
 
+/*
+ * Concurrent sector ranges: struct blk_crange describes range of
+ * contiguous sectors that can be served by independent resources on the
+ * device. The set of ranges defined in struct blk_cranges must overall
+ * include all sectors within the device capacity.
+ * For a device with multiple ranges, e.g. a single LUN multi-actuator HDD,
+ * requests targeting sectors in different ranges can be executed in parallel.
+ * A request can straddle a range boundary.
+ */
+struct blk_crange {
+	struct kobject		kobj;
+	struct request_queue	*queue;
+	sector_t		sector;
+	sector_t		nr_sectors;
+};
+
+struct blk_cranges {
+	struct kobject		kobj;
+	bool			sysfs_registered;
+	unsigned int		nr_ranges;
+	struct blk_crange	ranges[];
+};
+
 struct request_queue {
 	struct request		*last_merge;
 	struct elevator_queue	*elevator;
@@ -567,6 +590,9 @@ struct request_queue {
 
 #define BLK_MAX_WRITE_HINTS	5
 	u64			write_hints[BLK_MAX_WRITE_HINTS];
+
+	/* Concurrent sector ranges */
+	struct blk_cranges	*cranges;
 };
 
 /* Keep blk_queue_flag_name[] in sync with the definitions below */
@@ -1161,6 +1187,9 @@ extern void blk_queue_required_elevator_features(struct request_queue *q,
 extern bool blk_queue_can_use_dma_map_merging(struct request_queue *q,
 					      struct device *dev);
 
+struct blk_cranges *disk_alloc_cranges(struct gendisk *disk, int nr_ranges);
+void disk_set_cranges(struct gendisk *disk, struct blk_cranges *cr);
+
 /*
  * Number of physical segments as sent to the device.
  *
-- 
2.31.1

[PATCH v4 2/5] scsi: sd: add concurrent positioning ranges support

[Damien Le Moal]

Add the sd_read_cpr() function to the sd scsi disk driver to discover
if a device has multiple concurrent positioning ranges (i.e. multiple
actuators on an HDD). This new function is called from
sd_revalidate_disk() and uses the block layer functions
blk_alloc_cranges() and blk_queue_set_cranges() to set a device
cranges according to the information retrieved from log page B9h,
if the device supports it.

The format of the Concurrent Positioning Ranges VPD page B9h is defined
in section 6.6.6 of SBC-5.

Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 drivers/scsi/sd.c | 81 +++++++++++++++++++++++++++++++++++++++++++++++
 drivers/scsi/sd.h |  1 +
 2 files changed, 82 insertions(+)

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index b8d55af763f9..5480d75f4883 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -3125,6 +3125,86 @@ static void sd_read_security(struct scsi_disk *sdkp, unsigned char *buffer)
 		sdkp->security = 1;
 }
 
+static inline sector_t sd64_to_sectors(struct scsi_disk *sdkp, u8 *buf)
+{
+	return logical_to_sectors(sdkp->device, get_unaligned_be64(buf));
+}
+
+/**
+ * sd_read_cpr - Query concurrent positioning ranges
+ * @sdkp:	disk to query
+ */
+static void sd_read_cpr(struct scsi_disk *sdkp)
+{
+	unsigned char *buffer = NULL;
+	struct blk_cranges *cr = NULL;
+	unsigned int nr_cpr = 0;
+	int i, vpd_len, buf_len = SD_BUF_SIZE;
+	u8 *desc;
+
+	/*
+	 * We need to have the capacity set first for the block layer to be
+	 * able to check the ranges.
+	 */
+	if (sdkp->first_scan)
+		return;
+
+	if (!sdkp->capacity)
+		goto out;
+
+	/*
+	 * Concurrent Positioning Ranges VPD: there can be at most 256 ranges,
+	 * leading to a maximum page size of 64 + 256*32 bytes.
+	 */
+	buf_len = 64 + 256*32;
+	buffer = kmalloc(buf_len, GFP_KERNEL);
+	if (!buffer || scsi_get_vpd_page(sdkp->device, 0xb9, buffer, buf_len))
+		goto out;
+
+	/* We must have at least a 64B header and one 32B range descriptor */
+	vpd_len = get_unaligned_be16(&buffer[2]) + 3;
+	if (vpd_len > buf_len || vpd_len < 64 + 32 || (vpd_len & 31)) {
+		sd_printk(KERN_ERR, sdkp,
+			  "Invalid Concurrent Positioning Ranges VPD page\n");
+		goto out;
+	}
+
+	nr_cpr = (vpd_len - 64) / 32;
+	if (nr_cpr == 1) {
+		nr_cpr = 0;
+		goto out;
+	}
+
+	cr = disk_alloc_cranges(sdkp->disk, nr_cpr);
+	if (!cr) {
+		nr_cpr = 0;
+		goto out;
+	}
+
+	desc = &buffer[64];
+	for (i = 0; i < nr_cpr; i++, desc += 32) {
+		if (desc[0] != i) {
+			sd_printk(KERN_ERR, sdkp,
+				"Invalid Concurrent Positioning Range number\n");
+			nr_cpr = 0;
+			break;
+		}
+
+		cr->ranges[i].sector = sd64_to_sectors(sdkp, desc + 8);
+		cr->ranges[i].nr_sectors = sd64_to_sectors(sdkp, desc + 16);
+	}
+
+out:
+	disk_set_cranges(sdkp->disk, cr);
+	if (nr_cpr && sdkp->nr_actuators != nr_cpr) {
+		sd_printk(KERN_NOTICE, sdkp,
+			  "%u concurrent positioning ranges\n", nr_cpr);
+		sdkp->nr_actuators = nr_cpr;
+	}
+
+	kfree(buffer);
+}
+
 /*
  * Determine the device's preferred I/O size for reads and writes
  * unless the reported value is unreasonably small, large, not a
@@ -3240,6 +3320,7 @@ static int sd_revalidate_disk(struct gendisk *disk)
 		sd_read_app_tag_own(sdkp, buffer);
 		sd_read_write_same(sdkp, buffer);
 		sd_read_security(sdkp, buffer);
+		sd_read_cpr(sdkp);
 	}
 
 	/*
diff --git a/drivers/scsi/sd.h b/drivers/scsi/sd.h
index b59136c4125b..2e5932bde43d 100644
--- a/drivers/scsi/sd.h
+++ b/drivers/scsi/sd.h
@@ -106,6 +106,7 @@ struct scsi_disk {
 	u8		protection_type;/* Data Integrity Field */
 	u8		provisioning_mode;
 	u8		zeroing_mode;
+	u8		nr_actuators;		/* Number of actuators */
 	unsigned	ATO : 1;	/* state of disk ATO bit */
 	unsigned	cache_override : 1; /* temp override of WCE,RCD */
 	unsigned	WCE : 1;	/* state of disk WCE bit */
-- 
2.31.1

[PATCH v4 3/5] libata: support concurrent positioning ranges log

[Damien Le Moal]

Add support to discover if an ATA device supports the Concurrent
Positioning Ranges Log (address 0x47), indicating that the device is
capable of seeking to multiple different locations in parallel using
multiple actuators serving different LBA ranges.

Also add support to translate the concurrent positioning ranges log
into its equivalent Concurrent Positioning Ranges VPD page B9h in
libata-scsi.c.

The format of the Concurrent Positioning Ranges Log is defined in ACS-5
r9.

Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 drivers/ata/libata-core.c | 52 +++++++++++++++++++++++++++++++++++++++
 drivers/ata/libata-scsi.c | 48 +++++++++++++++++++++++++++++-------
 include/linux/ata.h       |  1 +
 include/linux/libata.h    | 15 +++++++++++
 4 files changed, 107 insertions(+), 9 deletions(-)

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 61c762961ca8..ab3f61ea743e 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -2363,6 +2363,57 @@ static void ata_dev_config_trusted(struct ata_device *dev)
 		dev->flags |= ATA_DFLAG_TRUSTED;
 }
 
+static void ata_dev_config_cpr(struct ata_device *dev)
+{
+	unsigned int err_mask;
+	size_t buf_len;
+	int i, nr_cpr = 0;
+	struct ata_cpr_log *cpr_log = NULL;
+	u8 *desc, *buf = NULL;
+
+	if (!ata_identify_page_supported(dev,
+				 ATA_LOG_CONCURRENT_POSITIONING_RANGES))
+		goto out;
+
+	/*
+	 * Read IDENTIFY DEVICE data log, page 0x47
+	 * (concurrent positioning ranges). We can have at most 255 32B range
+	 * descriptors plus a 64B header.
+	 */
+	buf_len = (64 + 255 * 32 + 511) & ~511;
+	buf = kzalloc(buf_len, GFP_KERNEL);
+	if (!buf)
+		goto out;
+
+	err_mask = ata_read_log_page(dev, ATA_LOG_IDENTIFY_DEVICE,
+				     ATA_LOG_CONCURRENT_POSITIONING_RANGES,
+				     buf, buf_len >> 9);
+	if (err_mask)
+		goto out;
+
+	nr_cpr = buf[0];
+	if (!nr_cpr)
+		goto out;
+
+	cpr_log = kzalloc(struct_size(cpr_log, cpr, nr_cpr), GFP_KERNEL);
+	if (!cpr_log)
+		goto out;
+
+	cpr_log->nr_cpr = nr_cpr;
+	desc = &buf[64];
+	for (i = 0; i < nr_cpr; i++, desc += 32) {
+		cpr_log->cpr[i].num = desc[0];
+		cpr_log->cpr[i].num_storage_elements = desc[1];
+		cpr_log->cpr[i].start_lba = get_unaligned_le64(&desc[8]);
+		cpr_log->cpr[i].num_lbas = get_unaligned_le64(&desc[16]);
+	}
+
+out:
+	swap(dev->cpr_log, cpr_log);
+	kfree(cpr_log);
+	kfree(buf);
+}
+
 /**
  *	ata_dev_configure - Configure the specified ATA/ATAPI device
  *	@dev: Target device to configure
@@ -2591,6 +2642,7 @@ int ata_dev_configure(struct ata_device *dev)
 		ata_dev_config_sense_reporting(dev);
 		ata_dev_config_zac(dev);
 		ata_dev_config_trusted(dev);
+		ata_dev_config_cpr(dev);
 		dev->cdb_len = 32;
 	}
 
diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index b9588c52815d..5cadbb9a8bf2 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -1937,7 +1937,7 @@ static unsigned int ata_scsiop_inq_std(struct ata_scsi_args *args, u8 *rbuf)
  */
 static unsigned int ata_scsiop_inq_00(struct ata_scsi_args *args, u8 *rbuf)
 {
-	int num_pages;
+	int i, num_pages = 0;
 	static const u8 pages[] = {
 		0x00,	/* page 0x00, this page */
 		0x80,	/* page 0x80, unit serial no page */
@@ -1947,13 +1947,17 @@ static unsigned int ata_scsiop_inq_00(struct ata_scsi_args *args, u8 *rbuf)
 		0xb1,	/* page 0xb1, block device characteristics page */
 		0xb2,	/* page 0xb2, thin provisioning page */
 		0xb6,	/* page 0xb6, zoned block device characteristics */
+		0xb9,	/* page 0xb9, concurrent positioning ranges */
 	};
 
-	num_pages = sizeof(pages);
-	if (!(args->dev->flags & ATA_DFLAG_ZAC))
-		num_pages--;
+	for (i = 0; i < sizeof(pages); i++) {
+		if (pages[i] == 0xb6 &&
+		    !(args->dev->flags & ATA_DFLAG_ZAC))
+			continue;
+		rbuf[num_pages + 4] = pages[i];
+		num_pages++;
+	}
 	rbuf[3] = num_pages;	/* number of supported VPD pages */
-	memcpy(rbuf + 4, pages, num_pages);
 	return 0;
 }
 
@@ -2163,6 +2167,26 @@ static unsigned int ata_scsiop_inq_b6(struct ata_scsi_args *args, u8 *rbuf)
 	return 0;
 }
 
+static unsigned int ata_scsiop_inq_b9(struct ata_scsi_args *args, u8 *rbuf)
+{
+	struct ata_cpr_log *cpr_log = args->dev->cpr_log;
+	u8 *desc = &rbuf[64];
+	int i;
+
+	/* SCSI Concurrent Positioning Ranges VPD page: SBC-5 rev 1 or later */
+	rbuf[1] = 0xb9;
+	put_unaligned_be16(64 + (int)cpr_log->nr_cpr * 32 - 4, &rbuf[3]);
+
+	for (i = 0; i < cpr_log->nr_cpr; i++, desc += 32) {
+		desc[0] = cpr_log->cpr[i].num;
+		desc[1] = cpr_log->cpr[i].num_storage_elements;
+		put_unaligned_be64(cpr_log->cpr[i].start_lba, &desc[8]);
+		put_unaligned_be64(cpr_log->cpr[i].num_lbas, &desc[16]);
+	}
+
+	return 0;
+}
+
 /**
  *	modecpy - Prepare response for MODE SENSE
  *	@dest: output buffer
@@ -4162,11 +4186,17 @@ void ata_scsi_simulate(struct ata_device *dev, struct scsi_cmnd *cmd)
 			ata_scsi_rbuf_fill(&args, ata_scsiop_inq_b2);
 			break;
 		case 0xb6:
-			if (dev->flags & ATA_DFLAG_ZAC) {
+			if (dev->flags & ATA_DFLAG_ZAC)
 				ata_scsi_rbuf_fill(&args, ata_scsiop_inq_b6);
-				break;
-			}
-			fallthrough;
+			else
+				ata_scsi_set_invalid_field(dev, cmd, 2, 0xff);
+			break;
+		case 0xb9:
+			if (dev->cpr_log)
+				ata_scsi_rbuf_fill(&args, ata_scsiop_inq_b9);
+			else
+				ata_scsi_set_invalid_field(dev, cmd, 2, 0xff);
+			break;
 		default:
 			ata_scsi_set_invalid_field(dev, cmd, 2, 0xff);
 			break;
diff --git a/include/linux/ata.h b/include/linux/ata.h
index 1b44f40c7700..199e47e97d64 100644
--- a/include/linux/ata.h
+++ b/include/linux/ata.h
@@ -329,6 +329,7 @@ enum {
 	ATA_LOG_SECURITY	  = 0x06,
 	ATA_LOG_SATA_SETTINGS	  = 0x08,
 	ATA_LOG_ZONED_INFORMATION = 0x09,
+	ATA_LOG_CONCURRENT_POSITIONING_RANGES = 0x47,
 
 	/* Identify device SATA settings log:*/
 	ATA_LOG_DEVSLP_OFFSET	  = 0x30,
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 3fcd24236793..b159a245d88c 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -670,6 +670,18 @@ struct ata_ering {
 	struct ata_ering_entry	ring[ATA_ERING_SIZE];
 };
 
+struct ata_cpr {
+	u8			num;
+	u8			num_storage_elements;
+	u64			start_lba;
+	u64			num_lbas;
+};
+
+struct ata_cpr_log {
+	u8			nr_cpr;
+	struct ata_cpr		cpr[];
+};
+
 struct ata_device {
 	struct ata_link		*link;
 	unsigned int		devno;		/* 0 or 1 */
@@ -729,6 +741,9 @@ struct ata_device {
 	u32			zac_zones_optimal_nonseq;
 	u32			zac_zones_max_open;
 
+	/* Concurrent positioning ranges */
+	struct ata_cpr_log	*cpr_log;
+
 	/* error history */
 	int			spdn_cnt;
 	/* ering is CLEAR_END, read comment above CLEAR_END */
-- 
2.31.1

[PATCH v4 4/5] doc: document sysfs queue/cranges attributes

[Damien Le Moal]

Update the file Documentation/block/queue-sysfs.rst to add a description
of a device queue sysfs entries related to concurrent sector ranges
(e.g. concurrent positioning ranges for multi-actuator hard-disks).

While at it, also fix a typo in this file introduction paragraph.

Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 Documentation/block/queue-sysfs.rst | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/Documentation/block/queue-sysfs.rst b/Documentation/block/queue-sysfs.rst
index 4dc7f0d499a8..757609bbb1e2 100644
--- a/Documentation/block/queue-sysfs.rst
+++ b/Documentation/block/queue-sysfs.rst
@@ -286,4 +286,32 @@ sequential zones of zoned block devices (devices with a zoned attributed
 that reports "host-managed" or "host-aware"). This value is always 0 for
 regular block devices.
 
+cranges (RO)
+------------
+
+The presence of this sub-directory of the /sys/block/xxx/queue/ directory
+indicates that the device is capable of executing requests targeting
+different sector ranges in parallel. For instance, single LUN multi-actuator
+hard-disks will likely have a cranges directory if the device correctly
+advertizes the sector ranges of its actuators.
+
+The cranges directory contains one directory per concurrent range, with each
+range described using the sector (RO) attribute file to indicate the first
+sector of the range and the nr_sectors (RO) attribute file to indicate the
+total number of sector in the range starting from the first sector.
+For example, a dual-actuator hard disk will have the following cranges
+entries.::
+
+        $ tree /sys/block/<device>/queue/cranges/
+        /sys/block/<device>/queue/cranges/
+        |-- 0
+        |   |-- nr_sectors
+        |   `-- sector
+        `-- 1
+            |-- nr_sectors
+            `-- sector
+
+The sector and nr_sectors attributes use 512B sector unit, regardless of
+the actual block size of the device.
+
 Jens Axboe <jens.axboe@oracle.com>, February 2009
-- 
2.31.1

[PATCH v4 5/5] doc: Fix typo in request queue sysfs documentation

[Damien Le Moal]

Fix a typo (are -> as) in the introduction paragraph of
Documentation/block/queue-sysfs.rst.

Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
---
 Documentation/block/queue-sysfs.rst | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Documentation/block/queue-sysfs.rst b/Documentation/block/queue-sysfs.rst
index 757609bbb1e2..25f4a768f450 100644
--- a/Documentation/block/queue-sysfs.rst
+++ b/Documentation/block/queue-sysfs.rst
@@ -4,7 +4,7 @@ Queue sysfs files
 
 This text file will detail the queue files that are located in the sysfs tree
 for each block device. Note that stacked devices typically do not export
-any settings, since their queue merely functions are a remapping target.
+any settings, since their queue merely functions as a remapping target.
 These files are the ones found in the /sys/block/xxx/queue/ directory.
 
 Files denoted with a RO postfix are readonly and the RW postfix means
-- 
2.31.1

Re: [PATCH v4 1/5] block: Add concurrent positioning ranges support

[kernel test robot]

[-- Attachment #1: Type: text/plain, Size: 3861 bytes --]

Hi Damien,

I love your patch! Perhaps something to improve:

[auto build test WARNING on block/for-next]
[also build test WARNING on mkp-scsi/for-next scsi/for-next linus/master v5.14-rc5 next-20210811]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Damien-Le-Moal/Initial-support-for-multi-actuator-HDDs/20210812-102824
base:   https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git for-next
config: hexagon-randconfig-r041-20210810 (attached as .config)
compiler: clang version 12.0.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/2055ecb9ea719e82d4db70d303fdac48c33acd47
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Damien-Le-Moal/Initial-support-for-multi-actuator-HDDs/20210812-102824
        git checkout 2055ecb9ea719e82d4db70d303fdac48c33acd47
        # save the attached .config to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross O=build_dir ARCH=hexagon SHELL=/bin/bash

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

>> block/blk-cranges.c:111: warning: expecting prototype for blk_register_cranges(). Prototype was for disk_register_cranges() instead


vim +111 block/blk-cranges.c

    99	
   100	/**
   101	 * blk_register_cranges - register with sysfs a set of concurrent ranges
   102	 * @disk:		Target disk
   103	 * @new_cranges:	New set of concurrent ranges
   104	 *
   105	 * Register with sysfs a set of concurrent ranges for @disk. If @new_cranges
   106	 * is not NULL, this set of concurrent ranges is registered and the
   107	 * old set specified by q->cranges is unregistered. Otherwise, q->cranges
   108	 * is registered if it is not already.
   109	 */
   110	int disk_register_cranges(struct gendisk *disk, struct blk_cranges *new_cranges)
 > 111	{
   112		struct request_queue *q = disk->queue;
   113		struct blk_cranges *cranges;
   114		int i, ret;
   115	
   116		lockdep_assert_held(&q->sysfs_dir_lock);
   117		lockdep_assert_held(&q->sysfs_lock);
   118	
   119		/* If a new range set is specified, unregister the old one */
   120		if (new_cranges) {
   121			if (q->cranges)
   122				disk_unregister_cranges(disk);
   123			q->cranges = new_cranges;
   124		}
   125	
   126		cranges = q->cranges;
   127		if (!cranges)
   128			return 0;
   129	
   130		/*
   131		 * At this point, cranges is the new set of sector ranges that needs
   132		 * to be registered with sysfs.
   133		 */
   134		WARN_ON(cranges->sysfs_registered);
   135		ret = kobject_init_and_add(&cranges->kobj, &blk_cranges_ktype,
   136					   &q->kobj, "%s", "cranges");
   137		if (ret) {
   138			q->cranges = NULL;
   139			kfree(cranges);
   140			return ret;
   141		}
   142	
   143		for (i = 0; i < cranges->nr_ranges; i++) {
   144			cranges->ranges[i].queue = q;
   145			ret = kobject_init_and_add(&cranges->ranges[i].kobj,
   146						   &blk_crange_ktype, &cranges->kobj,
   147						   "%d", i);
   148			if (ret) {
   149				while (--i >= 0)
   150					kobject_del(&cranges->ranges[i].kobj);
   151				kobject_del(&cranges->kobj);
   152				kobject_put(&cranges->kobj);
   153				return ret;
   154			}
   155		}
   156	
   157		cranges->sysfs_registered = true;
   158	
   159		return 0;
   160	}
   161	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

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