index : linux	frominto-error master
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Branch	Commit message	Author	Age
frominto-error	WIP: From and Into impl for Error type	Matthias Beyer	4 years
master	Merge tag 'for-5.11-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git...	Linus Torvalds	4 years

generated by cgit v1.2.3 (git 2.25.1) at 2024-08-12 09:03:30 +0000

// 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/blkdev.h>
#include <linux/memblock.h>	/* for max_pfn/max_low_pfn */
#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-wbt.h"

unsigned long blk_max_low_pfn;
EXPORT_SYMBOL(blk_max_low_pfn);

unsigned long blk_max_pfn;

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_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_dev_sectors = 0;
	lim->chunk_sectors = 0;
	lim->max_write_same_sectors = 0;
	lim->max_write_zeroes_sectors = 0;
	lim->max_discard_sectors = 0;
	lim->max_hw_discard_sectors = 0;
	lim->discard_granularity = 0;
	lim->discard_alignment = 0;
	lim->discard_misaligned = 0;
	lim->logical_block_size = lim->physical_block_size = lim->io_min = 512;
	lim->bounce_pfn = (unsigned long)(BLK_BOUNCE_ANY >> PAGE_SHIFT);
	lim->alignment_offset = 0;
	lim->io_opt = 0;
	lim->misaligned = 0;
	lim->zoned = BLK_ZONED_NONE;
}
EXPORT_SYMBOL(blk_set_default_limits);

/**
 * 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.
 */
void blk_set_stacking_limits(struct queue_limits *lim)
{
	blk_set_default_limits(lim);

	/* 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_same_sectors = UINT_MAX;
	lim->max_write_zeroes_sectors = UINT_MAX;
}
EXPORT_SYMBOL(blk_set_stacking_limits);

/**
 * blk_queue_bounce_limit - set bounce buffer limit for queue
 * @q: the request queue for the device
 * @max_addr: the maximum address the device can handle
 *
 * Description:
 *    Different hardware can have different requirements as to what pages
 *    it can do I/O directly to. A low level driver can call
 *    blk_queue_bounce_limit to have lower memory pages allocated as bounce
 *    buffers for doing I/O to pages residing above @max_addr.
 **/
void blk_queue_bounce_limit(struct request_queue *q, u64 max_addr)
{
	unsigned long b_pfn = max_addr >> PAGE_SHIFT;
	int dma = 0;

	q->bounce_gfp = GFP_NOIO;
#if BITS_PER_LONG == 64
	/*
	 * Assume anything <= 4GB can be handled by IOMMU.  Actually
	 * some IOMMUs can handle everything, but I don't know of a
	 * way to test this here.
	 */
	if (b_pfn < (min_t(u64, 0xffffffffUL, BLK_BOUNCE_HIGH) >> PAGE_SHIFT))
		dma = 1;
	q->limits.bounce_pfn = max(max_low_pfn, b_pfn);
#else
	if (b_pfn < blk_max_low_pfn)
		dma = 1;
	q->limits.bounce_pfn = b_pfn;
#endif
	if (dma) {
		init_emergency_isa_pool();
		q->bounce_gfp = GFP_NOIO | GFP_DMA;
		q->limits.bounce_pfn = b_pfn;
	}
}
EXPORT_SYMBOL(blk_queue_bounce_limit);

/**
 * blk_queue_max_hw_sectors - set max sectors for a request for this queue
 * @q:  the request queue for the device
 * @max_hw_sectors:  max hardware sectors in the usual 512b unit
 *
 * Description:
 *    Enables a low level driver to set a hard upper limit,
 *    max_hw_sectors, on the size of requests.  max_hw_sectors is set by
 *    the device driver based upon the capabilities of the I/O
 *    controller.
 *
 *    max_dev_sectors is a hard limit imposed by the storage device for
 *    READ/WRITE requests. It is set by the disk driver.
 *
 *    max_sectors is a soft limit imposed by the block layer for
 *    filesystem type requests.  This value can be overridden on a
 *    per-device basis in /sys/block/<device>/queue/max_sectors_kb.
 *    The soft limit can not exceed max_hw_sectors.
 **/
void blk_queue_max_hw_sectors(struct request_queue *q, unsigned int max_hw_sectors)
{
	struct queue_limits *limits = &q->limits;
	unsigned int max_sectors;

	if ((max_hw_sectors << 9) < PAGE_SIZE) {
		max_hw_sectors = 1 << (PAGE_SHIFT - 9);
		printk(KERN_INFO "%s: set to minimum %d\n",
		       __func__, max_hw_sectors);
	}

	limits->max_hw_sectors = max_hw_sectors;
	max_sectors = min_not_zero(max_hw_sectors, limits->max_dev_sectors);
	max_sectors = min_t(unsigned int, max_sectors, BLK_DEF_MAX_SECTORS);
	limits->max_sectors = max_sectors;
	q->backing_dev_info->io_pages = max_sectors >> (PAGE_SHIFT - 9);
}
EXPORT_SYMBOL(blk_queue_max_hw_sectors);

/**
 * blk_queue_chunk_sectors - set size of the chunk for this queue
 * @q:  the request queue for the device
 * @chunk_sectors:  chunk sectors in the usual 512b unit
 *
 * Description:
 *    If a driver doesn't want IOs to cross a given chunk size, it can set
 *    this limit and prevent merging across chunks. Note that the chunk size
 *    must currently be a power-of-2 in sectors. Also note that the block
 *    layer must accept a page worth of data at any offset. So if the
 *    crossing of chunks is a hard limitation in the driver, it must still be
 *    prepared to split single page bios.
 **/
void blk_queue_chunk_sectors(struct request_queue *q, unsigned int chunk_sectors)
{
	BUG_ON(!is_power_of_2(chunk_sectors));
	q->limits.chunk_sectors = chunk_sectors;
}
EXPORT_SYMBOL(blk_queue_chunk_sectors);

/**
 * blk_queue_max_discard_sectors - set max sectors for a single discard
 * @q:  the request queue for the device
 * @max_discard_sectors: maximum number of sectors to discard
 **/
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;
}
EXPORT_SYMBOL(blk_queue_max_discard_sectors);

/**
 * blk_queue_max_write_same_sectors - set max sectors for a single write same
 * @q:  the request queue for the device
 * @max_writ