diff mbox series

[v3,01/15] block: Add atomic write operations to request_queue limits

Message ID 20240124113841.31824-2-john.g.garry@oracle.com (mailing list archive)
State New, archived
Headers show
Series block atomic writes | expand

Commit Message

John Garry Jan. 24, 2024, 11:38 a.m. UTC
From: Himanshu Madhani <himanshu.madhani@oracle.com>

Add the following limits:
- atomic_write_boundary_bytes
- atomic_write_max_bytes
- atomic_write_unit_max_bytes
- atomic_write_unit_min_bytes

All atomic writes limits are initialised to 0 to indicate no atomic write
support. Stacked devices are just not supported either for now.

Signed-off-by: Himanshu Madhani <himanshu.madhani@oracle.com>
#jpg: Heavy rewrite
Signed-off-by: John Garry <john.g.garry@oracle.com>
---
This will conflict with
https://lore.kernel.org/linux-nvme/20240122173645.1686078-1-hch@lst.de/T/#mf77609a2064fe9387706ce564d8246c5243eeb99,
but I will rebase when that is merged and I assume
blk_atomic_writes_update_limits() will be merged into a larger "update"
function.

 Documentation/ABI/stable/sysfs-block | 52 ++++++++++++++++++
 block/blk-settings.c                 | 79 ++++++++++++++++++++++++++++
 block/blk-sysfs.c                    | 33 ++++++++++++
 include/linux/blkdev.h               | 40 ++++++++++++++
 4 files changed, 204 insertions(+)

Comments

Christoph Hellwig Feb. 13, 2024, 6:22 a.m. UTC | #1
On Wed, Jan 24, 2024 at 11:38:27AM +0000, John Garry wrote:
> From: Himanshu Madhani <himanshu.madhani@oracle.com>
> 
> Add the following limits:
> - atomic_write_boundary_bytes
> - atomic_write_max_bytes
> - atomic_write_unit_max_bytes
> - atomic_write_unit_min_bytes
> 
> All atomic writes limits are initialised to 0 to indicate no atomic write
> support. Stacked devices are just not supported either for now.

Can you merge this with the next patch?  Splitting adding limits vs
actually using them seems rather confusing.
diff mbox series

Patch

diff --git a/Documentation/ABI/stable/sysfs-block b/Documentation/ABI/stable/sysfs-block
index 1fe9a553c37b..ac3c6b46f1a3 100644
--- a/Documentation/ABI/stable/sysfs-block
+++ b/Documentation/ABI/stable/sysfs-block
@@ -21,6 +21,58 @@  Description:
 		device is offset from the internal allocation unit's
 		natural alignment.
 
+What:		/sys/block/<disk>/atomic_write_max_bytes
+Date:		January 2024
+Contact:	Himanshu Madhani <himanshu.madhani@oracle.com>
+Description:
+		[RO] This parameter specifies the maximum atomic write
+		size reported by the device. This parameter is relevant
+		for merging of writes, where a merged atomic write
+		operation must not exceed this number of bytes.
+		This parameter may be greater to the value in
+		atomic_write_unit_max_bytes as
+		atomic_write_unit_max_bytes will be rounded down to a
+		power-of-two and atomic_write_unit_max_bytes may also be
+		limited by some other queue limits, such as max_segments.
+		This parameter - along with atomic_write_unit_min_bytes
+		and atomic_write_unit_max_bytes - will not be larger than
+		max_hw_sectors_kb, but may be larger than max_sectors_kb.
+
+
+What:		/sys/block/<disk>/atomic_write_unit_min_bytes
+Date:		January 2024
+Contact:	Himanshu Madhani <himanshu.madhani@oracle.com>
+Description:
+		[RO] This parameter specifies the smallest block which can
+		be written atomically with an atomic write operation. All
+		atomic write operations must begin at a
+		atomic_write_unit_min boundary and must be multiples of
+		atomic_write_unit_min. This value must be a power-of-two.
+
+
+What:		/sys/block/<disk>/atomic_write_unit_max_bytes
+Date:		January 2024
+Contact:	Himanshu Madhani <himanshu.madhani@oracle.com>
+Description:
+		[RO] This parameter defines the largest block which can be
+		written atomically with an atomic write operation. This
+		value must be a multiple of atomic_write_unit_min and must
+		be a power-of-two. This value will not be larger than
+		atomic_write_max_bytes.
+
+
+What:		/sys/block/<disk>/atomic_write_boundary_bytes
+Date:		January 2024
+Contact:	Himanshu Madhani <himanshu.madhani@oracle.com>
+Description:
+		[RO] A device may need to internally split I/Os which
+		straddle a given logical block address boundary. In that
+		case a single atomic write operation will be processed as
+		one of more sub-operations which each complete atomically.
+		This parameter specifies the size in bytes of the atomic
+		boundary if one is reported by the device. This value must
+		be a power-of-two.
+
 
 What:		/sys/block/<disk>/diskseq
 Date:		February 2021
diff --git a/block/blk-settings.c b/block/blk-settings.c
index 06ea91e51b8b..11c0361c2313 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -59,6 +59,13 @@  void blk_set_default_limits(struct queue_limits *lim)
 	lim->zoned = false;
 	lim->zone_write_granularity = 0;
 	lim->dma_alignment = 511;
+	lim->atomic_write_hw_max_sectors = 0;
+	lim->atomic_write_max_sectors = 0;
+	lim->atomic_write_hw_boundary_sectors = 0;
+	lim->atomic_write_hw_unit_min_sectors = 0;
+	lim->atomic_write_unit_min_sectors = 0;
+	lim->atomic_write_hw_unit_max_sectors = 0;
+	lim->atomic_write_unit_max_sectors = 0;
 }
 
 /**
@@ -101,6 +108,20 @@  void blk_queue_bounce_limit(struct request_queue *q, enum blk_bounce bounce)
 }
 EXPORT_SYMBOL(blk_queue_bounce_limit);
 
+static void blk_atomic_writes_update_limits(struct request_queue *q)
+{
+	struct queue_limits *limits = &q->limits;
+	unsigned int max_hw_sectors =
+		rounddown_pow_of_two(limits->max_hw_sectors);
+
+	limits->atomic_write_max_sectors =
+		min(limits->atomic_write_hw_max_sectors, max_hw_sectors);
+	limits->atomic_write_unit_min_sectors =
+		min(limits->atomic_write_hw_unit_min_sectors, max_hw_sectors);
+	limits->atomic_write_unit_max_sectors =
+		min(limits->atomic_write_hw_unit_max_sectors, max_hw_sectors);
+}
+
 /**
  * blk_queue_max_hw_sectors - set max sectors for a request for this queue
  * @q:  the request queue for the device
@@ -145,6 +166,8 @@  void blk_queue_max_hw_sectors(struct request_queue *q, unsigned int max_hw_secto
 				 limits->logical_block_size >> SECTOR_SHIFT);
 	limits->max_sectors = max_sectors;
 
+	blk_atomic_writes_update_limits(q);
+
 	if (!q->disk)
 		return;
 	q->disk->bdi->io_pages = max_sectors >> (PAGE_SHIFT - 9);
@@ -182,6 +205,62 @@  void blk_queue_max_discard_sectors(struct request_queue *q,
 }
 EXPORT_SYMBOL(blk_queue_max_discard_sectors);
 
+/**
+ * blk_queue_atomic_write_max_bytes - set max bytes supported by
+ * the device for atomic write operations.
+ * @q:  the request queue for the device
+ * @bytes: maximum bytes supported
+ */
+void blk_queue_atomic_write_max_bytes(struct request_queue *q,
+				      unsigned int bytes)
+{
+	q->limits.atomic_write_hw_max_sectors = bytes >> SECTOR_SHIFT;
+	blk_atomic_writes_update_limits(q);
+}
+EXPORT_SYMBOL(blk_queue_atomic_write_max_bytes);
+
+/**
+ * blk_queue_atomic_write_boundary_bytes - Device's logical block address space
+ * which an atomic write should not cross.
+ * @q:  the request queue for the device
+ * @bytes: must be a power-of-two.
+ */
+void blk_queue_atomic_write_boundary_bytes(struct request_queue *q,
+					   unsigned int bytes)
+{
+	q->limits.atomic_write_hw_boundary_sectors = bytes >> SECTOR_SHIFT;
+}
+EXPORT_SYMBOL(blk_queue_atomic_write_boundary_bytes);
+
+/**
+ * blk_queue_atomic_write_unit_min_sectors - smallest unit that can be written
+ * atomically to the device.
+ * @q:  the request queue for the device
+ * @sectors: must be a power-of-two.
+ */
+void blk_queue_atomic_write_unit_min_sectors(struct request_queue *q,
+					     unsigned int sectors)
+{
+
+	q->limits.atomic_write_hw_unit_min_sectors = sectors;
+	blk_atomic_writes_update_limits(q);
+}
+EXPORT_SYMBOL(blk_queue_atomic_write_unit_min_sectors);
+
+/*
+ * blk_queue_atomic_write_unit_max_sectors - largest unit that can be written
+ * atomically to the device.
+ * @q: the request queue for the device
+ * @sectors: must be a power-of-two.
+ */
+void blk_queue_atomic_write_unit_max_sectors(struct request_queue *q,
+					     unsigned int sectors)
+{
+	q->limits.atomic_write_hw_unit_max_sectors = sectors;
+	blk_atomic_writes_update_limits(q);
+}
+EXPORT_SYMBOL(blk_queue_atomic_write_unit_max_sectors);
+
 /**
  * blk_queue_max_secure_erase_sectors - set max sectors for a secure erase
  * @q:  the request queue for the device
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index 6b2429cad81a..3978f14f9769 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -118,6 +118,30 @@  static ssize_t queue_max_discard_segments_show(struct request_queue *q,
 	return queue_var_show(queue_max_discard_segments(q), page);
 }
 
+static ssize_t queue_atomic_write_max_bytes_show(struct request_queue *q,
+						char *page)
+{
+	return queue_var_show(queue_atomic_write_max_bytes(q), page);
+}
+
+static ssize_t queue_atomic_write_boundary_show(struct request_queue *q,
+						char *page)
+{
+	return queue_var_show(queue_atomic_write_boundary_bytes(q), page);
+}
+
+static ssize_t queue_atomic_write_unit_min_show(struct request_queue *q,
+						char *page)
+{
+	return queue_var_show(queue_atomic_write_unit_min_bytes(q), page);
+}
+
+static ssize_t queue_atomic_write_unit_max_show(struct request_queue *q,
+						char *page)
+{
+	return queue_var_show(queue_atomic_write_unit_max_bytes(q), page);
+}
+
 static ssize_t queue_max_integrity_segments_show(struct request_queue *q, char *page)
 {
 	return queue_var_show(q->limits.max_integrity_segments, page);
@@ -502,6 +526,11 @@  QUEUE_RO_ENTRY(queue_discard_max_hw, "discard_max_hw_bytes");
 QUEUE_RW_ENTRY(queue_discard_max, "discard_max_bytes");
 QUEUE_RO_ENTRY(queue_discard_zeroes_data, "discard_zeroes_data");
 
+QUEUE_RO_ENTRY(queue_atomic_write_max_bytes, "atomic_write_max_bytes");
+QUEUE_RO_ENTRY(queue_atomic_write_boundary, "atomic_write_boundary_bytes");
+QUEUE_RO_ENTRY(queue_atomic_write_unit_max, "atomic_write_unit_max_bytes");
+QUEUE_RO_ENTRY(queue_atomic_write_unit_min, "atomic_write_unit_min_bytes");
+
 QUEUE_RO_ENTRY(queue_write_same_max, "write_same_max_bytes");
 QUEUE_RO_ENTRY(queue_write_zeroes_max, "write_zeroes_max_bytes");
 QUEUE_RO_ENTRY(queue_zone_append_max, "zone_append_max_bytes");
@@ -629,6 +658,10 @@  static struct attribute *queue_attrs[] = {
 	&queue_discard_max_entry.attr,
 	&queue_discard_max_hw_entry.attr,
 	&queue_discard_zeroes_data_entry.attr,
+	&queue_atomic_write_max_bytes_entry.attr,
+	&queue_atomic_write_boundary_entry.attr,
+	&queue_atomic_write_unit_min_entry.attr,
+	&queue_atomic_write_unit_max_entry.attr,
 	&queue_write_same_max_entry.attr,
 	&queue_write_zeroes_max_entry.attr,
 	&queue_zone_append_max_entry.attr,
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 99e4f5e72213..d5490b988918 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -299,6 +299,14 @@  struct queue_limits {
 	unsigned int		discard_alignment;
 	unsigned int		zone_write_granularity;
 
+	unsigned int		atomic_write_hw_max_sectors;
+	unsigned int		atomic_write_max_sectors;
+	unsigned int		atomic_write_hw_boundary_sectors;
+	unsigned int		atomic_write_hw_unit_min_sectors;
+	unsigned int		atomic_write_unit_min_sectors;
+	unsigned int		atomic_write_hw_unit_max_sectors;
+	unsigned int		atomic_write_unit_max_sectors;
+
 	unsigned short		max_segments;
 	unsigned short		max_integrity_segments;
 	unsigned short		max_discard_segments;
@@ -885,6 +893,14 @@  void blk_queue_zone_write_granularity(struct request_queue *q,
 				      unsigned int size);
 extern void blk_queue_alignment_offset(struct request_queue *q,
 				       unsigned int alignment);
+void blk_queue_atomic_write_max_bytes(struct request_queue *q,
+				unsigned int bytes);
+void blk_queue_atomic_write_unit_max_sectors(struct request_queue *q,
+				unsigned int sectors);
+void blk_queue_atomic_write_unit_min_sectors(struct request_queue *q,
+				unsigned int sectors);
+void blk_queue_atomic_write_boundary_bytes(struct request_queue *q,
+				unsigned int bytes);
 void disk_update_readahead(struct gendisk *disk);
 extern void blk_limits_io_min(struct queue_limits *limits, unsigned int min);
 extern void blk_queue_io_min(struct request_queue *q, unsigned int min);
@@ -1291,6 +1307,30 @@  static inline int queue_dma_alignment(const struct request_queue *q)
 	return q ? q->limits.dma_alignment : 511;
 }
 
+static inline unsigned int
+queue_atomic_write_unit_max_bytes(const struct request_queue *q)
+{
+	return q->limits.atomic_write_unit_max_sectors << SECTOR_SHIFT;
+}
+
+static inline unsigned int
+queue_atomic_write_unit_min_bytes(const struct request_queue *q)
+{
+	return q->limits.atomic_write_unit_min_sectors << SECTOR_SHIFT;
+}
+
+static inline unsigned int
+queue_atomic_write_boundary_bytes(const struct request_queue *q)
+{
+	return q->limits.atomic_write_hw_boundary_sectors << SECTOR_SHIFT;
+}
+
+static inline unsigned int
+queue_atomic_write_max_bytes(const struct request_queue *q)
+{
+	return q->limits.atomic_write_max_sectors << SECTOR_SHIFT;
+}
+
 static inline unsigned int bdev_dma_alignment(struct block_device *bdev)
 {
 	return queue_dma_alignment(bdev_get_queue(bdev));