atomic queue limits updates v5

atomic queue limits updates v5

[Christoph Hellwig]

Hi Jens,

currently queue limits updates are a mess in that they are updated one
limit at a time, which makes both cross-checking them against other
limits hard, and also makes it hard to provide atomicy.

This series tries to change this by updating the whole set of queue
limits atomically.   This in done in two ways:

 - for the initial setup the queue_limits structure is simply passed to
   the queue/disk allocation helpers and applies there after validation.
 - for the (relatively few) cases that update limits at runtime a pair
   of helpers to take a snapshot of the current limits and to commit it
   after picking up the callers changes are provided.

As the series is big enough it only converts two drivers - virtio_blk as
a heavily used driver in virtualized setups, and loop as one that actually
does runtime updates while being fairly simple.  I plan to update most
drivers for this merge window, although SCSI will probably have to wait
for the next one given that it will need extensive API changes in the
LLDD and ULD interfaces.

Chances since v4:
 - fix a newly added bisection hazard
 - fix a comment
 - moar SECTOR_SIZE

Chances since v3:
 - fix a max_user_discard_sectors bisection hazard
 - fix the max_user_discard_sectors initialization for the new API.
   This led to some major refactoring, so there is a new patch and
   I've dropped the reviews for two existing ones that have major
   modifications

Chances since v2:
 - fix the physical block size default
 - use PAGE_SECTORS_SHIFT more 

Chances since v1:
 - remove a spurious NULL return in blk_alloc_queue
 - keep the existing max_discard_sectors == 0 behavior
 - drop the patch nvme discard limit update hack - it will go into
   the series updating nvme instead
 - drop a chunk_sector check
 - use PAGE_SECTORS in a few places
 - document the checks and defaults in blk_validate_limits
 - various spelling fixes

Diffstat:
 arch/um/drivers/ubd_kern.c          |    2 
 block/blk-core.c                    |   27 ++-
 block/blk-mq.c                      |   27 +--
 block/blk-settings.c                |  276 +++++++++++++++++++++++++++------
 block/blk-sysfs.c                   |   59 +++----
 block/blk.h                         |    4 
 block/bsg-lib.c                     |    2 
 block/genhd.c                       |    5 
 drivers/block/amiflop.c             |    2 
 drivers/block/aoe/aoeblk.c          |    2 
 drivers/block/ataflop.c             |    2 
 drivers/block/floppy.c              |    2 
 drivers/block/loop.c                |   75 ++++-----
 drivers/block/mtip32xx/mtip32xx.c   |    2 
 drivers/block/nbd.c                 |    2 
 drivers/block/null_blk/main.c       |    2 
 drivers/block/ps3disk.c             |    2 
 drivers/block/rbd.c                 |    2 
 drivers/block/rnbd/rnbd-clt.c       |    2 
 drivers/block/sunvdc.c              |    2 
 drivers/block/swim.c                |    2 
 drivers/block/swim3.c               |    2 
 drivers/block/ublk_drv.c            |    2 
 drivers/block/virtio_blk.c          |  299 ++++++++++++++++++------------------
 drivers/block/xen-blkfront.c        |    2 
 drivers/block/z2ram.c               |    2 
 drivers/cdrom/gdrom.c               |    2 
 drivers/memstick/core/ms_block.c    |    2 
 drivers/memstick/core/mspro_block.c |    2 
 drivers/mmc/core/queue.c            |    2 
 drivers/mtd/mtd_blkdevs.c           |    2 
 drivers/mtd/ubi/block.c             |    2 
 drivers/nvme/host/apple.c           |    2 
 drivers/nvme/host/core.c            |    8 
 drivers/s390/block/dasd_genhd.c     |    2 
 drivers/s390/block/scm_blk.c        |    2 
 drivers/scsi/scsi_scan.c            |    2 
 drivers/ufs/core/ufshcd.c           |    2 
 include/linux/blk-mq.h              |   10 -
 include/linux/blkdev.h              |   36 +++-
 40 files changed, 547 insertions(+), 337 deletions(-)

[PATCH 01/15] block: move max_{open,active}_zones to struct queue_limits

[Christoph Hellwig]

The maximum number of open and active zones is a limit on the queue
and should be places there so that we can including it in the upcoming
queue limits batch update API.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
---
 include/linux/blkdev.h | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 0058783a4c4351..251a11d2d2aeff 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -190,8 +190,6 @@ struct gendisk {
 	 * blk_mq_unfreeze_queue().
 	 */
 	unsigned int		nr_zones;
-	unsigned int		max_open_zones;
-	unsigned int		max_active_zones;
 	unsigned long		*conv_zones_bitmap;
 	unsigned long		*seq_zones_wlock;
 #endif /* CONFIG_BLK_DEV_ZONED */
@@ -308,6 +306,8 @@ struct queue_limits {
 	unsigned char		discard_misaligned;
 	unsigned char		raid_partial_stripes_expensive;
 	bool			zoned;
+	unsigned int		max_open_zones;
+	unsigned int		max_active_zones;
 
 	/*
 	 * Drivers that set dma_alignment to less than 511 must be prepared to
@@ -640,23 +640,23 @@ static inline bool disk_zone_is_seq(struct gendisk *disk, sector_t sector)
 static inline void disk_set_max_open_zones(struct gendisk *disk,
 		unsigned int max_open_zones)
 {
-	disk->max_open_zones = max_open_zones;
+	disk->queue->limits.max_open_zones = max_open_zones;
 }
 
 static inline void disk_set_max_active_zones(struct gendisk *disk,
 		unsigned int max_active_zones)
 {
-	disk->max_active_zones = max_active_zones;
+	disk->queue->limits.max_active_zones = max_active_zones;
 }
 
 static inline unsigned int bdev_max_open_zones(struct block_device *bdev)
 {
-	return bdev->bd_disk->max_open_zones;
+	return bdev->bd_disk->queue->limits.max_open_zones;
 }
 
 static inline unsigned int bdev_max_active_zones(struct block_device *bdev)
 {
-	return bdev->bd_disk->max_active_zones;
+	return bdev->bd_disk->queue->limits.max_active_zones;
 }
 
 #else /* CONFIG_BLK_DEV_ZONED */
-- 
2.39.2

[PATCH 02/15] block: refactor disk_update_readahead

[Christoph Hellwig]

Factor out a blk_apply_bdi_limits limits helper that can be used with
an explicit queue_limits argument, which will be useful later.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
---
 block/blk-settings.c | 21 ++++++++++++---------
 1 file changed, 12 insertions(+), 9 deletions(-)

diff --git a/block/blk-settings.c b/block/blk-settings.c
index 06ea91e51b8b2e..f16d3fec6658e5 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -85,6 +85,17 @@ void blk_set_stacking_limits(struct queue_limits *lim)
 }
 EXPORT_SYMBOL(blk_set_stacking_limits);
 
+static void blk_apply_bdi_limits(struct backing_dev_info *bdi,
+		struct queue_limits *lim)
+{
+	/*
+	 * For read-ahead of large files to be effective, we need to read ahead
+	 * at least twice the optimal I/O size.
+	 */
+	bdi->ra_pages = max(lim->io_opt * 2 / PAGE_SIZE, VM_READAHEAD_PAGES);
+	bdi->io_pages = lim->max_sectors >> PAGE_SECTORS_SHIFT;
+}
+
 /**
  * blk_queue_bounce_limit - set bounce buffer limit for queue
  * @q: the request queue for the device
@@ -393,15 +404,7 @@ EXPORT_SYMBOL(blk_queue_alignment_offset);
 
 void disk_update_readahead(struct gendisk *disk)
 {
-	struct request_queue *q = disk->queue;
-
-	/*
-	 * For read-ahead of large files to be effective, we need to read ahead
-	 * at least twice the optimal I/O size.
-	 */
-	disk->bdi->ra_pages =
-		max(queue_io_opt(q) * 2 / PAGE_SIZE, VM_READAHEAD_PAGES);
-	disk->bdi->io_pages = queue_max_sectors(q) >> (PAGE_SHIFT - 9);
+	blk_apply_bdi_limits(disk->bdi, &disk->queue->limits);
 }
 EXPORT_SYMBOL_GPL(disk_update_readahead);
 
-- 
2.39.2

[PATCH 03/15] block: decouple blk_set_stacking_limits from blk_set_default_limits

[Christoph Hellwig]

blk_set_stacking_limits uses very little from blk_set_default_limits.
Open code these initializations in preparation for rewriting
blk_set_default_limits.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
---
 block/blk-settings.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/block/blk-settings.c b/block/blk-settings.c
index f16d3fec6658e5..24042f6b33d54e 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -65,13 +65,18 @@ void blk_set_default_limits(struct queue_limits *lim)
  * blk_set_stacking_limits - set default limits for stacking devices
  * @lim:  the queue_limits structure to reset
  *
- * Description:
- *   Returns a queue_limit struct to its default state. Should be used
- *   by stacking drivers like DM that have no internal limits.
+ * Prepare queue limits for applying limits from underlying devices using
+ * blk_stack_limits().
  */
 void blk_set_stacking_limits(struct queue_limits *lim)
 {
-	blk_set_default_limits(lim);
+	memset(lim, 0, sizeof(*lim));
+	lim->logical_block_size = SECTOR_SIZE;
+	lim->physical_block_size = SECTOR_SIZE;
+	lim->io_min = SECTOR_SIZE;
+	lim->discard_granularity = SECTOR_SIZE;
+	lim->dma_alignment = SECTOR_SIZE - 1;
+	lim->seg_boundary_mask = BLK_SEG_BOUNDARY_MASK;
 
 	/* Inherit limits from component devices */
 	lim->max_segments = USHRT_MAX;
-- 
2.39.2

[PATCH 04/15] block: add an API to atomically update queue limits

[Christoph Hellwig]

Add a new queue_limits_{start,commit}_update pair of functions that
allows taking an atomic snapshot of queue limits, update it, and
commit it if it passes validity checking.  Also use the low-level
validation helper to implement blk_set_default_limits instead of
duplicating the initialization.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
---
 block/blk-core.c       |   1 +
 block/blk-settings.c   | 228 ++++++++++++++++++++++++++++++++++-------
 block/blk.h            |   2 +-
 include/linux/blkdev.h |  23 +++++
 4 files changed, 217 insertions(+), 37 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index 2b11d8325fde68..cb56724a8dfb25 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -425,6 +425,7 @@ struct request_queue *blk_alloc_queue(int node_id)
 	mutex_init(&q->debugfs_mutex);
 	mutex_init(&q->sysfs_lock);
 	mutex_init(&q->sysfs_dir_lock);
+	mutex_init(&q->limits_lock);
 	mutex_init(&q->rq_qos_mutex);
 	spin_lock_init(&q->queue_lock);
 
diff --git a/block/blk-settings.c b/block/blk-settings.c
index 24042f6b33d54e..786b369ca59995 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -25,42 +25,6 @@ void blk_queue_rq_timeout(struct request_queue *q, unsigned int timeout)
 }
 EXPORT_SYMBOL_GPL(blk_queue_rq_timeout);
 
-/**
- * blk_set_default_limits - reset limits to default values
- * @lim:  the queue_limits structure to reset
- *
- * Description:
- *   Returns a queue_limit struct to its default state.
- */
-void blk_set_default_limits(struct queue_limits *lim)
-{
-	lim->max_segments = BLK_MAX_SEGMENTS;
-	lim->max_discard_segments = 1;
-	lim->max_integrity_segments = 0;
-	lim->seg_boundary_mask = BLK_SEG_BOUNDARY_MASK;
-	lim->virt_boundary_mask = 0;
-	lim->max_segment_size = BLK_MAX_SEGMENT_SIZE;
-	lim->max_sectors = lim->max_hw_sectors = BLK_SAFE_MAX_SECTORS;
-	lim->max_user_sectors = lim->max_dev_sectors = 0;
-	lim->chunk_sectors = 0;
-	lim->max_write_zeroes_sectors = 0;
-	lim->max_zone_append_sectors = 0;
-	lim->max_discard_sectors = 0;
-	lim->max_hw_discard_sectors = 0;
-	lim->max_secure_erase_sectors = 0;
-	lim->discard_granularity = 512;
-	lim->discard_alignment = 0;
-	lim->discard_misaligned = 0;
-	lim->logical_block_size = lim->physical_block_size = lim->io_min = 512;
-	lim->bounce = BLK_BOUNCE_NONE;
-	lim->alignment_offset = 0;
-	lim->io_opt = 0;
-	lim->misaligned = 0;
-	lim->zoned = false;
-	lim->zone_write_granularity = 0;
-	lim->dma_alignment = 511;
-}
-
 /**
  * blk_set_stacking_limits - set default limits for stacking devices
  * @lim:  the queue_limits structure to reset
@@ -101,6 +65,198 @@ static void blk_apply_bdi_limits(struct backing_dev_info *bdi,
 	bdi->io_pages = lim->max_sectors >> PAGE_SECTORS_SHIFT;
 }
 
+static int blk_validate_zoned_limits(struct queue_limits *lim)
+{
+	if (!lim->zoned) {
+		if (WARN_ON_ONCE(lim->max_open_zones) ||
+		    WARN_ON_ONCE(lim->max_active_zones) ||
+		    WARN_ON_ONCE(lim->zone_write_granularity) ||
+		    WARN_ON_ONCE(lim->max_zone_append_sectors))
+			return -EINVAL;
+		return 0;
+	}
+
+	if (WARN_ON_ONCE(!IS_ENABLED(CONFIG_BLK_DEV_ZONED)))
+		return -EINVAL;
+
+	if (lim->zone_write_granularity < lim->logical_block_size)
+		lim->zone_write_granularity = lim->logical_block_size;
+
+	if (lim->max_zone_append_sectors) {
+		/*
+		 * The Zone Append size is limited by the maximum I/O size
+		 * and the zone size given that it can't span zones.
+		 */
+		lim->max_zone_append_sectors =
+			min3(lim->max_hw_sectors,
+			     lim->max_zone_append_sectors,
+			     lim->chunk_sectors);
+	}
+
+	return 0;
+}
+
+/*
+ * Check that the limits in lim are valid, initialize defaults for unset
+ * values, and cap values based on others where needed.
+ */
+static int blk_validate_limits(struct queue_limits *lim)
+{
+	unsigned int max_hw_sectors;
+
+	/*
+	 * Unless otherwise specified, default to 512 byte logical blocks and a
+	 * physical block size equal to the logical block size.
+	 */
+	if (!lim->logical_block_size)
+		lim->logical_block_size = SECTOR_SIZE;
+	if (lim->physical_block_size < lim->logical_block_size)
+		lim->physical_block_size = lim->logical_block_size;
+
+	/*
+	 * The minimum I/O size defaults to the physical block size unless
+	 * explicitly overridden.
+	 */
+	if (lim->io_min < lim->physical_block_size)
+		lim->io_min = lim->physical_block_size;
+
+	/*
+	 * max_hw_sectors has a somewhat weird default for historical reason,
+	 * but driver really should set their own instead of relying on this
+	 * value.
+	 *
+	 * The block layer relies on the fact that every driver can
+	 * handle at lest a page worth of data per I/O, and needs the value
+	 * aligned to the logical block size.
+	 */
+	if (!lim->max_hw_sectors)
+		lim->max_hw_sectors = BLK_SAFE_MAX_SECTORS;
+	if (WARN_ON_ONCE(lim->max_hw_sectors < PAGE_SECTORS))
+		return -EINVAL;
+	lim->max_hw_sectors = round_down(lim->max_hw_sectors,
+			lim->logical_block_size >> SECTOR_SHIFT);
+
+	/*
+	 * The actual max_sectors value is a complex beast and also takes the
+	 * max_dev_sectors value (set by SCSI ULPs) and a user configurable
+	 * value into account.  The ->max_sectors value is always calculated
+	 * from these, so directly setting it won't have any effect.
+	 */
+	max_hw_sectors = min_not_zero(lim->max_hw_sectors,
+				lim->max_dev_sectors);
+	if (lim->max_user_sectors) {
+		if (lim->max_user_sectors > max_hw_sectors ||
+		    lim->max_user_sectors < PAGE_SIZE / SECTOR_SIZE)
+			return -EINVAL;
+		lim->max_sectors = min(max_hw_sectors, lim->max_user_sectors);
+	} else {
+		lim->max_sectors = min(max_hw_sectors, BLK_DEF_MAX_SECTORS_CAP);
+	}
+	lim->max_sectors = round_down(lim->max_sectors,
+			lim->logical_block_size >> SECTOR_SHIFT);
+
+	/*
+	 * Random default for the maximum number of segments.  Driver should not
+	 * rely on this and set their own.
+	 */
+	if (!lim->max_segments)
+		lim->max_segments = BLK_MAX_SEGMENTS;
+
+	lim->max_discard_sectors = lim->max_hw_discard_sectors;
+	if (!lim->max_discard_segments)
+		lim->max_discard_segments = 1;
+
+	if (lim->discard_granularity < lim->physical_block_size)
+		lim->discard_granularity = lim->physical_block_size;
+
+	/*
+	 * By default there is no limit on the segment boundary alignment,
+	 * but if there is one it can't be smaller than the page size as
+	 * that would break all the normal I/O patterns.
+	 */
+	if (!lim->seg_boundary_mask)
+		lim->seg_boundary_mask = BLK_SEG_BOUNDARY_MASK;
+	if (WARN_ON_ONCE(lim->seg_boundary_mask < PAGE_SIZE - 1))
+		return -EINVAL;
+
+	/*
+	 * The maximum segment size has an odd historic 64k default that
+	 * drivers probably should override.  Just like the I/O size we
+	 * require drivers to at least handle a full page per segment.
+	 */
+	if (!lim->max_segment_size)
+		lim->max_segment_size = BLK_MAX_SEGMENT_SIZE;
+	if (WARN_ON_ONCE(lim->max_segment_size < PAGE_SIZE))
+		return -EINVAL;
+
+	/*
+	 * Devices that require a virtual boundary do not support scatter/gather
+	 * I/O natively, but instead require a descriptor list entry for each
+	 * page (which might not be identical to the Linux PAGE_SIZE).  Because
+	 * of that they are not limited by our notion of "segment size".
+	 */
+	if (lim->virt_boundary_mask) {
+		if (WARN_ON_ONCE(lim->max_segment_size &&
+				 lim->max_segment_size != UINT_MAX))
+			return -EINVAL;
+		lim->max_segment_size = UINT_MAX;
+	}
+
+	/*
+	 * We require drivers to at least do logical block aligned I/O, but
+	 * historically could not check for that due to the separate calls
+	 * to set the limits.  Once the transition is finished the check
+	 * below should be narrowed down to check the logical block size.
+	 */
+	if (!lim->dma_alignment)
+		lim->dma_alignment = SECTOR_SIZE - 1;
+	if (WARN_ON_ONCE(lim->dma_alignment > PAGE_SIZE))
+		return -EINVAL;
+
+	if (lim->alignment_offset) {
+		lim->alignment_offset &= (lim->physical_block_size - 1);
+		lim->misaligned = 0;
+	}
+
+	return blk_validate_zoned_limits(lim);
+}
+
+/*
+ * Set the default limits for a newly allocated queue.  @lim contains the
+ * initial limits set by the driver, which could be no limit in which case
+ * all fields are cleared to zero.
+ */
+int blk_set_default_limits(struct queue_limits *lim)
+{
+	return blk_validate_limits(lim);
+}
+
+/**
+ * queue_limits_commit_update - commit an atomic update of queue limits
+ * @q:		queue to update
+ * @lim:	limits to apply
+ *
+ * Apply the limits in @lim that were obtained from queue_limits_start_update()
+ * and updated by the caller to @q.
+ *
+ * Returns 0 if successful, else a negative error code.
+ */
+int queue_limits_commit_update(struct request_queue *q,
+		struct queue_limits *lim)
+	__releases(q->limits_lock)
+{
+	int error = blk_validate_limits(lim);
+
+	if (!error) {
+		q->limits = *lim;
+		if (q->disk)
+			blk_apply_bdi_limits(q->disk->bdi, lim);
+	}
+	mutex_unlock(&q->limits_lock);
+	return error;
+}
+EXPORT_SYMBOL_GPL(queue_limits_commit_update);
+
 /**
  * blk_queue_bounce_limit - set bounce buffer limit for queue
  * @q: the request queue for the device
diff --git a/block/blk.h b/block/blk.h
index 913c93838a01bf..43c7e9180b3028 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -330,7 +330,7 @@ void blk_rq_set_mixed_merge(struct request *rq);
 bool blk_rq_merge_ok(struct request *rq, struct bio *bio);
 enum elv_merge blk_try_merge(struct request *rq, struct bio *bio);
 
-void blk_set_default_limits(struct queue_limits *lim);
+int blk_set_default_limits(struct queue_limits *lim);
 int blk_dev_init(void);
 
 /*
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 251a11d2d2aeff..d41d7fe934578f 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -474,6 +474,7 @@ struct request_queue {
 
 	struct mutex		sysfs_lock;
 	struct mutex		sysfs_dir_lock;
+	struct mutex		limits_lock;
 
 	/*
 	 * for reusing dead hctx instance in case of updating
@@ -862,6 +863,28 @@ static inline unsigned int blk_chunk_sectors_left(sector_t offset,
 	return chunk_sectors - (offset & (chunk_sectors - 1));
 }
 
+/**
+ * queue_limits_start_update - start an atomic update of queue limits
+ * @q:		queue to update
+ *
+ * This functions starts an atomic update of the queue limits.  It takes a lock
+ * to prevent other updates and returns a snapshot of the current limits that
+ * the caller can modify.  The caller must call queue_limits_commit_update()
+ * to finish the update.
+ *
+ * Context: process context.  The caller must have frozen the queue or ensured
+ * that there is outstanding I/O by other means.
+ */
+static inline struct queue_limits
+queue_limits_start_update(struct request_queue *q)
+	__acquires(q->limits_lock)
+{
+	mutex_lock(&q->limits_lock);
+	return q->limits;
+}
+int queue_limits_commit_update(struct request_queue *q,
+		struct queue_limits *lim);
+
 /*
  * Access functions for manipulating queue properties
  */
-- 
2.39.2

Re: [PATCH 04/15] block: add an API to atomically update queue limits

[Hannes Reinecke]

On 2/13/24 08:34, Christoph Hellwig wrote:
> Add a new queue_limits_{start,commit}_update pair of functions that
> allows taking an atomic snapshot of queue limits, update it, and
> commit it if it passes validity checking.  Also use the low-level
> validation helper to implement blk_set_default_limits instead of
> duplicating the initialization.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
> ---
>   block/blk-core.c       |   1 +
>   block/blk-settings.c   | 228 ++++++++++++++++++++++++++++++++++-------
>   block/blk.h            |   2 +-
>   include/linux/blkdev.h |  23 +++++
>   4 files changed, 217 insertions(+), 37 deletions(-)
> 
Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes

Re: [PATCH 04/15] block: add an API to atomically update queue limits

[Christian Lamparter]

Hi,

got a WARNING splatch (=> boot harddrive is inaccessible - device fails to boot) 

------------[ cut here ]------------
WARNING: CPU: 0 PID: 29 at block/blk-settings.c:185 blk_validate_limits+0x154/0x294
Modules linked in:
CPU: 0 PID: 29 Comm: kworker/u4:2 Tainted: G        W          6.10.0+ #1
Hardware name: MyBook Live APM821XX 0x12c41c83 PowerPC 44x Platform
Workqueue: async async_run_entry_fn
NIP:  c02f1f00 LR: c02eef3c CTR: 00000000
REGS: c114bbc0 TRAP: 0700   Tainted: G        W           (6.10.0+)
MSR:  0002b000 <CE,EE,FP,ME>  CR: 84000008  XER: 00000000

GPR00: c02eef28 c114bcb0 c116cf40 c114bda8 00000082 ffffffff ffffffff 00000200
GPR08: 00000200 0000ffff 00001fff c114bc80 44000008 00000000 c00433f0 c119b440
GPR16: 00000000 00000000 00000000 00000000 c105d505 c1101880 c11b6250 00000001
GPR24: 00000000 c0ab0000 c114bda8 ffffffff c0a1eb68 00000000 00000014 c1b683d0
NIP [c02f1f00] blk_validate_limits+0x154/0x294
LR [c02eef3c] blk_alloc_queue+0x80/0x1f0
Call Trace:
[c114bcb0] [c02ffa54] blk_alloc_queue_stats+0x20/0x48 (unreliable)
[c114bcc0] [c02eef28] blk_alloc_queue+0x6c/0x1f0
[c114bcf0] [c02fde24] blk_mq_alloc_queue+0x50/0xa8
[c114bd90] [c04393b4] scsi_alloc_sdev+0x190/0x2b8
[c114be40] [c04395a8] scsi_probe_and_add_lun+0xcc/0x2a0
[c114bea0] [c043a008] __scsi_add_device+0xe4/0x134
[c114bee0] [c045296c] ata_scsi_scan_host+0x84/0x27c
[c114bf30] [c0048158] async_run_entry_fn+0x34/0xcc
[c114bf50] [c003c800] process_scheduled_works+0x170/0x244
[c114bf90] [c003cc48] worker_thread+0x184/0x1d4
[c114bfc0] [c00434bc] kthread+0xcc/0xd0
[c114bff0] [c000c210] start_kernel_thread+0x10/0x14
Code: 81430050 7c085040 40810008 91030050 81430004 2c0a0000 40820010 3940ffff 91430004 48000014 280a3ffe 41a1000c <0fe00000> 48000130 80c30008 81430020
---[ end trace 0000000000000000 ]---
scsi_alloc_sdev: Allocation failure during SCSI scanning, some SCSI devices might not be configured

---

This is due to this patch adds
| /*
|   * By default there is no limit on the segment boundary alignment,
|   * but if there is one it can't be smaller than the page size as
|   * that would break all the normal I/O patterns.
|   */
|   if (!lim->seg_boundary_mask)
|           lim->seg_boundary_mask = BLK_SEG_BOUNDARY_MASK;
|   if (WARN_ON_ONCE(lim->seg_boundary_mask < PAGE_SIZE - 1)) <----- this warning gets triggered
|          return -EINVAL;

My guess is that this is caused by the kernel has a 16K page size.

CONFIG_HAVE_PAGE_SIZE_16KB=y
CONFIG_PAGE_SIZE_16KB=y
CONFIG_PAGE_SIZE_LESS_THAN_64KB=y
CONFIG_PAGE_SIZE_LESS_THAN_256KB=y
CONFIG_PAGE_SHIFT=14

This worked fine (sata driver is sata_dwc_460ex.c) in the past (and using 16K pages was
slightly faster than 4k pages)... and yes: using a 4K page size works (as in: device boots again).

Regards,
Christian

[PATCH 05/15] block: use queue_limits_commit_update in queue_max_sectors_store

[Christoph Hellwig]

Convert queue_max_sectors_store to use queue_limits_commit_update to
check and update the max_sectors limit and freeze the queue before
doing so to ensure we don't have requests in flight while changing
the limits.

Note that this removes the previously held queue_lock that doesn't
protect against any other reader or writer.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
---
 block/blk-sysfs.c | 37 ++++++++++++-------------------------
 1 file changed, 12 insertions(+), 25 deletions(-)

diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index 6b2429cad81af1..26607f9825cb05 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -226,35 +226,22 @@ static ssize_t queue_zone_append_max_show(struct request_queue *q, char *page)
 static ssize_t
 queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
 {
-	unsigned long var;
-	unsigned int max_sectors_kb,
-		max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1,
-			page_kb = 1 << (PAGE_SHIFT - 10);
-	ssize_t ret = queue_var_store(&var, page, count);
+	unsigned long max_sectors_kb;
+	struct queue_limits lim;
+	ssize_t ret;
+	int err;
 
+	ret = queue_var_store(&max_sectors_kb, page, count);
 	if (ret < 0)
 		return ret;
 
-	max_sectors_kb = (unsigned int)var;
-	max_hw_sectors_kb = min_not_zero(max_hw_sectors_kb,
-					 q->limits.max_dev_sectors >> 1);
-	if (max_sectors_kb == 0) {
-		q->limits.max_user_sectors = 0;
-		max_sectors_kb = min(max_hw_sectors_kb,
-				     BLK_DEF_MAX_SECTORS_CAP >> 1);
-	} else {
-		if (max_sectors_kb > max_hw_sectors_kb ||
-		    max_sectors_kb < page_kb)
-			return -EINVAL;
-		q->limits.max_user_sectors = max_sectors_kb << 1;
-	}
-
-	spin_lock_irq(&q->queue_lock);
-	q->limits.max_sectors = max_sectors_kb << 1;
-	if (q->disk)
-		q->disk->bdi->io_pages = max_sectors_kb >> (PAGE_SHIFT - 10);
-	spin_unlock_irq(&q->queue_lock);
-
+	blk_mq_freeze_queue(q);
+	lim = queue_limits_start_update(q);
+	lim.max_user_sectors = max_sectors_kb << 1;
+	err = queue_limits_commit_update(q, &lim);
+	blk_mq_unfreeze_queue(q);
+	if (err)
+		return err;
 	return ret;
 }
 
-- 
2.39.2

[PATCH 06/15] block: add a max_user_discard_sectors queue limit

[Christoph Hellwig]

Add a new max_user_discard_sectors limit that mirrors max_user_sectors
and stores the value that the user manually set.  This now allows
updates of the max_hw_discard_sectors to not worry about the user
limit.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
---
 block/blk-settings.c   | 18 +++++++++++++++---
 block/blk-sysfs.c      | 17 ++++++++---------
 include/linux/blkdev.h |  1 +
 3 files changed, 24 insertions(+), 12 deletions(-)

diff --git a/block/blk-settings.c b/block/blk-settings.c
index 786b369ca59995..c4406aacc0efc6 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -51,6 +51,7 @@ void blk_set_stacking_limits(struct queue_limits *lim)
 	lim->max_dev_sectors = UINT_MAX;
 	lim->max_write_zeroes_sectors = UINT_MAX;
 	lim->max_zone_append_sectors = UINT_MAX;
+	lim->max_user_discard_sectors = UINT_MAX;
 }
 EXPORT_SYMBOL(blk_set_stacking_limits);
 
@@ -162,7 +163,9 @@ static int blk_validate_limits(struct queue_limits *lim)
 	if (!lim->max_segments)
 		lim->max_segments = BLK_MAX_SEGMENTS;
 
-	lim->max_discard_sectors = lim->max_hw_discard_sectors;
+	lim->max_discard_sectors =
+		min(lim->max_hw_discard_sectors, lim->max_user_discard_sectors);
+
 	if (!lim->max_discard_segments)
 		lim->max_discard_segments = 1;
 
@@ -228,6 +231,12 @@ static int blk_validate_limits(struct queue_limits *lim)
  */
 int blk_set_default_limits(struct queue_limits *lim)
 {
+	/*
+	 * Most defaults are set by capping the bounds in blk_validate_limits,
+	 * but max_user_discard_sectors is special and needs an explicit
+	 * initialization to the max value here.
+	 */
+	lim->max_user_discard_sectors = UINT_MAX;
 	return blk_validate_limits(lim);
 }
 
@@ -349,8 +358,11 @@ EXPORT_SYMBOL(blk_queue_chunk_sectors);
 void blk_queue_max_discard_sectors(struct request_queue *q,
 		unsigned int max_discard_sectors)
 {
-	q->limits.max_hw_discard_sectors = max_discard_sectors;
-	q->limits.max_discard_sectors = max_discard_sectors;
+	struct queue_limits *lim = &q->limits;
+
+	lim->max_hw_discard_sectors = max_discard_sectors;
+	lim->max_discard_sectors =
+		min(max_discard_sectors, lim->max_user_discard_sectors);
 }
 EXPORT_SYMBOL(blk_queue_max_discard_sectors);
 
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index 26607f9825cb05..a1ec27f0ba4150 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -174,23 +174,22 @@ static ssize_t queue_discard_max_show(struct request_queue *q, char *page)
 static ssize_t queue_discard_max_store(struct request_queue *q,
 				       const char *page, size_t count)
 {
-	unsigned long max_discard;
-	ssize_t ret = queue_var_store(&max_discard, page, count);
+	unsigned long max_discard_bytes;
+	ssize_t ret;
 
+	ret = queue_var_store(&max_discard_bytes, page, count);
 	if (ret < 0)
 		return ret;
 
-	if (max_discard & (q->limits.discard_granularity - 1))
+	if (max_discard_bytes & (q->limits.discard_granularity - 1))
 		return -EINVAL;
 
-	max_discard >>= 9;
-	if (max_discard > UINT_MAX)
+	if ((max_discard_bytes >> SECTOR_SHIFT) > UINT_MAX)
 		return -EINVAL;
 
-	if (max_discard > q->limits.max_hw_discard_sectors)
-		max_discard = q->limits.max_hw_discard_sectors;
-
-	q->limits.max_discard_sectors = max_discard;
+	q->limits.max_user_discard_sectors = max_discard_bytes >> SECTOR_SHIFT;
+	q->limits.max_discard_sectors = min(q->limits.max_hw_discard_sectors,
+					    q->limits.max_user_discard_sectors);
 	return ret;
 }
 
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index d41d7fe934578f..45746ba73670e8 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -291,6 +291,7 @@ struct queue_limits {
 	unsigned int		io_opt;
 	unsigned int		max_discard_sectors;
 	unsigned int		max_hw_discard_sectors;
+	unsigned int		max_user_discard_sectors;
 	unsigned int		max_secure_erase_sectors;
 	unsigned int		max_write_zeroes_sectors;
 	unsigned int		max_zone_append_sectors;
-- 
2.39.2

[PATCH 07/15] block: use queue_limits_commit_update in queue_discard_max_store

[Christoph Hellwig]

Convert queue_discard_max_store to use queue_limits_commit_update to
check and update the max_discard_sectors limit and freeze the queue
before doing so to ensure we don't have requests in flight while
changing the limits.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
---
 block/blk-sysfs.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index a1ec27f0ba4150..8c8f69d8ba48ee 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -175,7 +175,9 @@ static ssize_t queue_discard_max_store(struct request_queue *q,
 				       const char *page, size_t count)
 {
 	unsigned long max_discard_bytes;
+	struct queue_limits lim;
 	ssize_t ret;
+	int err;
 
 	ret = queue_var_store(&max_discard_bytes, page, count);
 	if (ret < 0)
@@ -187,9 +189,14 @@ static ssize_t queue_discard_max_store(struct request_queue *q,
 	if ((max_discard_bytes >> SECTOR_SHIFT) > UINT_MAX)
 		return -EINVAL;
 
-	q->limits.max_user_discard_sectors = max_discard_bytes >> SECTOR_SHIFT;
-	q->limits.max_discard_sectors = min(q->limits.max_hw_discard_sectors,
-					    q->limits.max_user_discard_sectors);
+	blk_mq_freeze_queue(q);
+	lim = queue_limits_start_update(q);
+	lim.max_user_discard_sectors = max_discard_bytes >> SECTOR_SHIFT;
+	err = queue_limits_commit_update(q, &lim);
+	blk_mq_unfreeze_queue(q);
+
+	if (err)
+		return err;
 	return ret;
 }
 
-- 
2.39.2

[PATCH 08/15] block: pass a queue_limits argument to blk_alloc_queue

[Christoph Hellwig]

Pass a queue_limits to blk_alloc_queue and apply it after validating and
capping the values using blk_validate_limits.  This will allow allocating
queues with valid queue limits instead of setting the values one at a
time later.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
---
 block/blk-core.c | 26 ++++++++++++++++++--------
 block/blk-mq.c   |  7 ++++---
 block/blk.h      |  2 +-
 block/genhd.c    |  5 +++--
 4 files changed, 26 insertions(+), 14 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index cb56724a8dfb25..a16b5abdbbf56f 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -394,24 +394,34 @@ static void blk_timeout_work(struct work_struct *work)
 {
 }
 
-struct request_queue *blk_alloc_queue(int node_id)
+struct request_queue *blk_alloc_queue(struct queue_limits *lim, int node_id)
 {
 	struct request_queue *q;
+	int error;
 
 	q = kmem_cache_alloc_node(blk_requestq_cachep, GFP_KERNEL | __GFP_ZERO,
 				  node_id);
 	if (!q)
-		return NULL;
+		return ERR_PTR(-ENOMEM);
 
 	q->last_merge = NULL;
 
 	q->id = ida_alloc(&blk_queue_ida, GFP_KERNEL);
-	if (q->id < 0)
+	if (q->id < 0) {
+		error = q->id;
 		goto fail_q;
+	}
 
 	q->stats = blk_alloc_queue_stats();
-	if (!q->stats)
+	if (!q->stats) {
+		error = -ENOMEM;
 		goto fail_id;
+	}
+
+	error = blk_set_default_limits(lim);
+	if (error)
+		goto fail_stats;
+	q->limits = *lim;
 
 	q->node = node_id;
 
@@ -436,12 +446,12 @@ struct request_queue *blk_alloc_queue(int node_id)
 	 * Init percpu_ref in atomic mode so that it's faster to shutdown.
 	 * See blk_register_queue() for details.
 	 */
-	if (percpu_ref_init(&q->q_usage_counter,
+	error = percpu_ref_init(&q->q_usage_counter,
 				blk_queue_usage_counter_release,
-				PERCPU_REF_INIT_ATOMIC, GFP_KERNEL))
+				PERCPU_REF_INIT_ATOMIC, GFP_KERNEL);
+	if (error)
 		goto fail_stats;
 
-	blk_set_default_limits(&q->limits);
 	q->nr_requests = BLKDEV_DEFAULT_RQ;
 
 	return q;
@@ -452,7 +462,7 @@ struct request_queue *blk_alloc_queue(int node_id)
 	ida_free(&blk_queue_ida, q->id);
 fail_q:
 	kmem_cache_free(blk_requestq_cachep, q);
-	return NULL;
+	return ERR_PTR(error);
 }
 
 /**
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 6d2f7b5caa01d8..9dd8055cc5246d 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -4086,12 +4086,13 @@ void blk_mq_release(struct request_queue *q)
 static struct request_queue *blk_mq_init_queue_data(struct blk_mq_tag_set *set,
 		void *queuedata)
 {
+	struct queue_limits lim = { };
 	struct request_queue *q;
 	int ret;
 
-	q = blk_alloc_queue(set->numa_node);
-	if (!q)
-		return ERR_PTR(-ENOMEM);
+	q = blk_alloc_queue(&lim, set->numa_node);
+	if (IS_ERR(q))
+		return q;
 	q->queuedata = queuedata;
 	ret = blk_mq_init_allocated_queue(set, q);
 	if (ret) {
diff --git a/block/blk.h b/block/blk.h
index 43c7e9180b3028..7c30e2ac8ebcd3 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -448,7 +448,7 @@ static inline void bio_release_page(struct bio *bio, struct page *page)
 		unpin_user_page(page);
 }
 
-struct request_queue *blk_alloc_queue(int node_id);
+struct request_queue *blk_alloc_queue(struct queue_limits *lim, int node_id);
 
 int disk_scan_partitions(struct gendisk *disk, blk_mode_t mode);
 
diff --git a/block/genhd.c b/block/genhd.c
index d74fb5b4ae6818..7a8fd57c51f73c 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -1393,11 +1393,12 @@ struct gendisk *__alloc_disk_node(struct request_queue *q, int node_id,
 
 struct gendisk *__blk_alloc_disk(int node, struct lock_class_key *lkclass)
 {
+	struct queue_limits lim = { };
 	struct request_queue *q;
 	struct gendisk *disk;
 
-	q = blk_alloc_queue(node);
-	if (!q)
+	q = blk_alloc_queue(&lim, node);
+	if (IS_ERR(q))
 		return NULL;
 
 	disk = __alloc_disk_node(q, node, lkclass);
-- 
2.39.2

Re: [PATCH 08/15] block: pass a queue_limits argument to blk_alloc_queue

[Hannes Reinecke]

On 2/13/24 08:34, Christoph Hellwig wrote:
> Pass a queue_limits to blk_alloc_queue and apply it after validating and
> capping the values using blk_validate_limits.  This will allow allocating
> queues with valid queue limits instead of setting the values one at a
> time later.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
> ---
>   block/blk-core.c | 26 ++++++++++++++++++--------
>   block/blk-mq.c   |  7 ++++---
>   block/blk.h      |  2 +-
>   block/genhd.c    |  5 +++--
>   4 files changed, 26 insertions(+), 14 deletions(-)
> 
Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes

[PATCH 09/15] block: pass a queue_limits argument to blk_mq_init_queue

[Christoph Hellwig]

Pass a queue_limits to blk_mq_init_queue and apply it if non-NULL.  This
will allow allocating queues with valid queue limits instead of setting
the values one at a time later.

Also rename the function to blk_mq_alloc_queue as that is a much better
name for a function that allocates a queue and always pass the queuedata
argument instead of having a separate version for the extra argument.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
---
 block/blk-mq.c            | 21 ++++++++-------------
 block/bsg-lib.c           |  2 +-
 drivers/nvme/host/apple.c |  2 +-
 drivers/nvme/host/core.c  |  6 +++---
 drivers/scsi/scsi_scan.c  |  2 +-
 drivers/ufs/core/ufshcd.c |  2 +-
 include/linux/blk-mq.h    |  3 ++-
 7 files changed, 17 insertions(+), 21 deletions(-)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 9dd8055cc5246d..f6499bbd89be90 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -4083,14 +4083,14 @@ void blk_mq_release(struct request_queue *q)
 	blk_mq_sysfs_deinit(q);
 }
 
-static struct request_queue *blk_mq_init_queue_data(struct blk_mq_tag_set *set,
-		void *queuedata)
+struct request_queue *blk_mq_alloc_queue(struct blk_mq_tag_set *set,
+		struct queue_limits *lim, void *queuedata)
 {
-	struct queue_limits lim = { };
+	struct queue_limits default_lim = { };
 	struct request_queue *q;
 	int ret;
 
-	q = blk_alloc_queue(&lim, set->numa_node);
+	q = blk_alloc_queue(lim ? lim : &default_lim, set->numa_node);
 	if (IS_ERR(q))
 		return q;
 	q->queuedata = queuedata;
@@ -4101,20 +4101,15 @@ static struct request_queue *blk_mq_init_queue_data(struct blk_mq_tag_set *set,
 	}
 	return q;
 }
-
-struct request_queue *blk_mq_init_queue(struct blk_mq_tag_set *set)
-{
-	return blk_mq_init_queue_data(set, NULL);
-}
-EXPORT_SYMBOL(blk_mq_init_queue);
+EXPORT_SYMBOL(blk_mq_alloc_queue);
 
 /**
  * blk_mq_destroy_queue - shutdown a request queue
  * @q: request queue to shutdown
  *
- * This shuts down a request queue allocated by blk_mq_init_queue(). All future
+ * This shuts down a request queue allocated by blk_mq_alloc_queue(). All future
  * requests will be failed with -ENODEV. The caller is responsible for dropping
- * the reference from blk_mq_init_queue() by calling blk_put_queue().
+ * the reference from blk_mq_alloc_queue() by calling blk_put_queue().
  *
  * Context: can sleep
  */
@@ -4141,7 +4136,7 @@ struct gendisk *__blk_mq_alloc_disk(struct blk_mq_tag_set *set, void *queuedata,
 	struct request_queue *q;
 	struct gendisk *disk;
 
-	q = blk_mq_init_queue_data(set, queuedata);
+	q = blk_mq_alloc_queue(set, NULL, queuedata);
 	if (IS_ERR(q))
 		return ERR_CAST(q);
 
diff --git a/block/bsg-lib.c b/block/bsg-lib.c
index b3acdbdb6e7ea8..bcc7dee6abced6 100644
--- a/block/bsg-lib.c
+++ b/block/bsg-lib.c
@@ -383,7 +383,7 @@ struct request_queue *bsg_setup_queue(struct device *dev, const char *name,
 	if (blk_mq_alloc_tag_set(set))
 		goto out_tag_set;
 
-	q = blk_mq_init_queue(set);
+	q = blk_mq_alloc_queue(set, NULL, NULL);
 	if (IS_ERR(q)) {
 		ret = PTR_ERR(q);
 		goto out_queue;
diff --git a/drivers/nvme/host/apple.c b/drivers/nvme/host/apple.c
index c727cd1f264bf6..a480cdeac2883c 100644
--- a/drivers/nvme/host/apple.c
+++ b/drivers/nvme/host/apple.c
@@ -1516,7 +1516,7 @@ static int apple_nvme_probe(struct platform_device *pdev)
 		goto put_dev;
 	}
 
-	anv->ctrl.admin_q = blk_mq_init_queue(&anv->admin_tagset);
+	anv->ctrl.admin_q = blk_mq_alloc_queue(&anv->admin_tagset, NULL, NULL);
 	if (IS_ERR(anv->ctrl.admin_q)) {
 		ret = -ENOMEM;
 		goto put_dev;
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 6e7f9b13fba2d3..5bcdf3654598e4 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -4372,14 +4372,14 @@ int nvme_alloc_admin_tag_set(struct nvme_ctrl *ctrl, struct blk_mq_tag_set *set,
 	if (ret)
 		return ret;
 
-	ctrl->admin_q = blk_mq_init_queue(set);
+	ctrl->admin_q = blk_mq_alloc_queue(set, NULL, NULL);
 	if (IS_ERR(ctrl->admin_q)) {
 		ret = PTR_ERR(ctrl->admin_q);
 		goto out_free_tagset;
 	}
 
 	if (ctrl->ops->flags & NVME_F_FABRICS) {
-		ctrl->fabrics_q = blk_mq_init_queue(set);
+		ctrl->fabrics_q = blk_mq_alloc_queue(set, NULL, NULL);
 		if (IS_ERR(ctrl->fabrics_q)) {
 			ret = PTR_ERR(ctrl->fabrics_q);
 			goto out_cleanup_admin_q;
@@ -4443,7 +4443,7 @@ int nvme_alloc_io_tag_set(struct nvme_ctrl *ctrl, struct blk_mq_tag_set *set,
 		return ret;
 
 	if (ctrl->ops->flags & NVME_F_FABRICS) {
-		ctrl->connect_q = blk_mq_init_queue(set);
+		ctrl->connect_q = blk_mq_alloc_queue(set, NULL, NULL);
         	if (IS_ERR(ctrl->connect_q)) {
 			ret = PTR_ERR(ctrl->connect_q);
 			goto out_free_tag_set;
diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
index 44680f65ea1455..9969f4e2f1c3d9 100644
--- a/drivers/scsi/scsi_scan.c
+++ b/drivers/scsi/scsi_scan.c
@@ -332,7 +332,7 @@ static struct scsi_device *scsi_alloc_sdev(struct scsi_target *starget,
 
 	sdev->sg_reserved_size = INT_MAX;
 
-	q = blk_mq_init_queue(&sdev->host->tag_set);
+	q = blk_mq_alloc_queue(&sdev->host->tag_set, NULL, NULL);
 	if (IS_ERR(q)) {
 		/* release fn is set up in scsi_sysfs_device_initialise, so
 		 * have to free and put manually here */
diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
index 029d017fc1b66b..c502a86db16b30 100644
--- a/drivers/ufs/core/ufshcd.c
+++ b/drivers/ufs/core/ufshcd.c
@@ -10592,7 +10592,7 @@ int ufshcd_init(struct ufs_hba *hba, void __iomem *mmio_base, unsigned int irq)
 	err = blk_mq_alloc_tag_set(&hba->tmf_tag_set);
 	if (err < 0)
 		goto out_remove_scsi_host;
-	hba->tmf_queue = blk_mq_init_queue(&hba->tmf_tag_set);
+	hba->tmf_queue = blk_mq_alloc_queue(&hba->tmf_tag_set, NULL, NULL);
 	if (IS_ERR(hba->tmf_queue)) {
 		err = PTR_ERR(hba->tmf_queue);
 		goto free_tmf_tag_set;
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 7a8150a5f05133..7d42c359e2ab28 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -692,7 +692,8 @@ struct gendisk *__blk_mq_alloc_disk(struct blk_mq_tag_set *set, void *queuedata,
 })
 struct gendisk *blk_mq_alloc_disk_for_queue(struct request_queue *q,
 		struct lock_class_key *lkclass);
-struct request_queue *blk_mq_init_queue(struct blk_mq_tag_set *);
+struct request_queue *blk_mq_alloc_queue(struct blk_mq_tag_set *set,
+		struct queue_limits *lim, void *queuedata);
 int blk_mq_init_allocated_queue(struct blk_mq_tag_set *set,
 		struct request_queue *q);
 void blk_mq_destroy_queue(struct request_queue *);
-- 
2.39.2

[PATCH 10/15] block: pass a queue_limits argument to blk_mq_alloc_disk

[Christoph Hellwig]

Pass a queue_limits to blk_mq_alloc_disk and apply it if non-NULL.  This
will allow allocating queues with valid queue limits instead of setting
the values one at a time later.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
---
 arch/um/drivers/ubd_kern.c          | 2 +-
 block/blk-mq.c                      | 5 +++--
 drivers/block/amiflop.c             | 2 +-
 drivers/block/aoe/aoeblk.c          | 2 +-
 drivers/block/ataflop.c             | 2 +-
 drivers/block/floppy.c              | 2 +-
 drivers/block/loop.c                | 2 +-
 drivers/block/mtip32xx/mtip32xx.c   | 2 +-
 drivers/block/nbd.c                 | 2 +-
 drivers/block/null_blk/main.c       | 2 +-
 drivers/block/ps3disk.c             | 2 +-
 drivers/block/rbd.c                 | 2 +-
 drivers/block/rnbd/rnbd-clt.c       | 2 +-
 drivers/block/sunvdc.c              | 2 +-
 drivers/block/swim.c                | 2 +-
 drivers/block/swim3.c               | 2 +-
 drivers/block/ublk_drv.c            | 2 +-
 drivers/block/virtio_blk.c          | 2 +-
 drivers/block/xen-blkfront.c        | 2 +-
 drivers/block/z2ram.c               | 2 +-
 drivers/cdrom/gdrom.c               | 2 +-
 drivers/memstick/core/ms_block.c    | 2 +-
 drivers/memstick/core/mspro_block.c | 2 +-
 drivers/mmc/core/queue.c            | 2 +-
 drivers/mtd/mtd_blkdevs.c           | 2 +-
 drivers/mtd/ubi/block.c             | 2 +-
 drivers/nvme/host/core.c            | 2 +-
 drivers/s390/block/dasd_genhd.c     | 2 +-
 drivers/s390/block/scm_blk.c        | 2 +-
 include/linux/blk-mq.h              | 7 ++++---
 30 files changed, 35 insertions(+), 33 deletions(-)

diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c
index 92ee2697ff3984..25f1b18ce7d4e9 100644
--- a/arch/um/drivers/ubd_kern.c
+++ b/arch/um/drivers/ubd_kern.c
@@ -906,7 +906,7 @@ static int ubd_add(int n, char **error_out)
 	if (err)
 		goto out;
 
-	disk = blk_mq_alloc_disk(&ubd_dev->tag_set, ubd_dev);
+	disk = blk_mq_alloc_disk(&ubd_dev->tag_set, NULL, ubd_dev);
 	if (IS_ERR(disk)) {
 		err = PTR_ERR(disk);
 		goto out_cleanup_tags;
diff --git a/block/blk-mq.c b/block/blk-mq.c
index f6499bbd89be90..6abb4ce46baa1e 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -4130,13 +4130,14 @@ void blk_mq_destroy_queue(struct request_queue *q)
 }
 EXPORT_SYMBOL(blk_mq_destroy_queue);
 
-struct gendisk *__blk_mq_alloc_disk(struct blk_mq_tag_set *set, void *queuedata,
+struct gendisk *__blk_mq_alloc_disk(struct blk_mq_tag_set *set,
+		struct queue_limits *lim, void *queuedata,
 		struct lock_class_key *lkclass)
 {
 	struct request_queue *q;
 	struct gendisk *disk;
 
-	q = blk_mq_alloc_queue(set, NULL, queuedata);
+	q = blk_mq_alloc_queue(set, lim, queuedata);
 	if (IS_ERR(q))
 		return ERR_CAST(q);
 
diff --git a/drivers/block/amiflop.c b/drivers/block/amiflop.c
index 2b98114a9fe092..a25414228e4741 100644
--- a/drivers/block/amiflop.c
+++ b/drivers/block/amiflop.c
@@ -1779,7 +1779,7 @@ static int fd_alloc_disk(int drive, int system)
 	struct gendisk *disk;
 	int err;
 
-	disk = blk_mq_alloc_disk(&unit[drive].tag_set, NULL);
+	disk = blk_mq_alloc_disk(&unit[drive].tag_set, NULL, NULL);
 	if (IS_ERR(disk))
 		return PTR_ERR(disk);
 
diff --git a/drivers/block/aoe/aoeblk.c b/drivers/block/aoe/aoeblk.c
index b1b47d88f5db44..2ff6e2da8cc41c 100644
--- a/drivers/block/aoe/aoeblk.c
+++ b/drivers/block/aoe/aoeblk.c
@@ -371,7 +371,7 @@ aoeblk_gdalloc(void *vp)
 		goto err_mempool;
 	}
 
-	gd = blk_mq_alloc_disk(set, d);
+	gd = blk_mq_alloc_disk(set, NULL, d);
 	if (IS_ERR(gd)) {
 		pr_err("aoe: cannot allocate block queue for %ld.%d\n",
 			d->aoemajor, d->aoeminor);
diff --git a/drivers/block/ataflop.c b/drivers/block/ataflop.c
index 50949207798d2a..cacc4ba942a814 100644
--- a/drivers/block/ataflop.c
+++ b/drivers/block/ataflop.c
@@ -1994,7 +1994,7 @@ static int ataflop_alloc_disk(unsigned int drive, unsigned int type)
 {
 	struct gendisk *disk;
 
-	disk = blk_mq_alloc_disk(&unit[drive].tag_set, NULL);
+	disk = blk_mq_alloc_disk(&unit[drive].tag_set, NULL, NULL);
 	if (IS_ERR(disk))
 		return PTR_ERR(disk);
 
diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c
index d0e41d52d6a9b5..6f765d221b3814 100644
--- a/drivers/block/floppy.c
+++ b/drivers/block/floppy.c
@@ -4515,7 +4515,7 @@ static int floppy_alloc_disk(unsigned int drive, unsigned int type)
 {
 	struct gendisk *disk;
 
-	disk = blk_mq_alloc_disk(&tag_sets[drive], NULL);
+	disk = blk_mq_alloc_disk(&tag_sets[drive], NULL, NULL);
 	if (IS_ERR(disk))
 		return PTR_ERR(disk);
 
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index f8145499da38c8..3f855cc79c29f5 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -2025,7 +2025,7 @@ static int loop_add(int i)
 	if (err)
 		goto out_free_idr;
 
-	disk = lo->lo_disk = blk_mq_alloc_disk(&lo->tag_set, lo);
+	disk = lo->lo_disk = blk_mq_alloc_disk(&lo->tag_set, NULL, lo);
 	if (IS_ERR(disk)) {
 		err = PTR_ERR(disk);
 		goto out_cleanup_tags;
diff --git a/drivers/block/mtip32xx/mtip32xx.c b/drivers/block/mtip32xx/mtip32xx.c
index b200950e8fb5f9..ac08dea73552f4 100644
--- a/drivers/block/mtip32xx/mtip32xx.c
+++ b/drivers/block/mtip32xx/mtip32xx.c
@@ -3431,7 +3431,7 @@ static int mtip_block_initialize(struct driver_data *dd)
 		goto block_queue_alloc_tag_error;
 	}
 
-	dd->disk = blk_mq_alloc_disk(&dd->tags, dd);
+	dd->disk = blk_mq_alloc_disk(&dd->tags, NULL, dd);
 	if (IS_ERR(dd->disk)) {
 		dev_err(&dd->pdev->dev,
 			"Unable to allocate request queue\n");
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 33a8f37bb6a1f5..30ae3cc12e7787 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -1823,7 +1823,7 @@ static struct nbd_device *nbd_dev_add(int index, unsigned int refs)
 	if (err < 0)
 		goto out_free_tags;
 
-	disk = blk_mq_alloc_disk(&nbd->tag_set, NULL);
+	disk = blk_mq_alloc_disk(&nbd->tag_set, NULL, NULL);
 	if (IS_ERR(disk)) {
 		err = PTR_ERR(disk);
 		goto out_free_idr;
diff --git a/drivers/block/null_blk/main.c b/drivers/block/null_blk/main.c
index 4281371c81fed1..eeb895ec6f34ae 100644
--- a/drivers/block/null_blk/main.c
+++ b/drivers/block/null_blk/main.c
@@ -2147,7 +2147,7 @@ static int null_add_dev(struct nullb_device *dev)
 			goto out_cleanup_queues;
 
 		nullb->tag_set->timeout = 5 * HZ;
-		nullb->disk = blk_mq_alloc_disk(nullb->tag_set, nullb);
+		nullb->disk = blk_mq_alloc_disk(nullb->tag_set, NULL, nullb);
 		if (IS_ERR(nullb->disk)) {
 			rv = PTR_ERR(nullb->disk);
 			goto out_cleanup_tags;
diff --git a/drivers/block/ps3disk.c b/drivers/block/ps3disk.c
index 36d7b36c60c76b..dfd3860df4f880 100644
--- a/drivers/block/ps3disk.c
+++ b/drivers/block/ps3disk.c
@@ -431,7 +431,7 @@ static int ps3disk_probe(struct ps3_system_bus_device *_dev)
 	if (error)
 		goto fail_teardown;
 
-	gendisk = blk_mq_alloc_disk(&priv->tag_set, dev);
+	gendisk = blk_mq_alloc_disk(&priv->tag_set, NULL, dev);
 	if (IS_ERR(gendisk)) {
 		dev_err(&dev->sbd.core, "%s:%u: blk_mq_alloc_disk failed\n",
 			__func__, __LINE__);
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 00ca8a1d8c46ff..6b4f1898a722a3 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -4966,7 +4966,7 @@ static int rbd_init_disk(struct rbd_device *rbd_dev)
 	if (err)
 		return err;
 
-	disk = blk_mq_alloc_disk(&rbd_dev->tag_set, rbd_dev);
+	disk = blk_mq_alloc_disk(&rbd_dev->tag_set, NULL, rbd_dev);
 	if (IS_ERR(disk)) {
 		err = PTR_ERR(disk);
 		goto out_tag_set;
diff --git a/drivers/block/rnbd/rnbd-clt.c b/drivers/block/rnbd/rnbd-clt.c
index 4044c369d22a5f..d51be4f2df61a3 100644
--- a/drivers/block/rnbd/rnbd-clt.c
+++ b/drivers/block/rnbd/rnbd-clt.c
@@ -1408,7 +1408,7 @@ static int rnbd_client_setup_device(struct rnbd_clt_dev *dev,
 	dev->size = le64_to_cpu(rsp->nsectors) *
 			le16_to_cpu(rsp->logical_block_size);
 
-	dev->gd = blk_mq_alloc_disk(&dev->sess->tag_set, dev);
+	dev->gd = blk_mq_alloc_disk(&dev->sess->tag_set, NULL, dev);
 	if (IS_ERR(dev->gd))
 		return PTR_ERR(dev->gd);
 	dev->queue = dev->gd->queue;
diff --git a/drivers/block/sunvdc.c b/drivers/block/sunvdc.c
index 7bf4b48e2282e7..a1f74dd1eae5d5 100644
--- a/drivers/block/sunvdc.c
+++ b/drivers/block/sunvdc.c
@@ -824,7 +824,7 @@ static int probe_disk(struct vdc_port *port)
 	if (err)
 		return err;
 
-	g = blk_mq_alloc_disk(&port->tag_set, port);
+	g = blk_mq_alloc_disk(&port->tag_set, NULL, port);
 	if (IS_ERR(g)) {
 		printk(KERN_ERR PFX "%s: Could not allocate gendisk.\n",
 		       port->vio.name);
diff --git a/drivers/block/swim.c b/drivers/block/swim.c
index f85b6af414b431..16bdf62067d8b1 100644
--- a/drivers/block/swim.c
+++ b/drivers/block/swim.c
@@ -820,7 +820,7 @@ static int swim_floppy_init(struct swim_priv *swd)
 			goto exit_put_disks;
 
 		swd->unit[drive].disk =
-			blk_mq_alloc_disk(&swd->unit[drive].tag_set,
+			blk_mq_alloc_disk(&swd->unit[drive].tag_set, NULL,
 					  &swd->unit[drive]);
 		if (IS_ERR(swd->unit[drive].disk)) {
 			blk_mq_free_tag_set(&swd->unit[drive].tag_set);
diff --git a/drivers/block/swim3.c b/drivers/block/swim3.c
index c2bc85826358e9..a04756ac778ee8 100644
--- a/drivers/block/swim3.c
+++ b/drivers/block/swim3.c
@@ -1210,7 +1210,7 @@ static int swim3_attach(struct macio_dev *mdev,
 	if (rc)
 		goto out_unregister;
 
-	disk = blk_mq_alloc_disk(&fs->tag_set, fs);
+	disk = blk_mq_alloc_disk(&fs->tag_set, NULL, fs);
 	if (IS_ERR(disk)) {
 		rc = PTR_ERR(disk);
 		goto out_free_tag_set;
diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
index 1dfb2e77898ba6..c5b6552707984b 100644
--- a/drivers/block/ublk_drv.c
+++ b/drivers/block/ublk_drv.c
@@ -2222,7 +2222,7 @@ static int ublk_ctrl_start_dev(struct ublk_device *ub, struct io_uring_cmd *cmd)
 		goto out_unlock;
 	}
 
-	disk = blk_mq_alloc_disk(&ub->tag_set, NULL);
+	disk = blk_mq_alloc_disk(&ub->tag_set, NULL, NULL);
 	if (IS_ERR(disk)) {
 		ret = PTR_ERR(disk);
 		goto out_unlock;
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index 5bf98fd6a651a5..a23fce4eca4408 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -1330,7 +1330,7 @@ static int virtblk_probe(struct virtio_device *vdev)
 	if (err)
 		goto out_free_vq;
 
-	vblk->disk = blk_mq_alloc_disk(&vblk->tag_set, vblk);
+	vblk->disk = blk_mq_alloc_disk(&vblk->tag_set, NULL, vblk);
 	if (IS_ERR(vblk->disk)) {
 		err = PTR_ERR(vblk->disk);
 		goto out_free_tags;
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 434fab30677743..4cc2884e748463 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -1136,7 +1136,7 @@ static int xlvbd_alloc_gendisk(blkif_sector_t capacity,
 	if (err)
 		goto out_release_minors;
 
-	gd = blk_mq_alloc_disk(&info->tag_set, info);
+	gd = blk_mq_alloc_disk(&info->tag_set, NULL, info);
 	if (IS_ERR(gd)) {
 		err = PTR_ERR(gd);
 		goto out_free_tag_set;
diff --git a/drivers/block/z2ram.c b/drivers/block/z2ram.c
index 11493167b0a848..7c5f4e4d9b5037 100644
--- a/drivers/block/z2ram.c
+++ b/drivers/block/z2ram.c
@@ -318,7 +318,7 @@ static int z2ram_register_disk(int minor)
 	struct gendisk *disk;
 	int err;
 
-	disk = blk_mq_alloc_disk(&tag_set, NULL);
+	disk = blk_mq_alloc_disk(&tag_set, NULL, NULL);
 	if (IS_ERR(disk))
 		return PTR_ERR(disk);
 
diff --git a/drivers/cdrom/gdrom.c b/drivers/cdrom/gdrom.c
index d668b174ace92f..1d044779f5e42a 100644
--- a/drivers/cdrom/gdrom.c
+++ b/drivers/cdrom/gdrom.c
@@ -778,7 +778,7 @@ static int probe_gdrom(struct platform_device *devptr)
 	if (err)
 		goto probe_fail_free_cd_info;
 
-	gd.disk = blk_mq_alloc_disk(&gd.tag_set, NULL);
+	gd.disk = blk_mq_alloc_disk(&gd.tag_set, NULL, NULL);
 	if (IS_ERR(gd.disk)) {
 		err = PTR_ERR(gd.disk);
 		goto probe_fail_free_tag_set;
diff --git a/drivers/memstick/core/ms_block.c b/drivers/memstick/core/ms_block.c
index 04115cd92433bf..d3277c901d16bb 100644
--- a/drivers/memstick/core/ms_block.c
+++ b/drivers/memstick/core/ms_block.c
@@ -2093,7 +2093,7 @@ static int msb_init_disk(struct memstick_dev *card)
 	if (rc)
 		goto out_release_id;
 
-	msb->disk = blk_mq_alloc_disk(&msb->tag_set, card);
+	msb->disk = blk_mq_alloc_disk(&msb->tag_set, NULL, card);
 	if (IS_ERR(msb->disk)) {
 		rc = PTR_ERR(msb->disk);
 		goto out_free_tag_set;
diff --git a/drivers/memstick/core/mspro_block.c b/drivers/memstick/core/mspro_block.c
index 5a69ed33999b4c..db0e2a42ca3c32 100644
--- a/drivers/memstick/core/mspro_block.c
+++ b/drivers/memstick/core/mspro_block.c
@@ -1138,7 +1138,7 @@ static int mspro_block_init_disk(struct memstick_dev *card)
 	if (rc)
 		goto out_release_id;
 
-	msb->disk = blk_mq_alloc_disk(&msb->tag_set, card);
+	msb->disk = blk_mq_alloc_disk(&msb->tag_set, NULL, card);
 	if (IS_ERR(msb->disk)) {
 		rc = PTR_ERR(msb->disk);
 		goto out_free_tag_set;
diff --git a/drivers/mmc/core/queue.c b/drivers/mmc/core/queue.c
index a0a2412f62a730..67ad186d132a69 100644
--- a/drivers/mmc/core/queue.c
+++ b/drivers/mmc/core/queue.c
@@ -447,7 +447,7 @@ struct gendisk *mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card)
 		return ERR_PTR(ret);
 		
 
-	disk = blk_mq_alloc_disk(&mq->tag_set, mq);
+	disk = blk_mq_alloc_disk(&mq->tag_set, NULL, mq);
 	if (IS_ERR(disk)) {
 		blk_mq_free_tag_set(&mq->tag_set);
 		return disk;
diff --git a/drivers/mtd/mtd_blkdevs.c b/drivers/mtd/mtd_blkdevs.c
index f0526dcc216276..b8878a2457afa7 100644
--- a/drivers/mtd/mtd_blkdevs.c
+++ b/drivers/mtd/mtd_blkdevs.c
@@ -333,7 +333,7 @@ int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
 		goto out_kfree_tag_set;
 
 	/* Create gendisk */
-	gd = blk_mq_alloc_disk(new->tag_set, new);
+	gd = blk_mq_alloc_disk(new->tag_set, NULL, new);
 	if (IS_ERR(gd)) {
 		ret = PTR_ERR(gd);
 		goto out_free_tag_set;
diff --git a/drivers/mtd/ubi/block.c b/drivers/mtd/ubi/block.c
index 654bd7372cd8c0..9be87c231a2eba 100644
--- a/drivers/mtd/ubi/block.c
+++ b/drivers/mtd/ubi/block.c
@@ -393,7 +393,7 @@ int ubiblock_create(struct ubi_volume_info *vi)
 
 
 	/* Initialize the gendisk of this ubiblock device */
-	gd = blk_mq_alloc_disk(&dev->tag_set, dev);
+	gd = blk_mq_alloc_disk(&dev->tag_set, NULL, dev);
 	if (IS_ERR(gd)) {
 		ret = PTR_ERR(gd);
 		goto out_free_tags;
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 5bcdf3654598e4..eed3e22e24d913 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -3694,7 +3694,7 @@ static void nvme_alloc_ns(struct nvme_ctrl *ctrl, struct nvme_ns_info *info)
 	if (!ns)
 		return;
 
-	disk = blk_mq_alloc_disk(ctrl->tagset, ns);
+	disk = blk_mq_alloc_disk(ctrl->tagset, NULL, ns);
 	if (IS_ERR(disk))
 		goto out_free_ns;
 	disk->fops = &nvme_bdev_ops;
diff --git a/drivers/s390/block/dasd_genhd.c b/drivers/s390/block/dasd_genhd.c
index 30e8ee583e980e..0465b706745f64 100644
--- a/drivers/s390/block/dasd_genhd.c
+++ b/drivers/s390/block/dasd_genhd.c
@@ -53,7 +53,7 @@ int dasd_gendisk_alloc(struct dasd_block *block)
 	if (rc)
 		return rc;
 
-	gdp = blk_mq_alloc_disk(&block->tag_set, block);
+	gdp = blk_mq_alloc_disk(&block->tag_set, NULL, block);
 	if (IS_ERR(gdp)) {
 		blk_mq_free_tag_set(&block->tag_set);
 		return PTR_ERR(gdp);
diff --git a/drivers/s390/block/scm_blk.c b/drivers/s390/block/scm_blk.c
index ade95e91b3c8db..d05b2e2799a47a 100644
--- a/drivers/s390/block/scm_blk.c
+++ b/drivers/s390/block/scm_blk.c
@@ -462,7 +462,7 @@ int scm_blk_dev_setup(struct scm_blk_dev *bdev, struct scm_device *scmdev)
 	if (ret)
 		goto out;
 
-	bdev->gendisk = blk_mq_alloc_disk(&bdev->tag_set, scmdev);
+	bdev->gendisk = blk_mq_alloc_disk(&bdev->tag_set, NULL, scmdev);
 	if (IS_ERR(bdev->gendisk)) {
 		ret = PTR_ERR(bdev->gendisk);
 		goto out_tag;
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 7d42c359e2ab28..390d35fa003295 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -682,13 +682,14 @@ enum {
 
 #define BLK_MQ_NO_HCTX_IDX	(-1U)
 
-struct gendisk *__blk_mq_alloc_disk(struct blk_mq_tag_set *set, void *queuedata,
+struct gendisk *__blk_mq_alloc_disk(struct blk_mq_tag_set *set,
+		struct queue_limits *lim, void *queuedata,
 		struct lock_class_key *lkclass);
-#define blk_mq_alloc_disk(set, queuedata)				\
+#define blk_mq_alloc_disk(set, lim, queuedata)				\
 ({									\
 	static struct lock_class_key __key;				\
 									\
-	__blk_mq_alloc_disk(set, queuedata, &__key);			\
+	__blk_mq_alloc_disk(set, lim, queuedata, &__key);		\
 })
 struct gendisk *blk_mq_alloc_disk_for_queue(struct request_queue *q,
 		struct lock_class_key *lkclass);
-- 
2.39.2

[PATCH 11/15] virtio_blk: split virtblk_probe

[Christoph Hellwig]

Split out a virtblk_read_limits helper that just reads the various
queue limits to separate it from the higher level probing logic.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
---
 drivers/block/virtio_blk.c | 193 +++++++++++++++++++------------------
 1 file changed, 101 insertions(+), 92 deletions(-)

diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index a23fce4eca4408..dd46ccd9f84c7d 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -1248,31 +1248,17 @@ static const struct blk_mq_ops virtio_mq_ops = {
 static unsigned int virtblk_queue_depth;
 module_param_named(queue_depth, virtblk_queue_depth, uint, 0444);
 
-static int virtblk_probe(struct virtio_device *vdev)
+static int virtblk_read_limits(struct virtio_blk *vblk)
 {
-	struct virtio_blk *vblk;
-	struct request_queue *q;
-	int err, index;
-
+	struct request_queue *q = vblk->disk->queue;
+	struct virtio_device *vdev = vblk->vdev;
 	u32 v, blk_size, max_size, sg_elems, opt_io_size;
 	u32 max_discard_segs = 0;
 	u32 discard_granularity = 0;
 	u16 min_io_size;
 	u8 physical_block_exp, alignment_offset;
-	unsigned int queue_depth;
 	size_t max_dma_size;
-
-	if (!vdev->config->get) {
-		dev_err(&vdev->dev, "%s failure: config access disabled\n",
-			__func__);
-		return -EINVAL;
-	}
-
-	err = ida_alloc_range(&vd_index_ida, 0,
-			      minor_to_index(1 << MINORBITS) - 1, GFP_KERNEL);
-	if (err < 0)
-		goto out;
-	index = err;
+	int err;
 
 	/* We need to know how many segments before we allocate. */
 	err = virtio_cread_feature(vdev, VIRTIO_BLK_F_SEG_MAX,
@@ -1286,73 +1272,6 @@ static int virtblk_probe(struct virtio_device *vdev)
 	/* Prevent integer overflows and honor max vq size */
 	sg_elems = min_t(u32, sg_elems, VIRTIO_BLK_MAX_SG_ELEMS - 2);
 
-	vdev->priv = vblk = kmalloc(sizeof(*vblk), GFP_KERNEL);
-	if (!vblk) {
-		err = -ENOMEM;
-		goto out_free_index;
-	}
-
-	mutex_init(&vblk->vdev_mutex);
-
-	vblk->vdev = vdev;
-
-	INIT_WORK(&vblk->config_work, virtblk_config_changed_work);
-
-	err = init_vq(vblk);
-	if (err)
-		goto out_free_vblk;
-
-	/* Default queue sizing is to fill the ring. */
-	if (!virtblk_queue_depth) {
-		queue_depth = vblk->vqs[0].vq->num_free;
-		/* ... but without indirect descs, we use 2 descs per req */
-		if (!virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC))
-			queue_depth /= 2;
-	} else {
-		queue_depth = virtblk_queue_depth;
-	}
-
-	memset(&vblk->tag_set, 0, sizeof(vblk->tag_set));
-	vblk->tag_set.ops = &virtio_mq_ops;
-	vblk->tag_set.queue_depth = queue_depth;
-	vblk->tag_set.numa_node = NUMA_NO_NODE;
-	vblk->tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
-	vblk->tag_set.cmd_size =
-		sizeof(struct virtblk_req) +
-		sizeof(struct scatterlist) * VIRTIO_BLK_INLINE_SG_CNT;
-	vblk->tag_set.driver_data = vblk;
-	vblk->tag_set.nr_hw_queues = vblk->num_vqs;
-	vblk->tag_set.nr_maps = 1;
-	if (vblk->io_queues[HCTX_TYPE_POLL])
-		vblk->tag_set.nr_maps = 3;
-
-	err = blk_mq_alloc_tag_set(&vblk->tag_set);
-	if (err)
-		goto out_free_vq;
-
-	vblk->disk = blk_mq_alloc_disk(&vblk->tag_set, NULL, vblk);
-	if (IS_ERR(vblk->disk)) {
-		err = PTR_ERR(vblk->disk);
-		goto out_free_tags;
-	}
-	q = vblk->disk->queue;
-
-	virtblk_name_format("vd", index, vblk->disk->disk_name, DISK_NAME_LEN);
-
-	vblk->disk->major = major;
-	vblk->disk->first_minor = index_to_minor(index);
-	vblk->disk->minors = 1 << PART_BITS;
-	vblk->disk->private_data = vblk;
-	vblk->disk->fops = &virtblk_fops;
-	vblk->index = index;
-
-	/* configure queue flush support */
-	virtblk_update_cache_mode(vdev);
-
-	/* If disk is read-only in the host, the guest should obey */
-	if (virtio_has_feature(vdev, VIRTIO_BLK_F_RO))
-		set_disk_ro(vblk->disk, 1);
-
 	/* We can handle whatever the host told us to handle. */
 	blk_queue_max_segments(q, sg_elems);
 
@@ -1381,7 +1300,7 @@ static int virtblk_probe(struct virtio_device *vdev)
 			dev_err(&vdev->dev,
 				"virtio_blk: invalid block size: 0x%x\n",
 				blk_size);
-			goto out_cleanup_disk;
+			return err;
 		}
 
 		blk_queue_logical_block_size(q, blk_size);
@@ -1455,8 +1374,7 @@ static int virtblk_probe(struct virtio_device *vdev)
 		if (!v) {
 			dev_err(&vdev->dev,
 				"virtio_blk: secure_erase_sector_alignment can't be 0\n");
-			err = -EINVAL;
-			goto out_cleanup_disk;
+			return -EINVAL;
 		}
 
 		discard_granularity = min_not_zero(discard_granularity, v);
@@ -1470,8 +1388,7 @@ static int virtblk_probe(struct virtio_device *vdev)
 		if (!v) {
 			dev_err(&vdev->dev,
 				"virtio_blk: max_secure_erase_sectors can't be 0\n");
-			err = -EINVAL;
-			goto out_cleanup_disk;
+			return -EINVAL;
 		}
 
 		blk_queue_max_secure_erase_sectors(q, v);
@@ -1485,8 +1402,7 @@ static int virtblk_probe(struct virtio_device *vdev)
 		if (!v) {
 			dev_err(&vdev->dev,
 				"virtio_blk: max_secure_erase_seg can't be 0\n");
-			err = -EINVAL;
-			goto out_cleanup_disk;
+			return -EINVAL;
 		}
 
 		max_discard_segs = min_not_zero(max_discard_segs, v);
@@ -1511,6 +1427,99 @@ static int virtblk_probe(struct virtio_device *vdev)
 			q->limits.discard_granularity = blk_size;
 	}
 
+	return 0;
+}
+
+static int virtblk_probe(struct virtio_device *vdev)
+{
+	struct virtio_blk *vblk;
+	struct request_queue *q;
+	int err, index;
+	unsigned int queue_depth;
+
+	if (!vdev->config->get) {
+		dev_err(&vdev->dev, "%s failure: config access disabled\n",
+			__func__);
+		return -EINVAL;
+	}
+
+	err = ida_alloc_range(&vd_index_ida, 0,
+			      minor_to_index(1 << MINORBITS) - 1, GFP_KERNEL);
+	if (err < 0)
+		goto out;
+	index = err;
+
+	vdev->priv = vblk = kmalloc(sizeof(*vblk), GFP_KERNEL);
+	if (!vblk) {
+		err = -ENOMEM;
+		goto out_free_index;
+	}
+
+	mutex_init(&vblk->vdev_mutex);
+
+	vblk->vdev = vdev;
+
+	INIT_WORK(&vblk->config_work, virtblk_config_changed_work);
+
+	err = init_vq(vblk);
+	if (err)
+		goto out_free_vblk;
+
+	/* Default queue sizing is to fill the ring. */
+	if (!virtblk_queue_depth) {
+		queue_depth = vblk->vqs[0].vq->num_free;
+		/* ... but without indirect descs, we use 2 descs per req */
+		if (!virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC))
+			queue_depth /= 2;
+	} else {
+		queue_depth = virtblk_queue_depth;
+	}
+
+	memset(&vblk->tag_set, 0, sizeof(vblk->tag_set));
+	vblk->tag_set.ops = &virtio_mq_ops;
+	vblk->tag_set.queue_depth = queue_depth;
+	vblk->tag_set.numa_node = NUMA_NO_NODE;
+	vblk->tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
+	vblk->tag_set.cmd_size =
+		sizeof(struct virtblk_req) +
+		sizeof(struct scatterlist) * VIRTIO_BLK_INLINE_SG_CNT;
+	vblk->tag_set.driver_data = vblk;
+	vblk->tag_set.nr_hw_queues = vblk->num_vqs;
+	vblk->tag_set.nr_maps = 1;
+	if (vblk->io_queues[HCTX_TYPE_POLL])
+		vblk->tag_set.nr_maps = 3;
+
+	err = blk_mq_alloc_tag_set(&vblk->tag_set);
+	if (err)
+		goto out_free_vq;
+
+	vblk->disk = blk_mq_alloc_disk(&vblk->tag_set, NULL, vblk);
+	if (IS_ERR(vblk->disk)) {
+		err = PTR_ERR(vblk->disk);
+		goto out_free_tags;
+	}
+	q = vblk->disk->queue;
+
+	virtblk_name_format("vd", index, vblk->disk->disk_name, DISK_NAME_LEN);
+
+	vblk->disk->major = major;
+	vblk->disk->first_minor = index_to_minor(index);
+	vblk->disk->minors = 1 << PART_BITS;
+	vblk->disk->private_data = vblk;
+	vblk->disk->fops = &virtblk_fops;
+	vblk->index = index;
+
+	/* configure queue flush support */
+	virtblk_update_cache_mode(vdev);
+
+	/* If disk is read-only in the host, the guest should obey */
+	if (virtio_has_feature(vdev, VIRTIO_BLK_F_RO))
+		set_disk_ro(vblk->disk, 1);
+
+	err = virtblk_read_limits(vblk);
+	if (err)
+		goto out_cleanup_disk;
+
 	virtblk_update_capacity(vblk, false);
 	virtio_device_ready(vdev);
 
-- 
2.39.2

[PATCH 12/15] virtio_blk: pass queue_limits to blk_mq_alloc_disk

[Christoph Hellwig]

Call virtblk_read_limits and most of virtblk_probe_zoned_device before
allocating the gendisk and thus request_queue and make them read into
a queue_limits structure instead.  Pass this initialized queue_limits
to blk_mq_alloc_disk to set the queue up with the right parameters
from the start and only leave a few final touches for zoned devices
to be done just before adding the disk.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
---
 drivers/block/virtio_blk.c | 130 ++++++++++++++++++-------------------
 1 file changed, 64 insertions(+), 66 deletions(-)

diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index dd46ccd9f84c7d..d8b55874cd5950 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -720,16 +720,15 @@ static int virtblk_report_zones(struct gendisk *disk, sector_t sector,
 	return ret;
 }
 
-static int virtblk_probe_zoned_device(struct virtio_device *vdev,
-				       struct virtio_blk *vblk,
-				       struct request_queue *q)
+static int virtblk_read_zoned_limits(struct virtio_blk *vblk,
+		struct queue_limits *lim)
 {
+	struct virtio_device *vdev = vblk->vdev;
 	u32 v, wg;
 
 	dev_dbg(&vdev->dev, "probing host-managed zoned device\n");
 
-	disk_set_zoned(vblk->disk);
-	blk_queue_flag_set(QUEUE_FLAG_ZONE_RESETALL, q);
+	lim->zoned = true;
 
 	virtio_cread(vdev, struct virtio_blk_config,
 		     zoned.max_open_zones, &v);
@@ -747,8 +746,8 @@ static int virtblk_probe_zoned_device(struct virtio_device *vdev,
 		dev_warn(&vdev->dev, "zero write granularity reported\n");
 		return -ENODEV;
 	}
-	blk_queue_physical_block_size(q, wg);
-	blk_queue_io_min(q, wg);
+	lim->physical_block_size = wg;
+	lim->io_min = wg;
 
 	dev_dbg(&vdev->dev, "write granularity = %u\n", wg);
 
@@ -764,13 +763,13 @@ static int virtblk_probe_zoned_device(struct virtio_device *vdev,
 			vblk->zone_sectors);
 		return -ENODEV;
 	}
-	blk_queue_chunk_sectors(q, vblk->zone_sectors);
+	lim->chunk_sectors = vblk->zone_sectors;
 	dev_dbg(&vdev->dev, "zone sectors = %u\n", vblk->zone_sectors);
 
 	if (virtio_has_feature(vdev, VIRTIO_BLK_F_DISCARD)) {
 		dev_warn(&vblk->vdev->dev,
 			 "ignoring negotiated F_DISCARD for zoned device\n");
-		blk_queue_max_discard_sectors(q, 0);
+		lim->max_hw_discard_sectors = 0;
 	}
 
 	virtio_cread(vdev, struct virtio_blk_config,
@@ -785,25 +784,21 @@ static int virtblk_probe_zoned_device(struct virtio_device *vdev,
 			wg, v);
 		return -ENODEV;
 	}
-	blk_queue_max_zone_append_sectors(q, v);
+	lim->max_zone_append_sectors = v;
 	dev_dbg(&vdev->dev, "max append sectors = %u\n", v);
 
-	return blk_revalidate_disk_zones(vblk->disk, NULL);
+	return 0;
 }
-
 #else
-
 /*
- * Zoned block device support is not configured in this kernel.
- * Host-managed zoned devices can't be supported, but others are
- * good to go as regular block devices.
+ * Zoned block device support is not configured in this kernel, host-managed
+ * zoned devices can't be supported.
  */
 #define virtblk_report_zones       NULL
-
-static inline int virtblk_probe_zoned_device(struct virtio_device *vdev,
-			struct virtio_blk *vblk, struct request_queue *q)
+static inline int virtblk_read_zoned_limits(struct virtio_blk *vblk,
+		struct queue_limits *lim)
 {
-	dev_err(&vdev->dev,
+	dev_err(&vblk->vdev->dev,
 		"virtio_blk: zoned devices are not supported");
 	return -EOPNOTSUPP;
 }
@@ -1248,9 +1243,9 @@ static const struct blk_mq_ops virtio_mq_ops = {
 static unsigned int virtblk_queue_depth;
 module_param_named(queue_depth, virtblk_queue_depth, uint, 0444);
 
-static int virtblk_read_limits(struct virtio_blk *vblk)
+static int virtblk_read_limits(struct virtio_blk *vblk,
+		struct queue_limits *lim)
 {
-	struct request_queue *q = vblk->disk->queue;
 	struct virtio_device *vdev = vblk->vdev;
 	u32 v, blk_size, max_size, sg_elems, opt_io_size;
 	u32 max_discard_segs = 0;
@@ -1273,10 +1268,10 @@ static int virtblk_read_limits(struct virtio_blk *vblk)
 	sg_elems = min_t(u32, sg_elems, VIRTIO_BLK_MAX_SG_ELEMS - 2);
 
 	/* We can handle whatever the host told us to handle. */
-	blk_queue_max_segments(q, sg_elems);
+	lim->max_segments = sg_elems;
 
 	/* No real sector limit. */
-	blk_queue_max_hw_sectors(q, UINT_MAX);
+	lim->max_hw_sectors = UINT_MAX;
 
 	max_dma_size = virtio_max_dma_size(vdev);
 	max_size = max_dma_size > U32_MAX ? U32_MAX : max_dma_size;
@@ -1288,7 +1283,7 @@ static int virtblk_read_limits(struct virtio_blk *vblk)
 	if (!err)
 		max_size = min(max_size, v);
 
-	blk_queue_max_segment_size(q, max_size);
+	lim->max_segment_size = max_size;
 
 	/* Host can optionally specify the block size of the device */
 	err = virtio_cread_feature(vdev, VIRTIO_BLK_F_BLK_SIZE,
@@ -1303,35 +1298,34 @@ static int virtblk_read_limits(struct virtio_blk *vblk)
 			return err;
 		}
 
-		blk_queue_logical_block_size(q, blk_size);
+		lim->logical_block_size = blk_size;
 	} else
-		blk_size = queue_logical_block_size(q);
+		blk_size = lim->logical_block_size;
 
 	/* Use topology information if available */
 	err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
 				   struct virtio_blk_config, physical_block_exp,
 				   &physical_block_exp);
 	if (!err && physical_block_exp)
-		blk_queue_physical_block_size(q,
-				blk_size * (1 << physical_block_exp));
+		lim->physical_block_size = blk_size * (1 << physical_block_exp);
 
 	err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
 				   struct virtio_blk_config, alignment_offset,
 				   &alignment_offset);
 	if (!err && alignment_offset)
-		blk_queue_alignment_offset(q, blk_size * alignment_offset);
+		lim->alignment_offset = blk_size * alignment_offset;
 
 	err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
 				   struct virtio_blk_config, min_io_size,
 				   &min_io_size);
 	if (!err && min_io_size)
-		blk_queue_io_min(q, blk_size * min_io_size);
+		lim->io_min = blk_size * min_io_size;
 
 	err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY,
 				   struct virtio_blk_config, opt_io_size,
 				   &opt_io_size);
 	if (!err && opt_io_size)
-		blk_queue_io_opt(q, blk_size * opt_io_size);
+		lim->io_opt = blk_size * opt_io_size;
 
 	if (virtio_has_feature(vdev, VIRTIO_BLK_F_DISCARD)) {
 		virtio_cread(vdev, struct virtio_blk_config,
@@ -1339,7 +1333,7 @@ static int virtblk_read_limits(struct virtio_blk *vblk)
 
 		virtio_cread(vdev, struct virtio_blk_config,
 			     max_discard_sectors, &v);
-		blk_queue_max_discard_sectors(q, v ? v : UINT_MAX);
+		lim->max_hw_discard_sectors = v ? v : UINT_MAX;
 
 		virtio_cread(vdev, struct virtio_blk_config, max_discard_seg,
 			     &max_discard_segs);
@@ -1348,7 +1342,7 @@ static int virtblk_read_limits(struct virtio_blk *vblk)
 	if (virtio_has_feature(vdev, VIRTIO_BLK_F_WRITE_ZEROES)) {
 		virtio_cread(vdev, struct virtio_blk_config,
 			     max_write_zeroes_sectors, &v);
-		blk_queue_max_write_zeroes_sectors(q, v ? v : UINT_MAX);
+		lim->max_write_zeroes_sectors = v ? v : UINT_MAX;
 	}
 
 	/* The discard and secure erase limits are combined since the Linux
@@ -1391,7 +1385,7 @@ static int virtblk_read_limits(struct virtio_blk *vblk)
 			return -EINVAL;
 		}
 
-		blk_queue_max_secure_erase_sectors(q, v);
+		lim->max_secure_erase_sectors = v;
 
 		virtio_cread(vdev, struct virtio_blk_config,
 			     max_secure_erase_seg, &v);
@@ -1418,13 +1412,34 @@ static int virtblk_read_limits(struct virtio_blk *vblk)
 		if (!max_discard_segs)
 			max_discard_segs = sg_elems;
 
-		blk_queue_max_discard_segments(q,
-					       min(max_discard_segs, MAX_DISCARD_SEGMENTS));
+		lim->max_discard_segments =
+			min(max_discard_segs, MAX_DISCARD_SEGMENTS);
 
 		if (discard_granularity)
-			q->limits.discard_granularity = discard_granularity << SECTOR_SHIFT;
+			lim->discard_granularity =
+				discard_granularity << SECTOR_SHIFT;
 		else
-			q->limits.discard_granularity = blk_size;
+			lim->discard_granularity = blk_size;
+	}
+
+	if (virtio_has_feature(vdev, VIRTIO_BLK_F_ZONED)) {
+		u8 model;
+
+		virtio_cread(vdev, struct virtio_blk_config, zoned.model, &model);
+		switch (model) {
+		case VIRTIO_BLK_Z_NONE:
+		case VIRTIO_BLK_Z_HA:
+			/* treat host-aware devices as non-zoned */
+			return 0;
+		case VIRTIO_BLK_Z_HM:
+			err = virtblk_read_zoned_limits(vblk, lim);
+			if (err)
+				return err;
+			break;
+		default:
+			dev_err(&vdev->dev, "unsupported zone model %d\n", model);
+			return -EINVAL;
+		}
 	}
 
 	return 0;
@@ -1433,7 +1448,7 @@ static int virtblk_read_limits(struct virtio_blk *vblk)
 static int virtblk_probe(struct virtio_device *vdev)
 {
 	struct virtio_blk *vblk;
-	struct request_queue *q;
+	struct queue_limits lim = { };
 	int err, index;
 	unsigned int queue_depth;
 
@@ -1493,12 +1508,15 @@ static int virtblk_probe(struct virtio_device *vdev)
 	if (err)
 		goto out_free_vq;
 
-	vblk->disk = blk_mq_alloc_disk(&vblk->tag_set, NULL, vblk);
+	err = virtblk_read_limits(vblk, &lim);
+	if (err)
+		goto out_free_tags;
+
+	vblk->disk = blk_mq_alloc_disk(&vblk->tag_set, &lim, vblk);
 	if (IS_ERR(vblk->disk)) {
 		err = PTR_ERR(vblk->disk);
 		goto out_free_tags;
 	}
-	q = vblk->disk->queue;
 
 	virtblk_name_format("vd", index, vblk->disk->disk_name, DISK_NAME_LEN);
 
@@ -1516,10 +1534,6 @@ static int virtblk_probe(struct virtio_device *vdev)
 	if (virtio_has_feature(vdev, VIRTIO_BLK_F_RO))
 		set_disk_ro(vblk->disk, 1);
 
-	err = virtblk_read_limits(vblk);
-	if (err)
-		goto out_cleanup_disk;
-
 	virtblk_update_capacity(vblk, false);
 	virtio_device_ready(vdev);
 
@@ -1527,27 +1541,11 @@ static int virtblk_probe(struct virtio_device *vdev)
 	 * All steps that follow use the VQs therefore they need to be
 	 * placed after the virtio_device_ready() call above.
 	 */
-	if (virtio_has_feature(vdev, VIRTIO_BLK_F_ZONED)) {
-		u8 model;
-
-		virtio_cread(vdev, struct virtio_blk_config, zoned.model,
-				&model);
-		switch (model) {
-		case VIRTIO_BLK_Z_NONE:
-		case VIRTIO_BLK_Z_HA:
-			/* Present the host-aware device as non-zoned */
-			break;
-		case VIRTIO_BLK_Z_HM:
-			err = virtblk_probe_zoned_device(vdev, vblk, q);
-			if (err)
-				goto out_cleanup_disk;
-			break;
-		default:
-			dev_err(&vdev->dev, "unsupported zone model %d\n",
-				model);
-			err = -EINVAL;
+	if (IS_ENABLED(CONFIG_BLK_DEV_ZONED) && lim.zoned) {
+		blk_queue_flag_set(QUEUE_FLAG_ZONE_RESETALL, vblk->disk->queue);
+		err = blk_revalidate_disk_zones(vblk->disk, NULL);
+		if (err)
 			goto out_cleanup_disk;
-		}
 	}
 
 	err = device_add_disk(&vdev->dev, vblk->disk, virtblk_attr_groups);
-- 
2.39.2

[PATCH 13/15] loop: cleanup loop_config_discard

[Christoph Hellwig]

Initialize the local variables for the discard max sectors and
granularity to zero as a sensible default, and then merge the
calls assigning them to the queue limits.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
---
 drivers/block/loop.c | 27 ++++++++-------------------
 1 file changed, 8 insertions(+), 19 deletions(-)

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 3f855cc79c29f5..7abeb586942677 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -755,7 +755,8 @@ static void loop_config_discard(struct loop_device *lo)
 	struct file *file = lo->lo_backing_file;
 	struct inode *inode = file->f_mapping->host;
 	struct request_queue *q = lo->lo_queue;
-	u32 granularity, max_discard_sectors;
+	u32 granularity = 0, max_discard_sectors = 0;
+	struct kstatfs sbuf;
 
 	/*
 	 * If the backing device is a block device, mirror its zeroing
@@ -775,29 +776,17 @@ static void loop_config_discard(struct loop_device *lo)
 	 * We use punch hole to reclaim the free space used by the
 	 * image a.k.a. discard.
 	 */
-	} else if (!file->f_op->fallocate) {
-		max_discard_sectors = 0;
-		granularity = 0;
-
-	} else {
-		struct kstatfs sbuf;
-
+	} else if (file->f_op->fallocate && !vfs_statfs(&file->f_path, &sbuf)) {
 		max_discard_sectors = UINT_MAX >> 9;
-		if (!vfs_statfs(&file->f_path, &sbuf))
-			granularity = sbuf.f_bsize;
-		else
-			max_discard_sectors = 0;
+		granularity = sbuf.f_bsize;
 	}
 
-	if (max_discard_sectors) {
+	blk_queue_max_discard_sectors(q, max_discard_sectors);
+	blk_queue_max_write_zeroes_sectors(q, max_discard_sectors);
+	if (max_discard_sectors)
 		q->limits.discard_granularity = granularity;
-		blk_queue_max_discard_sectors(q, max_discard_sectors);
-		blk_queue_max_write_zeroes_sectors(q, max_discard_sectors);
-	} else {
+	else
 		q->limits.discard_granularity = 0;
-		blk_queue_max_discard_sectors(q, 0);
-		blk_queue_max_write_zeroes_sectors(q, 0);
-	}
 }
 
 struct loop_worker {
-- 
2.39.2

[PATCH 14/15] loop: pass queue_limits to blk_mq_alloc_disk

[Christoph Hellwig]

Pass the max_hw_sector limit loop sets at initialization time directly to
blk_mq_alloc_disk instead of updating it right after the allocation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
---
 drivers/block/loop.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 7abeb586942677..26c8ea79086798 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -1971,6 +1971,12 @@ static const struct blk_mq_ops loop_mq_ops = {
 
 static int loop_add(int i)
 {
+	struct queue_limits lim = {
+		/*
+		 * Random number picked from the historic block max_sectors cap.
+		 */
+		.max_hw_sectors		= 2560u,
+	};
 	struct loop_device *lo;
 	struct gendisk *disk;
 	int err;
@@ -2014,16 +2020,13 @@ static int loop_add(int i)
 	if (err)
 		goto out_free_idr;
 
-	disk = lo->lo_disk = blk_mq_alloc_disk(&lo->tag_set, NULL, lo);
+	disk = lo->lo_disk = blk_mq_alloc_disk(&lo->tag_set, &lim, lo);
 	if (IS_ERR(disk)) {
 		err = PTR_ERR(disk);
 		goto out_cleanup_tags;
 	}
 	lo->lo_queue = lo->lo_disk->queue;
 
-	/* random number picked from the history block max_sectors cap */
-	blk_queue_max_hw_sectors(lo->lo_queue, 2560u);
-
 	/*
 	 * By default, we do buffer IO, so it doesn't make sense to enable
 	 * merge because the I/O submitted to backing file is handled page by
-- 
2.39.2

[PATCH 15/15] loop: use the atomic queue limits update API

[Christoph Hellwig]

Pass the default limits to blk_mq_alloc_disk and then use the
queue_limits_{start,commit}_update API to change the limits in an
atomic way on existing loop gendisks.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
---
 drivers/block/loop.c | 41 +++++++++++++++++++++++++----------------
 1 file changed, 25 insertions(+), 16 deletions(-)

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 26c8ea79086798..28a95fd366fea5 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -750,11 +750,11 @@ static void loop_sysfs_exit(struct loop_device *lo)
 				   &loop_attribute_group);
 }
 
-static void loop_config_discard(struct loop_device *lo)
+static void loop_config_discard(struct loop_device *lo,
+		struct queue_limits *lim)
 {
 	struct file *file = lo->lo_backing_file;
 	struct inode *inode = file->f_mapping->host;
-	struct request_queue *q = lo->lo_queue;
 	u32 granularity = 0, max_discard_sectors = 0;
 	struct kstatfs sbuf;
 
@@ -781,12 +781,12 @@ static void loop_config_discard(struct loop_device *lo)
 		granularity = sbuf.f_bsize;
 	}
 
-	blk_queue_max_discard_sectors(q, max_discard_sectors);
-	blk_queue_max_write_zeroes_sectors(q, max_discard_sectors);
+	lim->max_hw_discard_sectors = max_discard_sectors;
+	lim->max_write_zeroes_sectors = max_discard_sectors;
 	if (max_discard_sectors)
-		q->limits.discard_granularity = granularity;
+		lim->discard_granularity = granularity;
 	else
-		q->limits.discard_granularity = 0;
+		lim->discard_granularity = 0;
 }
 
 struct loop_worker {
@@ -975,6 +975,20 @@ loop_set_status_from_info(struct loop_device *lo,
 	return 0;
 }
 
+static int loop_reconfigure_limits(struct loop_device *lo, unsigned short bsize,
+		bool update_discard_settings)
+{
+	struct queue_limits lim;
+
+	lim = queue_limits_start_update(lo->lo_queue);
+	lim.logical_block_size = bsize;
+	lim.physical_block_size = bsize;
+	lim.io_min = bsize;
+	if (update_discard_settings)
+		loop_config_discard(lo, &lim);
+	return queue_limits_commit_update(lo->lo_queue, &lim);
+}
+
 static int loop_configure(struct loop_device *lo, blk_mode_t mode,
 			  struct block_device *bdev,
 			  const struct loop_config *config)
@@ -1072,11 +1086,10 @@ static int loop_configure(struct loop_device *lo, blk_mode_t mode,
 	else
 		bsize = 512;
 
-	blk_queue_logical_block_size(lo->lo_queue, bsize);
-	blk_queue_physical_block_size(lo->lo_queue, bsize);
-	blk_queue_io_min(lo->lo_queue, bsize);
+	error = loop_reconfigure_limits(lo, bsize, true);
+	if (WARN_ON_ONCE(error))
+		goto out_unlock;
 
-	loop_config_discard(lo);
 	loop_update_rotational(lo);
 	loop_update_dio(lo);
 	loop_sysfs_init(lo);
@@ -1143,9 +1156,7 @@ static void __loop_clr_fd(struct loop_device *lo, bool release)
 	lo->lo_offset = 0;
 	lo->lo_sizelimit = 0;
 	memset(lo->lo_file_name, 0, LO_NAME_SIZE);
-	blk_queue_logical_block_size(lo->lo_queue, 512);
-	blk_queue_physical_block_size(lo->lo_queue, 512);
-	blk_queue_io_min(lo->lo_queue, 512);
+	loop_reconfigure_limits(lo, 512, false);
 	invalidate_disk(lo->lo_disk);
 	loop_sysfs_exit(lo);
 	/* let user-space know about this change */
@@ -1477,9 +1488,7 @@ static int loop_set_block_size(struct loop_device *lo, unsigned long arg)
 	invalidate_bdev(lo->lo_device);
 
 	blk_mq_freeze_queue(lo->lo_queue);
-	blk_queue_logical_block_size(lo->lo_queue, arg);
-	blk_queue_physical_block_size(lo->lo_queue, arg);
-	blk_queue_io_min(lo->lo_queue, arg);
+	err = loop_reconfigure_limits(lo, arg, false);
 	loop_update_dio(lo);
 	blk_mq_unfreeze_queue(lo->lo_queue);
 
-- 
2.39.2

Re: atomic queue limits updates v5

[Jens Axboe]

On Tue, 13 Feb 2024 08:34:10 +0100, Christoph Hellwig wrote:
> currently queue limits updates are a mess in that they are updated one
> limit at a time, which makes both cross-checking them against other
> limits hard, and also makes it hard to provide atomicy.
> 
> This series tries to change this by updating the whole set of queue
> limits atomically.   This in done in two ways:
> 
> [...]

Applied, thanks!

[01/15] block: move max_{open,active}_zones to struct queue_limits
        commit: 8c4955c069ea3b77dc63b55d13afa9341e894849
[02/15] block: refactor disk_update_readahead
        commit: b9947297d00b9c75b271db88165e39c0208bec2e
[03/15] block: decouple blk_set_stacking_limits from blk_set_default_limits
        commit: c490f226a0ea22639e81ac34edc884e238ea955a
[04/15] block: add an API to atomically update queue limits
        commit: d690cb8ae14bd377d422b7905b6959c7e7a45b95
[05/15] block: use queue_limits_commit_update in queue_max_sectors_store
        commit: 0327ca9d53bfbb0918867313049bba7046900f73
[06/15] block: add a max_user_discard_sectors queue limit
        commit: 4f563a64732dabb2677c7d1232a8f714a18b41b3
[07/15] block: use queue_limits_commit_update in queue_discard_max_store
        commit: ff956a3be95b45b2a823693a8c9db740939ca35e
[08/15] block: pass a queue_limits argument to blk_alloc_queue
        commit: ad751ba1f8d5d4f4f4b429b552a154e888524a93
[09/15] block: pass a queue_limits argument to blk_mq_init_queue
        commit: 9ac4dd8c47d533eb420af6a679e66ec74771125c
[10/15] block: pass a queue_limits argument to blk_mq_alloc_disk
        commit: 27e32cd23fed1ab88098897897dcb9ec2bdba4de
[11/15] virtio_blk: split virtblk_probe
        commit: 718628adfcfdc80466eb42cd9c615d1d5514f74c
[12/15] virtio_blk: pass queue_limits to blk_mq_alloc_disk
        commit: 8b837256560c783415b42748959900befcde2d00
[13/15] loop: cleanup loop_config_discard
        commit: 65bdd16f8c72bb2178f5e4db40305bef6c96b309
[14/15] loop: pass queue_limits to blk_mq_alloc_disk
        commit: 02aed4a1f2c355e41d82a8e9831031ca9e0eb45d
[15/15] loop: use the atomic queue limits update API
        commit: 473516b361936cbc27d7728df649a5b3094b6170

Best regards,
-- 
Jens Axboe

atomic queue limits updates v4

[Christoph Hellwig]

Hi Jens,

currently queue limits updates are a mess in that they are updated one
limit at a time, which makes both cross-checking them against other
limits hard, and also makes it hard to provide atomicy.

This series tries to change this by updating the whole set of queue
limits atomically.   This in done in two ways:

 - for the initial setup the queue_limits structure is simply passed to
   the queue/disk allocation helpers and applies there after validation.
 - for the (relatively few) cases that update limits at runtime a pair
   of helpers to take a snapshot of the current limits and to commit it
   after picking up the callers changes are provided.

As the series is big enough it only converts two drivers - virtio_blk as
a heavily used driver in virtualized setups, and loop as one that actually
does runtime updates while being fairly simple.  I plan to update most
drivers for this merge window, although SCSI will probably have to wait
for the next one given that it will need extensive API changes in the
LLDD and ULD interfaces.

Chances since v3:
 - fix a max_user_discard_sectors bisection hazard
 - fix the max_user_discard_sectors initialization for the new API.
   This led to some major refactoring, so there is a new patch and
   I've dropped the reviews for two existing ones that have major
   modifications

Chances since v2:
 - fix the physical block size default
 - use PAGE_SECTORS_SHIFT more 

Chances since v1:
 - remove a spurious NULL return in blk_alloc_queue
 - keep the existing max_discard_sectors == 0 behavior
 - drop the patch nvme discard limit update hack - it will go into
   the series updating nvme instead
 - drop a chunk_sector check
 - use PAGE_SECTORS in a few places
 - document the checks and defaults in blk_validate_limits
 - various spelling fixes

Diffstat:
 arch/um/drivers/ubd_kern.c          |    2 
 block/blk-core.c                    |   27 ++-
 block/blk-mq.c                      |   27 +--
 block/blk-settings.c                |  276 +++++++++++++++++++++++++++------
 block/blk-sysfs.c                   |   59 +++----
 block/blk.h                         |    4 
 block/bsg-lib.c                     |    2 
 block/genhd.c                       |    5 
 drivers/block/amiflop.c             |    2 
 drivers/block/aoe/aoeblk.c          |    2 
 drivers/block/ataflop.c             |    2 
 drivers/block/floppy.c              |    2 
 drivers/block/loop.c                |   75 ++++-----
 drivers/block/mtip32xx/mtip32xx.c   |    2 
 drivers/block/nbd.c                 |    2 
 drivers/block/null_blk/main.c       |    2 
 drivers/block/ps3disk.c             |    2 
 drivers/block/rbd.c                 |    2 
 drivers/block/rnbd/rnbd-clt.c       |    2 
 drivers/block/sunvdc.c              |    2 
 drivers/block/swim.c                |    2 
 drivers/block/swim3.c               |    2 
 drivers/block/ublk_drv.c            |    2 
 drivers/block/virtio_blk.c          |  299 ++++++++++++++++++------------------
 drivers/block/xen-blkfront.c        |    2 
 drivers/block/z2ram.c               |    2 
 drivers/cdrom/gdrom.c               |    2 
 drivers/memstick/core/ms_block.c    |    2 
 drivers/memstick/core/mspro_block.c |    2 
 drivers/mmc/core/queue.c            |    2 
 drivers/mtd/mtd_blkdevs.c           |    2 
 drivers/mtd/ubi/block.c             |    2 
 drivers/nvme/host/apple.c           |    2 
 drivers/nvme/host/core.c            |    8 
 drivers/s390/block/dasd_genhd.c     |    2 
 drivers/s390/block/scm_blk.c        |    2 
 drivers/scsi/scsi_scan.c            |    2 
 drivers/ufs/core/ufshcd.c           |    2 
 include/linux/blk-mq.h              |   10 -
 include/linux/blkdev.h              |   36 +++-
 40 files changed, 547 insertions(+), 337 deletions(-)

[PATCH 04/15] block: add an API to atomically update queue limits

[Christoph Hellwig]

Add a new queue_limits_{start,commit}_update pair of functions that
allows taking an atomic snapshot of queue limits, update it, and
commit it if it passes validity checking.  Also use the low-level
validation helper to implement blk_set_default_limits instead of
duplicating the initialization.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/blk-core.c       |   1 +
 block/blk-settings.c   | 228 ++++++++++++++++++++++++++++++++++-------
 block/blk.h            |   4 +-
 include/linux/blkdev.h |  23 +++++
 4 files changed, 218 insertions(+), 38 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index 2b11d8325fde68..cb56724a8dfb25 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -425,6 +425,7 @@ struct request_queue *blk_alloc_queue(int node_id)
 	mutex_init(&q->debugfs_mutex);
 	mutex_init(&q->sysfs_lock);
 	mutex_init(&q->sysfs_dir_lock);
+	mutex_init(&q->limits_lock);
 	mutex_init(&q->rq_qos_mutex);
 	spin_lock_init(&q->queue_lock);
 
diff --git a/block/blk-settings.c b/block/blk-settings.c
index 1cae2db41490d2..27b9b4a2a85395 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -25,42 +25,6 @@ void blk_queue_rq_timeout(struct request_queue *q, unsigned int timeout)
 }
 EXPORT_SYMBOL_GPL(blk_queue_rq_timeout);
 
-/**
- * blk_set_default_limits - reset limits to default values
- * @lim:  the queue_limits structure to reset
- *
- * Description:
- *   Returns a queue_limit struct to its default state.
- */
-void blk_set_default_limits(struct queue_limits *lim)
-{
-	lim->max_segments = BLK_MAX_SEGMENTS;
-	lim->max_discard_segments = 1;
-	lim->max_integrity_segments = 0;
-	lim->seg_boundary_mask = BLK_SEG_BOUNDARY_MASK;
-	lim->virt_boundary_mask = 0;
-	lim->max_segment_size = BLK_MAX_SEGMENT_SIZE;
-	lim->max_sectors = lim->max_hw_sectors = BLK_SAFE_MAX_SECTORS;
-	lim->max_user_sectors = lim->max_dev_sectors = 0;
-	lim->chunk_sectors = 0;
-	lim->max_write_zeroes_sectors = 0;
-	lim->max_zone_append_sectors = 0;
-	lim->max_discard_sectors = 0;
-	lim->max_hw_discard_sectors = 0;
-	lim->max_secure_erase_sectors = 0;
-	lim->discard_granularity = 512;
-	lim->discard_alignment = 0;
-	lim->discard_misaligned = 0;
-	lim->logical_block_size = lim->physical_block_size = lim->io_min = 512;
-	lim->bounce = BLK_BOUNCE_NONE;
-	lim->alignment_offset = 0;
-	lim->io_opt = 0;
-	lim->misaligned = 0;
-	lim->zoned = false;
-	lim->zone_write_granularity = 0;
-	lim->dma_alignment = 511;
-}
-
 /**
  * blk_set_stacking_limits - set default limits for stacking devices
  * @lim:  the queue_limits structure to reset
@@ -99,6 +63,198 @@ static void blk_apply_bdi_limits(struct backing_dev_info *bdi,
 	bdi->io_pages = lim->max_sectors >> PAGE_SECTORS_SHIFT;
 }
 
+static int blk_validate_zoned_limits(struct queue_limits *lim)
+{
+	if (!lim->zoned) {
+		if (WARN_ON_ONCE(lim->max_open_zones) ||
+		    WARN_ON_ONCE(lim->max_active_zones) ||
+		    WARN_ON_ONCE(lim->zone_write_granularity) ||
+		    WARN_ON_ONCE(lim->max_zone_append_sectors))
+			return -EINVAL;
+		return 0;
+	}
+
+	if (WARN_ON_ONCE(!IS_ENABLED(CONFIG_BLK_DEV_ZONED)))
+		return -EINVAL;
+
+	if (lim->zone_write_granularity < lim->logical_block_size)
+		lim->zone_write_granularity = lim->logical_block_size;
+
+	if (lim->max_zone_append_sectors) {
+		/*
+		 * The Zone Append size is limited by the maximum I/O size
+		 * and the zone size given that it can't span zones.
+		 */
+		lim->max_zone_append_sectors =
+			min3(lim->max_hw_sectors,
+			     lim->max_zone_append_sectors,
+			     lim->chunk_sectors);
+	}
+
+	return 0;
+}
+
+/*
+ * Check that the limits in lim are valid, initialize defaults for unset
+ * values, and cap values based on others where needed.
+ */
+static int blk_validate_limits(struct queue_limits *lim)
+{
+	unsigned int max_hw_sectors;
+
+	/*
+	 * Unless otherwise specified, default to 512 byte logical blocks and a
+	 * physical block size equal to the logical block size.
+	 */
+	if (!lim->logical_block_size)
+		lim->logical_block_size = SECTOR_SIZE;
+	if (lim->physical_block_size < lim->logical_block_size)
+		lim->physical_block_size = lim->logical_block_size;
+
+	/*
+	 * The minimum I/O size defaults to the physical block size unless
+	 * explicitly overridden.
+	 */
+	if (lim->io_min < lim->physical_block_size)
+		lim->io_min = lim->physical_block_size;
+
+	/*
+	 * max_hw_sectors has a somewhat weird default for historical reason,
+	 * but driver really should set their own instead of relying on this
+	 * value.
+	 *
+	 * The block layer relies on the fact that every driver can
+	 * handle at lest a page worth of data per I/O, and needs the value
+	 * aligned to the logical block size.
+	 */
+	if (!lim->max_hw_sectors)
+		lim->max_hw_sectors = BLK_SAFE_MAX_SECTORS;
+	if (WARN_ON_ONCE(lim->max_hw_sectors < PAGE_SECTORS))
+		return -EINVAL;
+	lim->max_hw_sectors = round_down(lim->max_hw_sectors,
+			lim->logical_block_size >> SECTOR_SHIFT);
+
+	/*
+	 * The actual max_sectors value is a complex beast and also takes the
+	 * max_dev_sectors value (set by SCSI ULPs) and a user configurable
+	 * value into account.  The ->max_sectors value is always calculated
+	 * from these, so directly setting it won't have any effect.
+	 */
+	max_hw_sectors = min_not_zero(lim->max_hw_sectors,
+				lim->max_dev_sectors);
+	if (lim->max_user_sectors) {
+		if (lim->max_user_sectors > max_hw_sectors ||
+		    lim->max_user_sectors < PAGE_SIZE / SECTOR_SIZE)
+			return -EINVAL;
+		lim->max_sectors = min(max_hw_sectors, lim->max_user_sectors);
+	} else {
+		lim->max_sectors = min(max_hw_sectors, BLK_DEF_MAX_SECTORS_CAP);
+	}
+	lim->max_sectors = round_down(lim->max_sectors,
+			lim->logical_block_size >> SECTOR_SHIFT);
+
+	/*
+	 * Random default for the maximum number of sectors.  Driver should not
+	 * rely on this and set their own.
+	 */
+	if (!lim->max_segments)
+		lim->max_segments = BLK_MAX_SEGMENTS;
+
+	lim->max_discard_sectors = lim->max_hw_discard_sectors;
+	if (!lim->max_discard_segments)
+		lim->max_discard_segments = 1;
+
+	if (lim->discard_granularity < lim->physical_block_size)
+		lim->discard_granularity = lim->physical_block_size;
+
+	/*
+	 * By default there is no limit on the segment boundary alignment,
+	 * but if there is one it can't be smaller than the page size as
+	 * that would break all the normal I/O patterns.
+	 */
+	if (!lim->seg_boundary_mask)
+		lim->seg_boundary_mask = BLK_SEG_BOUNDARY_MASK;
+	if (WARN_ON_ONCE(lim->seg_boundary_mask < PAGE_SIZE - 1))
+		return -EINVAL;
+
+	/*
+	 * The maximum segment size has an odd historic 64k default that
+	 * drivers probably should override.  Just like the I/O size we
+	 * require drivers to at least handle a full page per segment.
+	 */
+	if (!lim->max_segment_size)
+		lim->max_segment_size = BLK_MAX_SEGMENT_SIZE;
+	if (WARN_ON_ONCE(lim->max_segment_size < PAGE_SIZE))
+		return -EINVAL;
+
+	/*
+	 * Devices that require a virtual boundary do not support scatter/gather
+	 * I/O natively, but instead require a descriptor list entry for each
+	 * page (which might not be identical to the Linux PAGE_SIZE).  Because
+	 * of that they are not limited by our notion of "segment size".
+	 */
+	if (lim->virt_boundary_mask) {
+		if (WARN_ON_ONCE(lim->max_segment_size &&
+				 lim->max_segment_size != UINT_MAX))
+			return -EINVAL;
+		lim->max_segment_size = UINT_MAX;
+	}
+
+	/*
+	 * We require drivers to at least do logical block aligned I/O, but
+	 * historically could not check for that due to the separate calls
+	 * to set the limits.  Once the transition is finished the check
+	 * below should be narrowed down to check the logical block size.
+	 */
+	if (!lim->dma_alignment)
+		lim->dma_alignment = SECTOR_SIZE - 1;
+	if (WARN_ON_ONCE(lim->dma_alignment > PAGE_SIZE))
+		return -EINVAL;
+
+	if (lim->alignment_offset) {
+		lim->alignment_offset &= (lim->physical_block_size - 1);
+		lim->misaligned = 0;
+	}
+
+	return blk_validate_zoned_limits(lim);
+}
+
+/*
+ * Set the default limits for a newly allocated queue.  @lim contains the
+ * initial limits set by the driver, which could be no limit in which case
+ * all fields are cleared to zero.
+ */
+int blk_set_default_limits(struct queue_limits *lim)
+{
+	return blk_validate_limits(lim);
+}
+
+/**
+ * queue_limits_commit_update - commit an atomic update of queue limits
+ * @q:		queue to update
+ * @lim:	limits to apply
+ *
+ * Apply the limits in @lim that were obtained from queue_limits_start_update()
+ * and updated by the caller to @q.
+ *
+ * Returns 0 if successful, else a negative error code.
+ */
+int queue_limits_commit_update(struct request_queue *q,
+		struct queue_limits *lim)
+	__releases(q->limits_lock)
+{
+	int error = blk_validate_limits(lim);
+
+	if (!error) {
+		q->limits = *lim;
+		if (q->disk)
+			blk_apply_bdi_limits(q->disk->bdi, lim);
+	}
+	mutex_unlock(&q->limits_lock);
+	return error;
+}
+EXPORT_SYMBOL_GPL(queue_limits_commit_update);
+
 /**
  * blk_queue_bounce_limit - set bounce buffer limit for queue
  * @q: the request queue for the device
diff --git a/block/blk.h b/block/blk.h
index 913c93838a01bf..7c30e2ac8ebcd3 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -330,7 +330,7 @@ void blk_rq_set_mixed_merge(struct request *rq);
 bool blk_rq_merge_ok(struct request *rq, struct bio *bio);
 enum elv_merge blk_try_merge(struct request *rq, struct bio *bio);
 
-void blk_set_default_limits(struct queue_limits *lim);
+int blk_set_default_limits(struct queue_limits *lim);
 int blk_dev_init(void);
 
 /*
@@ -448,7 +448,7 @@ static inline void bio_release_page(struct bio *bio, struct page *page)
 		unpin_user_page(page);
 }
 
-struct request_queue *blk_alloc_queue(int node_id);
+struct request_queue *blk_alloc_queue(struct queue_limits *lim, int node_id);
 
 int disk_scan_partitions(struct gendisk *disk, blk_mode_t mode);
 
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index de9251922f7583..97c01efed68253 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -473,6 +473,7 @@ struct request_queue {
 
 	struct mutex		sysfs_lock;
 	struct mutex		sysfs_dir_lock;
+	struct mutex		limits_lock;
 
 	/*
 	 * for reusing dead hctx instance in case of updating
@@ -861,6 +862,28 @@ static inline unsigned int blk_chunk_sectors_left(sector_t offset,
 	return chunk_sectors - (offset & (chunk_sectors - 1));
 }
 
+/**
+ * queue_limits_start_update - start an atomic update of queue limits
+ * @q:		queue to update
+ *
+ * This functions starts an atomic update of the queue limits.  It takes a lock
+ * to prevent other updates and returns a snapshot of the current limits that
+ * the caller can modify.  The caller must call queue_limits_commit_update()
+ * to finish the update.
+ *
+ * Context: process context.  The caller must have frozen the queue or ensured
+ * that there is outstanding I/O by other means.
+ */
+static inline struct queue_limits
+queue_limits_start_update(struct request_queue *q)
+	__acquires(q->limits_lock)
+{
+	mutex_lock(&q->limits_lock);
+	return q->limits;
+}
+int queue_limits_commit_update(struct request_queue *q,
+		struct queue_limits *lim);
+
 /*
  * Access functions for manipulating queue properties
  */
-- 
2.39.2

Re: [PATCH 04/15] block: add an API to atomically update queue limits

[Damien Le Moal]

On 2/12/24 15:45, Christoph Hellwig wrote:
> Add a new queue_limits_{start,commit}_update pair of functions that
> allows taking an atomic snapshot of queue limits, update it, and
> commit it if it passes validity checking.  Also use the low-level
> validation helper to implement blk_set_default_limits instead of
> duplicating the initialization.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  block/blk-core.c       |   1 +
>  block/blk-settings.c   | 228 ++++++++++++++++++++++++++++++++++-------
>  block/blk.h            |   4 +-
>  include/linux/blkdev.h |  23 +++++
>  4 files changed, 218 insertions(+), 38 deletions(-)

[...]

> +	/*
> +	 * Random default for the maximum number of sectors.  Driver should not

s/sectors/segments ?

> +	 * rely on this and set their own.
> +	 */
> +	if (!lim->max_segments)
> +		lim->max_segments = BLK_MAX_SEGMENTS;

Other than the above, looks OK to me.

Reviewed-by: Damien Le Moal <dlemoal@kernel.org>

-- 
Damien Le Moal
Western Digital Research

Re: [PATCH 04/15] block: add an API to atomically update queue limits

[Christoph Hellwig]

On Mon, Feb 12, 2024 at 04:24:39PM +0900, Damien Le Moal wrote:
> 
> [...]
> 
> > +	/*
> > +	 * Random default for the maximum number of sectors.  Driver should not
> 
> s/sectors/segments ?

Yes.

Re: [PATCH 04/15] block: add an API to atomically update queue limits

[Hannes Reinecke]

On 2/12/24 14:45, Christoph Hellwig wrote:
> Add a new queue_limits_{start,commit}_update pair of functions that
> allows taking an atomic snapshot of queue limits, update it, and
> commit it if it passes validity checking.  Also use the low-level
> validation helper to implement blk_set_default_limits instead of
> duplicating the initialization.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>   block/blk-core.c       |   1 +
>   block/blk-settings.c   | 228 ++++++++++++++++++++++++++++++++++-------
>   block/blk.h            |   4 +-
>   include/linux/blkdev.h |  23 +++++
>   4 files changed, 218 insertions(+), 38 deletions(-)
> 
> diff --git a/block/blk-core.c b/block/blk-core.c
> index 2b11d8325fde68..cb56724a8dfb25 100644
> --- a/block/blk-core.c
> +++ b/block/blk-core.c
> @@ -425,6 +425,7 @@ struct request_queue *blk_alloc_queue(int node_id)
>   	mutex_init(&q->debugfs_mutex);
>   	mutex_init(&q->sysfs_lock);
>   	mutex_init(&q->sysfs_dir_lock);
> +	mutex_init(&q->limits_lock);
>   	mutex_init(&q->rq_qos_mutex);
>   	spin_lock_init(&q->queue_lock);
>   
> diff --git a/block/blk-settings.c b/block/blk-settings.c
> index 1cae2db41490d2..27b9b4a2a85395 100644
> --- a/block/blk-settings.c
> +++ b/block/blk-settings.c
> @@ -25,42 +25,6 @@ void blk_queue_rq_timeout(struct request_queue *q, unsigned int timeout)
>   }
>   EXPORT_SYMBOL_GPL(blk_queue_rq_timeout);
>   
> -/**
> - * blk_set_default_limits - reset limits to default values
> - * @lim:  the queue_limits structure to reset
> - *
> - * Description:
> - *   Returns a queue_limit struct to its default state.
> - */
> -void blk_set_default_limits(struct queue_limits *lim)
> -{
> -	lim->max_segments = BLK_MAX_SEGMENTS;
> -	lim->max_discard_segments = 1;
> -	lim->max_integrity_segments = 0;
> -	lim->seg_boundary_mask = BLK_SEG_BOUNDARY_MASK;
> -	lim->virt_boundary_mask = 0;
> -	lim->max_segment_size = BLK_MAX_SEGMENT_SIZE;
> -	lim->max_sectors = lim->max_hw_sectors = BLK_SAFE_MAX_SECTORS;
> -	lim->max_user_sectors = lim->max_dev_sectors = 0;
> -	lim->chunk_sectors = 0;
> -	lim->max_write_zeroes_sectors = 0;
> -	lim->max_zone_append_sectors = 0;
> -	lim->max_discard_sectors = 0;
> -	lim->max_hw_discard_sectors = 0;
> -	lim->max_secure_erase_sectors = 0;
> -	lim->discard_granularity = 512;
> -	lim->discard_alignment = 0;
> -	lim->discard_misaligned = 0;
> -	lim->logical_block_size = lim->physical_block_size = lim->io_min = 512;
> -	lim->bounce = BLK_BOUNCE_NONE;
> -	lim->alignment_offset = 0;
> -	lim->io_opt = 0;
> -	lim->misaligned = 0;
> -	lim->zoned = false;
> -	lim->zone_write_granularity = 0;
> -	lim->dma_alignment = 511;
> -}
> -
>   /**
>    * blk_set_stacking_limits - set default limits for stacking devices
>    * @lim:  the queue_limits structure to reset
> @@ -99,6 +63,198 @@ static void blk_apply_bdi_limits(struct backing_dev_info *bdi,
>   	bdi->io_pages = lim->max_sectors >> PAGE_SECTORS_SHIFT;
>   }
>   
> +static int blk_validate_zoned_limits(struct queue_limits *lim)
> +{
> +	if (!lim->zoned) {
> +		if (WARN_ON_ONCE(lim->max_open_zones) ||
> +		    WARN_ON_ONCE(lim->max_active_zones) ||
> +		    WARN_ON_ONCE(lim->zone_write_granularity) ||
> +		    WARN_ON_ONCE(lim->max_zone_append_sectors))
> +			return -EINVAL;
> +		return 0;
> +	}
> +
> +	if (WARN_ON_ONCE(!IS_ENABLED(CONFIG_BLK_DEV_ZONED)))
> +		return -EINVAL;
> +
> +	if (lim->zone_write_granularity < lim->logical_block_size)
> +		lim->zone_write_granularity = lim->logical_block_size;
> +
> +	if (lim->max_zone_append_sectors) {
> +		/*
> +		 * The Zone Append size is limited by the maximum I/O size
> +		 * and the zone size given that it can't span zones.
> +		 */
> +		lim->max_zone_append_sectors =
> +			min3(lim->max_hw_sectors,
> +			     lim->max_zone_append_sectors,
> +			     lim->chunk_sectors);
> +	}
> +
> +	return 0;
> +}
> +
> +/*
> + * Check that the limits in lim are valid, initialize defaults for unset
> + * values, and cap values based on others where needed.
> + */
> +static int blk_validate_limits(struct queue_limits *lim)
> +{
> +	unsigned int max_hw_sectors;
> +
> +	/*
> +	 * Unless otherwise specified, default to 512 byte logical blocks and a
> +	 * physical block size equal to the logical block size.
> +	 */
> +	if (!lim->logical_block_size)
> +		lim->logical_block_size = SECTOR_SIZE;
> +	if (lim->physical_block_size < lim->logical_block_size)
> +		lim->physical_block_size = lim->logical_block_size;
> +
> +	/*
> +	 * The minimum I/O size defaults to the physical block size unless
> +	 * explicitly overridden.
> +	 */
> +	if (lim->io_min < lim->physical_block_size)
> +		lim->io_min = lim->physical_block_size;
> +
> +	/*
> +	 * max_hw_sectors has a somewhat weird default for historical reason,
> +	 * but driver really should set their own instead of relying on this
> +	 * value.
> +	 *
> +	 * The block layer relies on the fact that every driver can
> +	 * handle at lest a page worth of data per I/O, and needs the value
> +	 * aligned to the logical block size.
> +	 */
> +	if (!lim->max_hw_sectors)
> +		lim->max_hw_sectors = BLK_SAFE_MAX_SECTORS;
> +	if (WARN_ON_ONCE(lim->max_hw_sectors < PAGE_SECTORS))
> +		return -EINVAL;
> +	lim->max_hw_sectors = round_down(lim->max_hw_sectors,
> +			lim->logical_block_size >> SECTOR_SHIFT);
> +
> +	/*
> +	 * The actual max_sectors value is a complex beast and also takes the
> +	 * max_dev_sectors value (set by SCSI ULPs) and a user configurable
> +	 * value into account.  The ->max_sectors value is always calculated
> +	 * from these, so directly setting it won't have any effect.
> +	 */
> +	max_hw_sectors = min_not_zero(lim->max_hw_sectors,
> +				lim->max_dev_sectors);
> +	if (lim->max_user_sectors) {
> +		if (lim->max_user_sectors > max_hw_sectors ||
> +		    lim->max_user_sectors < PAGE_SIZE / SECTOR_SIZE)
> +			return -EINVAL;
> +		lim->max_sectors = min(max_hw_sectors, lim->max_user_sectors);
> +	} else {
> +		lim->max_sectors = min(max_hw_sectors, BLK_DEF_MAX_SECTORS_CAP);
> +	}
> +	lim->max_sectors = round_down(lim->max_sectors,
> +			lim->logical_block_size >> SECTOR_SHIFT);
> +
> +	/*
> +	 * Random default for the maximum number of sectors.  Driver should not
> +	 * rely on this and set their own.
> +	 */
> +	if (!lim->max_segments)
> +		lim->max_segments = BLK_MAX_SEGMENTS;
> +
> +	lim->max_discard_sectors = lim->max_hw_discard_sectors;
> +	if (!lim->max_discard_segments)
> +		lim->max_discard_segments = 1;
> +
> +	if (lim->discard_granularity < lim->physical_block_size)
> +		lim->discard_granularity = lim->physical_block_size;
> +
> +	/*
> +	 * By default there is no limit on the segment boundary alignment,
> +	 * but if there is one it can't be smaller than the page size as
> +	 * that would break all the normal I/O patterns.
> +	 */
> +	if (!lim->seg_boundary_mask)
> +		lim->seg_boundary_mask = BLK_SEG_BOUNDARY_MASK;
> +	if (WARN_ON_ONCE(lim->seg_boundary_mask < PAGE_SIZE - 1))
> +		return -EINVAL;
> +
> +	/*
> +	 * The maximum segment size has an odd historic 64k default that
> +	 * drivers probably should override.  Just like the I/O size we
> +	 * require drivers to at least handle a full page per segment.
> +	 */
> +	if (!lim->max_segment_size)
> +		lim->max_segment_size = BLK_MAX_SEGMENT_SIZE;
> +	if (WARN_ON_ONCE(lim->max_segment_size < PAGE_SIZE))
> +		return -EINVAL;
> +
> +	/*
> +	 * Devices that require a virtual boundary do not support scatter/gather
> +	 * I/O natively, but instead require a descriptor list entry for each
> +	 * page (which might not be identical to the Linux PAGE_SIZE).  Because
> +	 * of that they are not limited by our notion of "segment size".
> +	 */
> +	if (lim->virt_boundary_mask) {
> +		if (WARN_ON_ONCE(lim->max_segment_size &&
> +				 lim->max_segment_size != UINT_MAX))
> +			return -EINVAL;
> +		lim->max_segment_size = UINT_MAX;
> +	}
> +
> +	/*
> +	 * We require drivers to at least do logical block aligned I/O, but
> +	 * historically could not check for that due to the separate calls
> +	 * to set the limits.  Once the transition is finished the check
> +	 * below should be narrowed down to check the logical block size.
> +	 */
> +	if (!lim->dma_alignment)
> +		lim->dma_alignment = SECTOR_SIZE - 1;
> +	if (WARN_ON_ONCE(lim->dma_alignment > PAGE_SIZE))
> +		return -EINVAL;
> +
> +	if (lim->alignment_offset) {
> +		lim->alignment_offset &= (lim->physical_block_size - 1);
> +		lim->misaligned = 0;
> +	}
> +
> +	return blk_validate_zoned_limits(lim);
> +}
> +
> +/*
> + * Set the default limits for a newly allocated queue.  @lim contains the
> + * initial limits set by the driver, which could be no limit in which case
> + * all fields are cleared to zero.
> + */
> +int blk_set_default_limits(struct queue_limits *lim)
> +{
> +	return blk_validate_limits(lim);
> +}
> +
> +/**
> + * queue_limits_commit_update - commit an atomic update of queue limits
> + * @q:		queue to update
> + * @lim:	limits to apply
> + *
> + * Apply the limits in @lim that were obtained from queue_limits_start_update()
> + * and updated by the caller to @q.
> + *
> + * Returns 0 if successful, else a negative error code.
> + */
> +int queue_limits_commit_update(struct request_queue *q,
> +		struct queue_limits *lim)
> +	__releases(q->limits_lock)
> +{
> +	int error = blk_validate_limits(lim);
> +
> +	if (!error) {
> +		q->limits = *lim;
> +		if (q->disk)
> +			blk_apply_bdi_limits(q->disk->bdi, lim);
> +	}
> +	mutex_unlock(&q->limits_lock);
> +	return error;
> +}
> +EXPORT_SYMBOL_GPL(queue_limits_commit_update);
> +
>   /**
>    * blk_queue_bounce_limit - set bounce buffer limit for queue
>    * @q: the request queue for the device
> diff --git a/block/blk.h b/block/blk.h
> index 913c93838a01bf..7c30e2ac8ebcd3 100644
> --- a/block/blk.h
> +++ b/block/blk.h
> @@ -330,7 +330,7 @@ void blk_rq_set_mixed_merge(struct request *rq);
>   bool blk_rq_merge_ok(struct request *rq, struct bio *bio);
>   enum elv_merge blk_try_merge(struct request *rq, struct bio *bio);
>   
> -void blk_set_default_limits(struct queue_limits *lim);
> +int blk_set_default_limits(struct queue_limits *lim);
>   int blk_dev_init(void);
>   
>   /*
> @@ -448,7 +448,7 @@ static inline void bio_release_page(struct bio *bio, struct page *page)
>   		unpin_user_page(page);
>   }
>   
> -struct request_queue *blk_alloc_queue(int node_id);
> +struct request_queue *blk_alloc_queue(struct queue_limits *lim, int node_id);
>   
What is that doing here?
If you change the calling convention, shouldn't you modify the callers, too?

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
hare@suse.de                              +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), GF: Ivo Totev, Andrew McDonald,
Werner Knoblich