path: root/block/blk-settings.c

// 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 "blk.h"
#include "blk-rq-qos.h"
#include "blk-wbt.h"

void blk_queue_rq_timeout(struct request_queue *q, unsigned int timeout)
{
	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_zone_append_sectors = UINT_MAX;
	lim->max_user_discard_sectors = UINT_MAX;
}
EXPORT_SYMBOL(blk_set_stacking_limits);

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;
}

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;

	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;
}

static int blk_validate_integrity_limits(struct queue_limits *lim)
{
	struct blk_integrity *bi = &lim->integrity;

	if (!bi->tuple_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;
		}
		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->interval_exp)
		bi->interval_exp = ilog2(lim->logical_block_size);

	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;
}

static void blk_validate_atomic_write_limits(struct queue_limits *lim)
{
	unsigned int boundary_sectors;

	if (!lim->atomic_write_hw_max)
		goto unsupported;

	boundary_sectors = lim->atomic_write_hw_boundary >> SECTOR_SHIFT;

	if (boundary_sectors) {
		/*
		 * A feature of boundary support is that it disallows bios to
		 * be merged which would result in a merged request which
		 * crosses either a chunk sector or atomic write HW boundary,
		 * even though chunk sectors may be just set for performance.
		 * For simplicity, disallow atomic writes for a chunk sector
		 * which is non-zero and smaller than atomic write HW boundary.
		 * Furthermore, chunk sectors must be a multiple of atomic
		 * write HW boundary. Otherwise boundary support becomes
		 * complicated.
		 * Devices which do not conform to these rules can be dealt
		 * with if and when they show up.
		 */
		if (WARN_ON_ONCE(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.
 */
static int blk_validate_limits(struct queue_limits *lim)
{
	unsigned int max_hw_sectors;
	unsigned int logical_block_sectors;
	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;

	/*
	 * 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<