selftests/bpf: Reject graph kptr use after RCU unlockgrafted

Add a sleepable verifier test that loads a graph-node local kptr in an
explicit RCU read-side critical section, then passes its node to
bpf_rbtree_remove() after the section ends.

Before the verifier fix, the stale NON_OWN_REF flag makes the node look like
a live borrowed reference and the program is accepted. After the fix, the
pointer is demoted without NON_OWN_REF and the graph kfunc argument is
rejected.

Also exercise a graph kptr loaded while a spin lock provides implicit RCU
protection. The pointer must be invalidated when the lock is released, which
guards the required ordering between non-owning-reference invalidation and
RCU demotion.

Update the existing fault-protected load test state description. The
post-unlock pointer no longer carries NON_OWN_REF, but remains readable
because the load is rewritten to use BPF_PROBE_MEM.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20260904084325.52250-7-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 1055 insertions, 0 deletions

diff --git a/block/blk-settings.c b/block/blk-settings.c
new file mode 100644
index 000000000..827463129
--- /dev/null
+++ b/block/blk-settings.c
@@ -0,0 +1,1055 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Functions related to setting various queue properties from drivers
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/bio.h>
+#include <linux/blk-integrity.h>
+#include <linux/pagemap.h>
+#include <linux/backing-dev-defs.h>
+#include <linux/gcd.h>
+#include <linux/lcm.h>
+#include <linux/jiffies.h>
+#include <linux/gfp.h>
+#include <linux/dma-mapping.h>
+#include <linux/t10-pi.h>
+#include <linux/crc64.h>
+
+#include "blk.h"
+#include "blk-rq-qos.h"
+#include "blk-wbt.h"
+
+void blk_queue_rq_timeout(struct request_queue *q, unsigned int timeout)
+{
+	WRITE_ONCE(q->rq_timeout, timeout);
+}
+EXPORT_SYMBOL_GPL(blk_queue_rq_timeout);
+
+/**
+ * blk_set_stacking_limits - set default limits for stacking devices
+ * @lim:  the queue_limits structure to reset
+ *
+ * Prepare queue limits for applying limits from underlying devices using
+ * blk_stack_limits().
+ */
+void blk_set_stacking_limits(struct queue_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;
+	lim->max_discard_segments = USHRT_MAX;
+	lim->max_hw_sectors = UINT_MAX;
+	lim->max_segment_size = UINT_MAX;
+	lim->max_sectors = UINT_MAX;
+	lim->max_dev_sectors = UINT_MAX;
+	lim->max_write_zeroes_sectors = UINT_MAX;
+	lim->max_hw_wzeroes_unmap_sectors = UINT_MAX;
+	lim->max_user_wzeroes_unmap_sectors = UINT_MAX;
+	lim->max_hw_zone_append_sectors = UINT_MAX;
+	lim->max_user_discard_sectors = UINT_MAX;
+	lim->atomic_write_hw_max = UINT_MAX;
+}
+EXPORT_SYMBOL(blk_set_stacking_limits);
+
+void blk_apply_bdi_limits(struct backing_dev_info *bdi,
+		struct queue_limits *lim)
+{
+	u64 io_opt = lim->io_opt;
+
+	/*
+	 * For read-ahead of large files to be effective, we need to read ahead
+	 * at least twice the optimal I/O size. For rotational devices that do
+	 * not report an optimal I/O size (e.g. ATA HDDs), use the maximum I/O
+	 * size to avoid falling back to the (rather inefficient) small default
+	 * read-ahead size.
+	 *
+	 * There is no hardware limitation for the read-ahead size and the user
+	 * might have increased the read-ahead size through sysfs, so don't ever
+	 * decrease it.
+	 */
+	if (!io_opt && (lim->features & BLK_FEAT_ROTATIONAL))
+		io_opt = (u64)lim->max_sectors << SECTOR_SHIFT;
+
+	bdi->ra_pages = max3(bdi->ra_pages,
+				io_opt * 2 >> PAGE_SHIFT,
+				VM_READAHEAD_PAGES);
+	bdi->io_pages = lim->max_sectors >> PAGE_SECTORS_SHIFT;
+}
+
+static int blk_validate_zoned_limits(struct queue_limits *lim)
+{
+	if (!(lim->features & BLK_FEAT_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;
+
+	/*
+	 * Given that active zones include open zones, the maximum number of
+	 * open zones cannot be larger than the maximum number of active zones.
+	 */
+	if (lim->max_active_zones &&
+	    lim->max_open_zones > lim->max_active_zones)
+		return -EINVAL;
+
+	if (lim->zone_write_granularity < lim->logical_block_size)
+		lim->zone_write_granularity = lim->logical_block_size;
+
+	/*
+	 * The Zone Append size is limited by the maximum I/O size and the zone
+	 * size given that it can't span zones.
+	 *
+	 * If no max_hw_zone_append_sectors limit is provided, the block layer
+	 * will emulated it, else we're also bound by the hardware limit.
+	 */
+	lim->max_zone_append_sectors =
+		min_not_zero(lim->max_hw_zone_append_sectors,
+			min(lim->chunk_sectors, lim->max_hw_sectors));
+	return 0;
+}
+
+static int blk_validate_integrity_limits(struct queue_limits *lim)
+{
+	struct blk_integrity *bi = &lim->integrity;
+
+	if (!bi->metadata_size) {
+		if (bi->csum_type != BLK_INTEGRITY_CSUM_NONE ||
+		    bi->tag_size || ((bi->flags & BLK_INTEGRITY_REF_TAG))) {
+			pr_warn("invalid PI settings.\n");
+			return -EINVAL;
+		}
+		bi->flags |= BLK_INTEGRITY_NOGENERATE | BLK_INTEGRITY_NOVERIFY;
+		return 0;
+	}
+
+	if (!IS_ENABLED(CONFIG_BLK_DEV_INTEGRITY)) {
+		pr_warn("integrity support disabled.\n");
+		return -EINVAL;
+	}
+
+	if (bi->csum_type == BLK_INTEGRITY_CSUM_NONE &&
+	    (bi->flags & BLK_INTEGRITY_REF_TAG)) {
+		pr_warn("ref tag not support without checksum.\n");
+		return -EINVAL;
+	}
+
+	if (bi->pi_offset + bi->pi_tuple_size > bi->metadata_size) {
+		pr_warn("pi_offset (%u) + pi_tuple_size (%u) exceeds metadata_size (%u)\n",
+			bi->pi_offset, bi->pi_tuple_size, bi->metadata_size);
+		return -EINVAL;
+	}
+
+	switch (bi->csum_type) {
+	case BLK_INTEGRITY_CSUM_NONE:
+		if (bi->pi_tuple_size) {
+			pr_warn("pi_tuple_size must be 0 when checksum type is none\n");
+			return -EINVAL;
+		}
+		break;
+	case BLK_INTEGRITY_CSUM_CRC:
+	case BLK_INTEGRITY_CSUM_IP:
+		if (bi->pi_tuple_size != sizeof(struct t10_pi_tuple)) {
+			pr_warn("pi_tuple_size mismatch for T10 PI: expected %zu, got %u\n",
+				 sizeof(struct t10_pi_tuple),
+				 bi->pi_tuple_size);
+			return -EINVAL;
+		}
+		break;
+	case BLK_INTEGRITY_CSUM_CRC64:
+		if (bi->pi_tuple_size != sizeof(struct crc64_pi_tuple)) {
+			pr_warn("pi_tuple_size mismatch for CRC64 PI: expected %zu, got %u\n",
+				 sizeof(struct crc64_pi_tuple),
+				 bi->pi_tuple_size);
+			return -EINVAL;
+		}
+		break;
+	}
+
+	if (!bi->interval_exp) {
+		bi->interval_exp = ilog2(lim->logical_block_size);
+	} else if (bi->interval_exp < SECTOR_SHIFT ||
+		   bi->interval_exp > ilog2(lim->logical_block_size)) {
+		pr_warn("invalid interval_exp %u\n", bi->interval_exp);
+		return -EINVAL;
+	}
+
+	/*
+	 * Some IO controllers can not handle data intervals straddling
+	 * multiple bio_vecs.  For those, enforce alignment so that those are
+	 * never generated, and that each buffer is aligned as expected.
+	 */
+	if (!(bi->flags & BLK_SPLIT_INTERVAL_CAPABLE) && bi->csum_type) {
+		lim->dma_alignment = max(lim->dma_alignment,
+					(1U << bi->interval_exp) - 1);
+	}
+
+	/*
+	 * The block layer automatically adds integrity data for bios that don't
+	 * already have it.  Limit the I/O size so that a single maximum size
+	 * metadata segment can cover the integrity data for the entire I/O.
+	 */
+	lim->max_sectors = min(lim->max_sectors,
+		max_integrity_io_size(lim) >> SECTOR_SHIFT);
+
+	return 0;
+}
+
+/*
+ * Returns max guaranteed bytes which we can fit in a bio.
+ *
+ * We request that an atomic_write is ITER_UBUF iov_iter (so a single vector),
+ * so we assume that we can fit in at least PAGE_SIZE in a segment, apart from
+ * the first and last segments.
+ */
+static unsigned int blk_queue_max_guaranteed_bio(struct queue_limits *lim)
+{
+	unsigned int max_segments = min(BIO_MAX_VECS, lim->max_segments);
+	unsigned int length;
+
+	length = min(max_segments, 2) * lim->logical_block_size;
+	if (max_segments > 2)
+		length += (max_segments - 2) * PAGE_SIZE;
+
+	return length;
+}
+
+static void blk_atomic_writes_update_limits(struct queue_limits *lim)
+{
+	unsigned int unit_limit = min(lim->max_hw_sectors << SECTOR_SHIFT,
+					blk_queue_max_guaranteed_bio(lim));
+
+	unit_limit = rounddown_pow_of_two(unit_limit);
+
+	lim->atomic_write_max_sectors =
+		min(lim->atomic_write_hw_max >> SECTOR_SHIFT,
+			lim->max_hw_sectors);
+	lim->atomic_write_unit_min =
+		min(lim->atomic_write_hw_unit_min, unit_limit);
+	lim->atomic_write_unit_max =
+		min(lim->atomic_write_hw_unit_max, unit_limit);
+	lim->atomic_write_boundary_sectors =
+		lim->atomic_write_hw_boundary >> SECTOR_SHIFT;
+}
+
+/*
+ * Test whether any boundary is aligned with any chunk size. Stacked
+ * devices store any stripe size in t->chunk_sectors.
+ */
+static bool blk_valid_atomic_writes_boundary(unsigned int chunk_sectors,
+					unsigned int boundary_sectors)
+{
+	if (!chunk_sectors || !boundary_sectors)
+		return true;
+
+	if (boundary_sectors > chunk_sectors &&
+	    boundary_sectors % chunk_sectors)
+		return false;
+
+	if (chunk_sectors > boundary_sectors &&
+	    chunk_sectors % boundary_sectors)
+		return false;
+
+	return true;
+}
+
+static void blk_validate_atomic_write_limits(struct queue_limits *lim)
+{
+	unsigned int boundary_sectors;
+	unsigned int atomic_write_hw_max_sectors =
+			lim->atomic_write_hw_max >> SECTOR_SHIFT;
+
+	if (!(lim->features & BLK_FEAT_ATOMIC_WRITES))
+		goto unsupported;
+
+	/* UINT_MAX indicates stacked limits in initial state */
+	if (lim->atomic_write_hw_max == UINT_MAX)
+		goto unsupported;
+
+	if (!lim->atomic_write_hw_max)
+		goto unsupported;
+
+	if (WARN_ON_ONCE(!is_power_of_2(lim->atomic_write_hw_unit_min)))
+		goto unsupported;
+
+	if (WARN_ON_ONCE(!is_power_of_2(lim->atomic_write_hw_unit_max)))
+		goto unsupported;
+
+	if (WARN_ON_ONCE(lim->atomic_write_hw_unit_min >
+			 lim->atomic_write_hw_unit_max))
+		goto unsupported;
+
+	if (WARN_ON_ONCE(lim->atomic_write_hw_unit_max >
+			 lim->atomic_write_hw_max))
+		goto unsupported;
+
+	if (WARN_ON_ONCE(lim->chunk_sectors &&
+			atomic_write_hw_max_sectors > lim->chunk_sectors))
+		goto unsupported;
+
+	boundary_sectors = lim->atomic_write_hw_boundary >> SECTOR_SHIFT;
+
+	if (boundary_sectors) {
+		if (WARN_ON_ONCE(lim->atomic_write_hw_max >
+				 lim->atomic_write_hw_boundary))
+			goto unsupported;
+
+		if (WARN_ON_ONCE(!blk_valid_atomic_writes_boundary(
+			lim->chunk_sectors, boundary_sectors)))
+			goto unsupported;
+
+		/*
+		 * The boundary size just needs to be a multiple of unit_max
+		 * (and not necessarily a power-of-2), so this following check
+		 * could be relaxed in future.
+		 * Furthermore, if needed, unit_max could even be reduced so
+		 * that it is compliant with a !power-of-2 boundary.
+		 */
+		if (!is_power_of_2(boundary_sectors))
+			goto unsupported;
+	}
+
+	blk_atomic_writes_update_limits(lim);
+	return;
+
+unsupported:
+	lim->atomic_write_max_sectors = 0;
+	lim->atomic_write_boundary_sectors = 0;
+	lim->atomic_write_unit_min = 0;
+	lim->atomic_write_unit_max = 0;
+}
+
+/*
+ * Check that the limits in lim are valid, initialize defaults for unset
+ * values, and cap values based on others where needed.
+ */
+int blk_validate_limits(struct queue_limits *lim)
+{
+	unsigned int max_hw_sectors;
+	unsigned int logical_block_sectors;
+	unsigned long seg_size;
+	int err;
+
+	/*
+	 * 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;
+	else if (blk_validate_block_size(lim->logical_block_size)) {
+		pr_warn("Invalid logical block size (%d)\n", lim->logical_block_size);
+		return -EINVAL;
+	}
+	if (lim->physical_block_size < lim->logical_block_size) {
+		lim->physical_block_size = lim->logical_block_size;
+	} else if (!is_power_of_2(lim->physical_block_size)) {
+		pr_warn("Invalid physical block size (%d)\n", lim->physical_block_size);
+		return -EINVAL;
+	}
+
+	/*
+	 * 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;
+
+	/*
+	 * The optimal I/O size may not be aligned to physical block size
+	 * (because it may be limited by dma engines which have no clue about
+	 * block size of the disks attached to them), so we round it down here.
+	 */
+	lim->io_opt = round_down(lim->io_opt, 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;
+	logical_block_sectors = lim->logical_block_size >> SECTOR_SHIFT;
+	if (WARN_ON_ONCE(logical_block_sectors > lim->max_hw_sectors))
+		return -EINVAL;
+	lim->max_hw_sectors = round_down(lim->max_hw_sectors,
+			logical_block_sectors);
+
+	/*
+	 * 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 < BLK_MIN_SEGMENT_SIZE / SECTOR_SIZE)
+			return -EINVAL;
+		lim->max_sectors = min(max_hw_sectors, lim->max_user_sectors);
+	} else if (lim->io_opt > (BLK_DEF_MAX_SECTORS_CAP << SECTOR_SHIFT)) {
+		lim->max_sectors =
+			min(max_hw_sectors, lim->io_opt >> SECTOR_SHIFT);
+	} else if (lim->io_min > (BLK_DEF_MAX_SECTORS_CAP << SECTOR_SHIFT)) {
+		lim->max_sectors =
+			min(max_hw_sectors, lim->io_min >> SECTOR_SHIFT);
+	} else {
+		lim->max_sectors = min(max_hw_sectors, BLK_DEF_MAX_SECTORS_CAP);
+	}
+	lim->max_sectors = round_down(lim->max_sectors,
+			logical_block_sectors);
+
+	/*
+	 * 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;
+
+	if (lim->max_hw_wzeroes_unmap_sectors &&
+	    lim->max_hw_wzeroes_unmap_sectors != lim->max_write_zeroes_sectors)
+		return -EINVAL;
+	lim->max_wzeroes_unmap_sectors = min(lim->max_hw_wzeroes_unmap_sectors,
+			lim->max_user_wzeroes_unmap_sectors);
+
+	lim->max_discard_sectors =
+		min(lim->max_hw_discard_sectors, lim->max_user_discard_sectors);
+
+	/*
+	 * When discard is not supported, discard_granularity should be reported
+	 * as 0 to userspace.
+	 */
+	if (lim->max_discard_sectors)
+		lim->discard_granularity =
+			max(lim->discard_granularity, lim->physical_block_size);
+	else
+		lim->discard_granularity = 0;
+
+	if (!lim->max_discard_segments)
+		lim->max_discard_segments = 1;
+
+	/*
+	 * 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 < BLK_MIN_SEGMENT_SIZE - 1))
+		return -EINVAL;
+
+	/*
+	 * Stacking device may have both virtual boundary and max segment
+	 * size limit, so allow this setting now, and long-term the two
+	 * might need to move out of stacking limits since we have immutable
+	 * bvec and lower layer bio splitting is supposed to handle the two
+	 * correctly.
+	 */
+	if (lim->virt_boundary_mask) {
+		if (!lim->max_segment_size)
+			lim->max_segment_size = UINT_MAX;
+	} else {
+		/*
+		 * 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 < BLK_MIN_SEGMENT_SIZE))
+			return -EINVAL;
+	}
+
+	/* setup max segment size for building new segment in fast path */
+	if (lim->seg_boundary_mask > lim->max_segment_size - 1)
+		seg_size = lim->max_segment_size;
+	else
+		seg_size = lim->seg_boundary_mask + 1;
+	lim->max_fast_segment_size = min_t(unsigned int, seg_size, PAGE_SIZE);
+
+	/*
+	 * 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->flags &= ~BLK_FLAG_MISALIGNED;
+	}
+
+	if (!(lim->features & BLK_FEAT_WRITE_CACHE))
+		lim->features &= ~BLK_FEAT_FUA;
+
+	blk_validate_atomic_write_limits(lim);
+
+	err = blk_validate_integrity_limits(lim);
+	if (err)
+		return err;
+	return blk_validate_zoned_limits(lim);
+}
+EXPORT_SYMBOL_GPL(blk_validate_limits);
+
+/*
+ * 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)
+{
+	/*
+	 * Most defaults are set by capping the bounds in blk_validate_limits,
+	 * but these limits are special and need an explicit initialization to
+	 * the max value here.
+	 */
+	lim->max_user_discard_sectors = UINT_MAX;
+	lim->max_user_wzeroes_unmap_sectors = UINT_MAX;
+	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.  The caller must have frozen the queue or
+ * ensure that there are no outstanding I/Os by other means.
+ *
+ * Returns 0 if successful, else a negative error code.
+ */
+int queue_limits_commit_update(struct request_queue *q,
+		struct queue_limits *lim)
+{
+	int error;
+
+	lockdep_assert_held(&q->limits_lock);
+
+	error = blk_validate_limits(lim);
+	if (error)
+		goto out_unlock;
+
+#ifdef CONFIG_BLK_INLINE_ENCRYPTION
+	if (q->crypto_profile && lim->integrity.tag_size) {
+		pr_warn("blk-integrity: Integrity and hardware inline encryption are not supported together.\n");
+		error = -EINVAL;
+		goto out_unlock;
+	}
+#endif
+
+	q->limits = *lim;
+	if (q->disk)
+		blk_apply_bdi_limits(q->disk->bdi, lim);
+out_unlock:
+	mutex_unlock(&q->limits_lock);
+	return error;
+}
+EXPORT_SYMBOL_GPL(queue_limits_commit_update);
+
+/**
+ * queue_limits_commit_update_frozen - 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 with the new values by the caller to @q.  Freezes the queue
+ * before the update and unfreezes it after.
+ *
+ * Returns 0 if successful, else a negative error code.
+ */
+int queue_limits_commit_update_frozen(struct request_queue *q,
+		struct queue_limits *lim)
+{
+	unsigned int memflags;
+	int ret;
+
+	memflags = blk_mq_freeze_queue(q);
+	ret = queue_limits_commit_update(q, lim);
+	blk_mq_unfreeze_queue(q, memflags);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(queue_limits_commit_update_frozen);
+
+/**
+ * queue_limits_set - apply queue limits to queue
+ * @q:		queue to update
+ * @lim:	limits to apply
+ *
+ * Apply the limits in @lim that were freshly initialized to @q.
+ * To update existing limits use queue_limits_start_update() and
+ * queue_limits_commit_update() instead.
+ *
+ * Returns 0 if successful, else a negative error code.
+ */
+int queue_limits_set(struct request_queue *q, struct queue_limits *lim)
+{
+	mutex_lock(&q->limits_lock);
+	return queue_limits_commit_update(q, lim);
+}
+EXPORT_SYMBOL_GPL(queue_limits_set);
+
+static int queue_limit_alignment_offset(const struct queue_limits *lim,
+		sector_t sector)
+{
+	unsigned int granularity = max(lim->physical_block_size, lim->io_min);
+	unsigned int alignment = sector_div(sector, granularity >> SECTOR_SHIFT)
+		<< SECTOR_SHIFT;
+
+	return (granularity + lim->alignment_offset - alignment) % granularity;
+}
+
+static unsigned int queue_limit_discard_alignment(
+		const struct queue_limits *lim, sector_t sector)
+{
+	unsigned int alignment, granularity, offset;
+
+	if (!lim->max_discard_sectors)
+		return 0;
+
+	/* Why are these in bytes, not sectors? */
+	alignment = lim->discard_alignment >> SECTOR_SHIFT;
+	granularity = lim->discard_granularity >> SECTOR_SHIFT;
+
+	/* Offset of the partition start in 'granularity' sectors */
+	offset = sector_div(sector, granularity);
+
+	/* And why do we do this modulus *again* in blkdev_issue_discard()? */
+	offset = (granularity + alignment - offset) % granularity;
+
+	/* Turn it back into bytes, gaah */
+	return offset << SECTOR_SHIFT;
+}
+
+static unsigned int blk_round_down_sectors(unsigned int sectors, unsigned int lbs)
+{
+	sectors = round_down(sectors, lbs >> SECTOR_SHIFT);
+	if (sectors < PAGE_SIZE >> SECTOR_SHIFT)
+		sectors = PAGE_SIZE >> SECTOR_SHIFT;
+	return sectors;
+}
+
+/* Check if second and later bottom devices are compliant */
+static bool blk_stack_atomic_writes_tail(struct queue_limits *t,
+				struct queue_limits *b)
+{
+	/* We're not going to support different boundary sizes.. yet */
+	if (t->atomic_write_hw_boundary != b->atomic_write_hw_boundary)
+		return false;
+
+	/* Can't support this */
+	if (t->atomic_write_hw_unit_min > b->atomic_write_hw_unit_max)
+		return false;
+
+	/* Or this */
+	if (t->atomic_write_hw_unit_max < b->atomic_write_hw_unit_min)
+		return false;
+
+	t->atomic_write_hw_max = min(t->atomic_write_hw_max,
+				b->atomic_write_hw_max);
+	t->atomic_write_hw_unit_min = max(t->atomic_write_hw_unit_min,
+				b->atomic_write_hw_unit_min);
+	t->atomic_write_hw_unit_max = min(t->atomic_write_hw_unit_max,
+				b->atomic_write_hw_unit_max);
+	return true;
+}
+
+static void blk_stack_atomic_writes_chunk_sectors(struct queue_limits *t)
+{
+	unsigned int chunk_bytes;
+
+	if (!t->chunk_sectors)
+		return;
+
+	/*
+	 * If chunk sectors is so large that its value in bytes overflows
+	 * UINT_MAX, then just shift it down so it definitely will fit.
+	 * We don't support atomic writes of such a large size anyway.
+	 */
+	if (check_shl_overflow(t->chunk_sectors, SECTOR_SHIFT, &chunk_bytes))
+		chunk_bytes = t->chunk_sectors;
+
+	/*
+	 * Find values for limits which work for chunk size.
+	 * b->atomic_write_hw_unit_{min, max} may not be aligned with chunk
+	 * size, as the chunk size is not restricted to a power-of-2.
+	 * So we need to find highest power-of-2 which works for the chunk
+	 * size.
+	 * As an example scenario, we could have t->unit_max = 16K and
+	 * t->chunk_sectors = 24KB. For this case, reduce t->unit_max to a
+	 * value aligned with both limits, i.e. 8K in this example.
+	 */
+	t->atomic_write_hw_unit_max = min(t->atomic_write_hw_unit_max,
+					max_pow_of_two_factor(chunk_bytes));
+
+	t->atomic_write_hw_unit_min = min(t->atomic_write_hw_unit_min,
+					  t->atomic_write_hw_unit_max);
+	t->atomic_write_hw_max = min(t->atomic_write_hw_max, chunk_bytes);
+}
+
+/* Check stacking of first bottom device */
+static bool blk_stack_atomic_writes_head(struct queue_limits *t,
+				struct queue_limits *b)
+{
+	if (!blk_valid_atomic_writes_boundary(t->chunk_sectors,
+			b->atomic_write_hw_boundary >> SECTOR_SHIFT))
+		return false;
+
+	t->atomic_write_hw_unit_max = b->atomic_write_hw_unit_max;
+	t->atomic_write_hw_unit_min = b->atomic_write_hw_unit_min;
+	t->atomic_write_hw_max = b->atomic_write_hw_max;
+	t->atomic_write_hw_boundary = b->atomic_write_hw_boundary;
+	return true;
+}
+
+static void blk_stack_atomic_writes_limits(struct queue_limits *t,
+				struct queue_limits *b, sector_t start)
+{
+	if (!(b->features & BLK_FEAT_ATOMIC_WRITES))
+		goto unsupported;
+
+	if (!b->atomic_write_hw_unit_min)
+		goto unsupported;
+
+	if (!blk_atomic_write_start_sect_aligned(start, b))
+		goto unsupported;
+
+	/* UINT_MAX indicates no stacking of bottom devices yet */
+	if (t->atomic_write_hw_max == UINT_MAX) {
+		if (!blk_stack_atomic_writes_head(t, b))
+			goto unsupported;
+	} else {
+		if (!blk_stack_atomic_writes_tail(t, b))
+			goto unsupported;
+	}
+	blk_stack_atomic_writes_chunk_sectors(t);
+	return;
+
+unsupported:
+	t->atomic_write_hw_max = 0;
+	t->atomic_write_hw_unit_max = 0;
+	t->atomic_write_hw_unit_min = 0;
+	t->atomic_write_hw_boundary = 0;
+}
+
+/**
+ * blk_stack_limits - adjust queue_limits for stacked devices
+ * @t:	the stacking driver limits (top device)
+ * @b:  the underlying queue limits (bottom, component device)
+ * @start:  first data sector within component device
+ *
+ * Description:
+ *    This function is used by stacking drivers like MD and DM to ensure
+ *    that all component devices have compatible block sizes and
+ *    alignments.  The stacking driver must provide a queue_limits
+ *    struct (top) and then iteratively call the stacking function for
+ *    all component (bottom) devices.  The stacking function will
+ *    attempt to combine the values and ensure proper alignment.
+ *
+ *    Returns 0 if the top and bottom queue_limits are compatible.  The
+ *    top device's block sizes and alignment offsets may be adjusted to
+ *    ensure alignment with the bottom device. If no compatible sizes
+ *    and alignments exist, -1 is returned and the resulting top
+ *    queue_limits will have the misaligned flag set to indicate that
+ *    the alignment_offset is undefined.
+ */
+int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
+		     sector_t start)
+{
+	unsigned int top, bottom, alignment;
+	int ret = 0;
+
+	t->features |= (b->features & BLK_FEAT_INHERIT_MASK);
+
+	/*
+	 * Some feaures need to be supported both by the stacking driver and all
+	 * underlying devices.  The stacking driver sets these flags before
+	 * stacking the limits, and this will clear the flags if any of the
+	 * underlying devices does not support it.
+	 */
+	if (!(b->features & BLK_FEAT_NOWAIT))
+		t->features &= ~BLK_FEAT_NOWAIT;
+	if (!(b->features & BLK_FEAT_POLL))
+		t->features &= ~BLK_FEAT_POLL;
+	if (!(b->features & BLK_FEAT_PCI_P2PDMA))
+		t->features &= ~BLK_FEAT_PCI_P2PDMA;
+
+	t->flags |= (b->flags & BLK_FLAG_MISALIGNED);
+
+	t->max_sectors = min_not_zero(t->max_sectors, b->max_sectors);
+	t->max_user_sectors = min_not_zero(t->max_user_sectors,
+			b->max_user_sectors);
+	t->max_hw_sectors = min_not_zero(t->max_hw_sectors, b->max_hw_sectors);
+	t->max_dev_sectors = min_not_zero(t->max_dev_sectors, b->max_dev_sectors);
+	t->max_write_zeroes_sectors = min(t->max_write_zeroes_sectors,
+					b->max_write_zeroes_sectors);
+	t->max_user_wzeroes_unmap_sectors =
+			min(t->max_user_wzeroes_unmap_sectors,
+			    b->max_user_wzeroes_unmap_sectors);
+	t->max_hw_wzeroes_unmap_sectors =
+			min(t->max_hw_wzeroes_unmap_sectors,
+			    b->max_hw_wzeroes_unmap_sectors);
+
+	t->max_hw_zone_append_sectors = min(t->max_hw_zone_append_sectors,
+					b->max_hw_zone_append_sectors);
+
+	t->seg_boundary_mask = min_not_zero(t->seg_boundary_mask,
+					    b->seg_boundary_mask);
+	t->virt_boundary_mask = min_not_zero(t->virt_boundary_mask,
+					    b->virt_boundary_mask);
+
+	t->max_segments = min_not_zero(t->max_segments, b->max_segments);
+	t->max_discard_segments = min_not_zero(t->max_discard_segments,
+					       b->max_discard_segments);
+	t->max_integrity_segments = min_not_zero(t->max_integrity_segments,
+						 b->max_integrity_segments);
+
+	t->max_segment_size = min_not_zero(t->max_segment_size,
+					   b->max_segment_size);
+
+	alignment = queue_limit_alignment_offset(b, start);
+
+	/* Bottom device has different alignment.  Check that it is
+	 * compatible with the current top alignment.
+	 */
+	if (t->alignment_offset != alignment) {
+
+		top = max(t->physical_block_size, t->io_min)
+			+ t->alignment_offset;
+		bottom = max(b->physical_block_size, b->io_min) + alignment;
+
+		/* Verify that top and bottom intervals line up */
+		if (max(top, bottom) % min(top, bottom)) {
+			t->flags |= BLK_FLAG_MISALIGNED;
+			ret = -1;
+		}
+	}
+
+	t->logical_block_size = max(t->logical_block_size,
+				    b->logical_block_size);
+
+	t->physical_block_size = max(t->physical_block_size,
+				     b->physical_block_size);
+
+	t->io_min = max(t->io_min, b->io_min);
+	t->io_opt = lcm_not_zero(t->io_opt, b->io_opt);
+	t->dma_alignment = max(t->dma_alignment, b->dma_alignment);
+
+	/* Set non-power-of-2 compatible chunk_sectors boundary */
+	if (b->chunk_sectors)
+		t->chunk_sectors = gcd(t->chunk_sectors, b->chunk_sectors);
+
+	/* Physical block size a multiple of the logical block size? */
+	if (t->physical_block_size & (t->logical_block_size - 1)) {
+		t->physical_block_size = t->logical_block_size;
+		t->flags |= BLK_FLAG_MISALIGNED;
+		ret = -1;
+	}
+
+	/* Minimum I/O a multiple of the physical block size? */
+	if (t->io_min & (t->physical_block_size - 1)) {
+		t->io_min = t->physical_block_size;
+		t->flags |= BLK_FLAG_MISALIGNED;
+		ret = -1;
+	}
+
+	/* Optimal I/O a multiple of the physical block size? */
+	if (t->io_opt & (t->physical_block_size - 1)) {
+		t->io_opt = 0;
+		t->flags |= BLK_FLAG_MISALIGNED;
+		ret = -1;
+	}
+
+	/* chunk_sectors a multiple of the physical block size? */
+	if (t->chunk_sectors % (t->physical_block_size >> SECTOR_SHIFT)) {
+		t->chunk_sectors = 0;
+		t->flags |= BLK_FLAG_MISALIGNED;
+		ret = -1;
+	}
+
+	/* Find lowest common alignment_offset */
+	t->alignment_offset = lcm_not_zero(t->alignment_offset, alignment)
+		% max(t->physical_block_size, t->io_min);
+
+	/* Verify that new alignment_offset is on a logical block boundary */
+	if (t->alignment_offset & (t->logical_block_size - 1)) {
+		t->flags |= BLK_FLAG_MISALIGNED;
+		ret = -1;
+	}
+
+	t->max_sectors = blk_round_down_sectors(t->max_sectors, t->logical_block_size);
+	t->max_hw_sectors = blk_round_down_sectors(t->max_hw_sectors, t->logical_block_size);
+	t->max_dev_sectors = blk_round_down_sectors(t->max_dev_sectors, t->logical_block_size);
+
+	/* Discard alignment and granularity */
+	if (b->discard_granularity) {
+		alignment = queue_limit_discard_alignment(b, start);
+
+		t->max_discard_sectors = min_not_zero(t->max_discard_sectors,
+						      b->max_discard_sectors);
+		t->max_hw_discard_sectors = min_not_zero(t->max_hw_discard_sectors,
+							 b->max_hw_discard_sectors);
+		t->discard_granularity = max(t->discard_granularity,
+					     b->discard_granularity);
+		t->discard_alignment = lcm_not_zero(t->discard_alignment, alignment) %
+			t->discard_granularity;
+	}
+	t->max_secure_erase_sectors = min_not_zero(t->max_secure_erase_sectors,
+						   b->max_secure_erase_sectors);
+	t->zone_write_granularity = max(t->zone_write_granularity,
+					b->zone_write_granularity);
+	if (!(t->features & BLK_FEAT_ZONED)) {
+		t->zone_write_granularity = 0;
+		t->max_zone_append_sectors = 0;
+	}
+	blk_stack_atomic_writes_limits(t, b, start);
+
+	return ret;
+}
+EXPORT_SYMBOL(blk_stack_limits);
+
+/**
+ * queue_limits_stack_bdev - adjust queue_limits for stacked devices
+ * @t:	the stacking driver limits (top device)
+ * @bdev:  the underlying block device (bottom)
+ * @offset:  offset to beginning of data within component device
+ * @pfx: prefix to use for warnings logged
+ *
+ * Description:
+ *    This function is used by stacking drivers like MD and DM to ensure
+ *    that all component devices have compatible block sizes and
+ *    alignments.  The stacking driver must provide a queue_limits
+ *    struct (top) and then iteratively call the stacking function for
+ *    all component (bottom) devices.  The stacking function will
+ *    attempt to combine the values and ensure proper alignment.
+ */
+void queue_limits_stack_bdev(struct queue_limits *t, struct block_device *bdev,
+		sector_t offset, const char *pfx)
+{
+	if (blk_stack_limits(t, bdev_limits(bdev),
+			get_start_sect(bdev) + offset))
+		pr_notice("%s: Warning: Device %pg is misaligned\n",
+			pfx, bdev);
+}
+EXPORT_SYMBOL_GPL(queue_limits_stack_bdev);
+
+/**
+ * queue_limits_stack_integrity - stack integrity profile
+ * @t: target queue limits
+ * @b: base queue limits
+ *
+ * Check if the integrity profile in the @b can be stacked into the
+ * target @t.  Stacking is possible if either:
+ *
+ *   a) does not have any integrity information stacked into it yet
+ *   b) the integrity profile in @b is identical to the one in @t
+ *
+ * If @b can be stacked into @t, return %true.  Else return %false and clear the
+ * integrity information in @t.
+ */
+bool queue_limits_stack_integrity(struct queue_limits *t,
+		struct queue_limits *b)
+{
+	struct blk_integrity *ti = &t->integrity;
+	struct blk_integrity *bi = &b->integrity;
+
+	if (!IS_ENABLED(CONFIG_BLK_DEV_INTEGRITY))
+		return true;
+
+	if (ti->flags & BLK_INTEGRITY_STACKED) {
+		if (ti->metadata_size != bi->metadata_size)
+			goto incompatible;
+		if (ti->interval_exp != bi->interval_exp)
+			goto incompatible;
+		if (ti->tag_size != bi->tag_size)
+			goto incompatible;
+		if (ti->csum_type != bi->csum_type)
+			goto incompatible;
+		if (ti->pi_tuple_size != bi->pi_tuple_size)
+			goto incompatible;
+		if ((ti->flags & BLK_INTEGRITY_REF_TAG) !=
+		    (bi->flags & BLK_INTEGRITY_REF_TAG))
+			goto incompatible;
+		if ((ti->flags & BLK_SPLIT_INTERVAL_CAPABLE) &&
+		    !(bi->flags & BLK_SPLIT_INTERVAL_CAPABLE))
+			ti->flags &= ~BLK_SPLIT_INTERVAL_CAPABLE;
+	} else {
+		ti->flags = BLK_INTEGRITY_STACKED;
+		ti->flags |= (bi->flags & BLK_INTEGRITY_DEVICE_CAPABLE) |
+			     (bi->flags & BLK_INTEGRITY_REF_TAG) |
+			     (bi->flags & BLK_SPLIT_INTERVAL_CAPABLE);
+		ti->csum_type = bi->csum_type;
+		ti->pi_tuple_size = bi->pi_tuple_size;
+		ti->metadata_size = bi->metadata_size;
+		ti->pi_offset = bi->pi_offset;
+		ti->interval_exp = bi->interval_exp;
+		ti->tag_size = bi->tag_size;
+	}
+	return true;
+
+incompatible:
+	memset(ti, 0, sizeof(*ti));
+	return false;
+}
+EXPORT_SYMBOL_GPL(queue_limits_stack_integrity);
+
+/**
+ * blk_set_queue_depth - tell the block layer about the device queue depth
+ * @q:		the request queue for the device
+ * @depth:		queue depth
+ *
+ */
+void blk_set_queue_depth(struct request_queue *q, unsigned int depth)
+{
+	q->queue_depth = depth;
+	rq_qos_queue_depth_changed(q);
+}
+EXPORT_SYMBOL(blk_set_queue_depth);
+
+int bdev_alignment_offset(struct block_device *bdev)
+{
+	struct request_queue *q = bdev_get_queue(bdev);
+
+	if (q->limits.flags & BLK_FLAG_MISALIGNED)
+		return -1;
+	if (bdev_is_partition(bdev))
+		return queue_limit_alignment_offset(&q->limits,
+				bdev->bd_start_sect);
+	return q->limits.alignment_offset;
+}
+EXPORT_SYMBOL_GPL(bdev_alignment_offset);
+
+unsigned int bdev_discard_alignment(struct block_device *bdev)
+{
+	struct request_queue *q = bdev_get_queue(bdev);
+
+	if (bdev_is_partition(bdev))
+		return queue_limit_discard_alignment(&q->limits,
+				bdev->bd_start_sect);
+	return q->limits.discard_alignment;
+}
+EXPORT_SYMBOL_GPL(bdev_discard_alignment);