OSCL-LXR linux-6.0.1/​block/​blk-settings.c	Source navigation Diff markup Identifier search General search
	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // 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/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-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_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_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 = 0;
     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 = BLK_ZONED_NONE;
     lim->zone_write_granularity = 0;
 }
 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_zeroes_sectors = UINT_MAX;
     lim->max_zone_append_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
  * @bounce: bounce limit to enforce
  *
  * Description:
  *    Force bouncing for ISA DMA ranges or highmem.
  *
  *    DEPRECATED, don't use in new code.
  **/
 void blk_queue_bounce_limit(struct request_queue *q, enum blk_bounce bounce)
 {
     q->limits.bounce = bounce;
 }
 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);
     }
 
     max_hw_sectors = round_down(max_hw_sectors,
                     limits->logical_block_size >> SECTOR_SHIFT);
     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);
     max_sectors = round_down(max_sectors,
                  limits->logical_block_size >> SECTOR_SHIFT);
     limits->max_sectors = max_sectors;
 
     if (!q->disk)
         return;
     q->disk->bdi->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 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)
 {
     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_secure_erase_sectors - set max sectors for a secure erase
  * @q:  the request queue for the device
  * @max_sectors: maximum number of sectors to secure_erase
  **/
 void blk_queue_max_secure_erase_sectors(struct request_queue *q,
         unsigned int max_sectors)
 {
     q->limits.max_secure_erase_sectors = max_sectors;
 }
 EXPORT_SYMBOL(blk_queue_max_secure_erase_sectors);
 
 /**
  * blk_queue_max_write_zeroes_sectors - set max sectors for a single
  *                                      write zeroes
  * @q:  the request queue for the device
  * @max_write_zeroes_sectors: maximum number of sectors to write per command
  **/
 void blk_queue_max_write_zeroes_sectors(struct request_queue *q,
         unsigned int max_write_zeroes_sectors)
 {
     q->limits.max_write_zeroes_sectors = max_write_zeroes_sectors;
 }
 EXPORT_SYMBOL(blk_queue_max_write_zeroes_sectors);
 
 /**
  * blk_queue_max_zone_append_sectors - set max sectors for a single zone append
  * @q:  the request queue for the device
  * @max_zone_append_sectors: maximum number of sectors to write per command
  **/
 void blk_queue_max_zone_append_sectors(struct request_queue *q,
         unsigned int max_zone_append_sectors)
 {
     unsigned int max_sectors;
 
     if (WARN_ON(!blk_queue_is_zoned(q)))
         return;
 
     max_sectors = min(q->limits.max_hw_sectors, max_zone_append_sectors);
     max_sectors = min(q->limits.chunk_sectors, max_sectors);
 
     /*
      * Signal eventual driver bugs resulting in the max_zone_append sectors limit
      * being 0 due to a 0 argument, the chunk_sectors limit (zone size) not set,
      * or the max_hw_sectors limit not set.
      */
     WARN_ON(!max_sectors);
 
     q->limits.max_zone_append_sectors = max_sectors;
 }
 EXPORT_SYMBOL_GPL(blk_queue_max_zone_append_sectors);
 
 /**
  * blk_queue_max_segments - set max hw segments for a request for this queue
  * @q:  the request queue for the device
  * @max_segments:  max number of segments
  *
  * Description:
  *    Enables a low level driver to set an upper limit on the number of
  *    hw data segments in a request.
  **/
 void blk_queue_max_segments(struct request_queue *q, unsigned short max_segments)
 {
     if (!max_segments) {
         max_segments = 1;
         printk(KERN_INFO "%s: set to minimum %d\n",
                __func__, max_segments);
     }
 
     q->limits.max_segments = max_segments;
 }
 EXPORT_SYMBOL(blk_queue_max_segments);
 
 /**
  * blk_queue_max_discard_segments - set max segments for discard requests
  * @q:  the request queue for the device
  * @max_segments:  max number of segments
  *
  * Description:
  *    Enables a low level driver to set an upper limit on the number of
  *    segments in a discard request.
  **/
 void blk_queue_max_discard_segments(struct request_queue *q,
         unsigned short max_segments)
 {
     q->limits.max_discard_segments = max_segments;
 }
 EXPORT_SYMBOL_GPL(blk_queue_max_discard_segments);
 
 /**
  * blk_queue_max_segment_size - set max segment size for blk_rq_map_sg
  * @q:  the request queue for the device
  * @max_size:  max size of segment in bytes
  *
  * Description:
  *    Enables a low level driver to set an upper limit on the size of a
  *    coalesced segment
  **/
 void blk_queue_max_segment_size(struct request_queue *q, unsigned int max_size)
 {
     if (max_size < PAGE_SIZE) {
         max_size = PAGE_SIZE;
         printk(KERN_INFO "%s: set to minimum %d\n",
                __func__, max_size);
     }
 
     /* see blk_queue_virt_boundary() for the explanation */
     WARN_ON_ONCE(q->limits.virt_boundary_mask);
 
     q->limits.max_segment_size = max_size;
 }
 EXPORT_SYMBOL(blk_queue_max_segment_size);
 
 /**
  * blk_queue_logical_block_size - set logical block size for the queue
  * @q:  the request queue for the device
  * @size:  the logical block size, in bytes
  *
  * Description:
  *   This should be set to the lowest possible block size that the
  *   storage device can address.  The default of 512 covers most
  *   hardware.
  **/
 void blk_queue_logical_block_size(struct request_queue *q, unsigned int size)
 {
     struct queue_limits *limits = &q->limits;
 
     limits->logical_block_size = size;
 
     if (limits->physical_block_size < size)
         limits->physical_block_size = size;
 
     if (limits->io_min < limits->physical_block_size)
         limits->io_min = limits->physical_block_size;
 
     limits->max_hw_sectors =
         round_down(limits->max_hw_sectors, size >> SECTOR_SHIFT);
     limits->max_sectors =
         round_down(limits->max_sectors, size >> SECTOR_SHIFT);
 }
 EXPORT_SYMBOL(blk_queue_logical_block_size);
 
 /**
  * blk_queue_physical_block_size - set physical block size for the queue
  * @q:  the request queue for the device
  * @size:  the physical block size, in bytes
  *
  * Description:
  *   This should be set to the lowest possible sector size that the
  *   hardware can operate on without reverting to read-modify-write
  *   operations.
  */
 void blk_queue_physical_block_size(struct request_queue *q, unsigned int size)
 {
     q->limits.physical_block_size = size;
 
     if (q->limits.physical_block_size < q->limits.logical_block_size)
         q->limits.physical_block_size = q->limits.logical_block_size;
 
     if (q->limits.io_min < q->limits.physical_block_size)
         q->limits.io_min = q->limits.physical_block_size;
 }
 EXPORT_SYMBOL(blk_queue_physical_block_size);
 
 /**
  * blk_queue_zone_write_granularity - set zone write granularity for the queue
  * @q:  the request queue for the zoned device
  * @size:  the zone write granularity size, in bytes
  *
  * Description:
  *   This should be set to the lowest possible size allowing to write in
  *   sequential zones of a zoned block device.
  */
 void blk_queue_zone_write_granularity(struct request_queue *q,
                       unsigned int size)
 {
     if (WARN_ON_ONCE(!blk_queue_is_zoned(q)))
         return;
 
     q->limits.zone_write_granularity = size;
 
     if (q->limits.zone_write_granularity < q->limits.logical_block_size)
         q->limits.zone_write_granularity = q->limits.logical_block_size;
 }
 EXPORT_SYMBOL_GPL(blk_queue_zone_write_granularity);
 
 /**
  * blk_queue_alignment_offset - set physical block alignment offset
  * @q:  the request queue for the device
  * @offset: alignment offset in bytes
  *
  * Description:
  *   Some devices are naturally misaligned to compensate for things like
  *   the legacy DOS partition table 63-sector offset.  Low-level drivers
  *   should call this function for devices whose first sector is not
  *   naturally aligned.
  */
 void blk_queue_alignment_offset(struct request_queue *q, unsigned int offset)
 {
     q->limits.alignment_offset =
         offset & (q->limits.physical_block_size - 1);
     q->limits.misaligned = 0;
 }
 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);
 }
 EXPORT_SYMBOL_GPL(disk_update_readahead);
 
 /**
  * blk_limits_io_min - set minimum request size for a device
  * @limits: the queue limits
  * @min:  smallest I/O size in bytes
  *
  * Description:
  *   Some devices have an internal block size bigger than the reported
  *   hardware sector size.  This function can be used to signal the
  *   smallest I/O the device can perform without incurring a performance
  *   penalty.
  */
 void blk_limits_io_min(struct queue_limits *limits, unsigned int min)
 {
     limits->io_min = min;
 
     if (limits->io_min < limits->logical_block_size)
         limits->io_min = limits->logical_block_size;
 
     if (limits->io_min < limits->physical_block_size)
         limits->io_min = limits->physical_block_size;
 }
 EXPORT_SYMBOL(blk_limits_io_min);
 
 /**
  * blk_queue_io_min - set minimum request size for the queue
  * @q:  the request queue for the device
  * @min:  smallest I/O size in bytes
  *
  * Description:
  *   Storage devices may report a granularity or preferred minimum I/O
  *   size which is the smallest request the device can perform without
  *   incurring a performance penalty.  For disk drives this is often the
  *   physical block size.  For RAID arrays it is often the stripe chunk
  *   size.  A properly aligned multiple of minimum_io_size is the
  *   preferred request size for workloads where a high number of I/O
  *   operations is desired.
  */
 void blk_queue_io_min(struct request_queue *q, unsigned int min)
 {
     blk_limits_io_min(&q->limits, min);
 }
 EXPORT_SYMBOL(blk_queue_io_min);
 
 /**
  * blk_limits_io_opt - set optimal request size for a device
  * @limits: the queue limits
  * @opt:  smallest I/O size in bytes
  *
  * Description:
  *   Storage devices may report an optimal I/O size, which is the
  *   device's preferred unit for sustained I/O.  This is rarely reported
  *   for disk drives.  For RAID arrays it is usually the stripe width or
  *   the internal track size.  A properly aligned multiple of
  *   optimal_io_size is the preferred request size for workloads where
  *   sustained throughput is desired.
  */
 void blk_limits_io_opt(struct queue_limits *limits, unsigned int opt)
 {
     limits->io_opt = opt;
 }
 EXPORT_SYMBOL(blk_limits_io_opt);
 
 /**
  * blk_queue_io_opt - set optimal request size for the queue
  * @q:  the request queue for the device
  * @opt:  optimal request size in bytes
  *
  * Description:
  *   Storage devices may report an optimal I/O size, which is the
  *   device's preferred unit for sustained I/O.  This is rarely reported
  *   for disk drives.  For RAID arrays it is usually the stripe width or
  *   the internal track size.  A properly aligned multiple of
  *   optimal_io_size is the preferred request size for workloads where
  *   sustained throughput is desired.
  */
 void blk_queue_io_opt(struct request_queue *q, unsigned int opt)
 {
     blk_limits_io_opt(&q->limits, opt);
     if (!q->disk)
         return;
     q->disk->bdi->ra_pages =
         max(queue_io_opt(q) * 2 / PAGE_SIZE, VM_READAHEAD_PAGES);
 }
 EXPORT_SYMBOL(blk_queue_io_opt);
 
 static int queue_limit_alignment_offset(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(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;
     if (!granularity)
         return 0;
 
     /* 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;
 }
 
 /**
  * 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, ret = 0;
 
     t->max_sectors = min_not_zero(t->max_sectors, b->max_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_zone_append_sectors = min(t->max_zone_append_sectors,
                     b->max_zone_append_sectors);
     t->bounce = max(t->bounce, b->bounce);
 
     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);
 
     t->misaligned |= b->misaligned;
 
     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->misaligned = 1;
             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);
 
     /* 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->misaligned = 1;
         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->misaligned = 1;
         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->misaligned = 1;
         ret = -1;
     }
 
     /* chunk_sectors a multiple of the physical block size? */
     if ((t->chunk_sectors << 9) & (t->physical_block_size - 1)) {
         t->chunk_sectors = 0;
         t->misaligned = 1;
         ret = -1;
     }
 
     t->raid_partial_stripes_expensive =
         max(t->raid_partial_stripes_expensive,
             b->raid_partial_stripes_expensive);
 
     /* 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->misaligned = 1;
         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);
 
         if (t->discard_granularity != 0 &&
             t->discard_alignment != alignment) {
             top = t->discard_granularity + t->discard_alignment;
             bottom = b->discard_granularity + alignment;
 
             /* Verify that top and bottom intervals line up */
             if ((max(top, bottom) % min(top, bottom)) != 0)
                 t->discard_misaligned = 1;
         }
 
         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);
     t->zoned = max(t->zoned, b->zoned);
     return ret;
 }
 EXPORT_SYMBOL(blk_stack_limits);
 
 /**
  * disk_stack_limits - adjust queue limits for stacked drivers
  * @disk:  MD/DM gendisk (top)
  * @bdev:  the underlying block device (bottom)
  * @offset:  offset to beginning of data within component device
  *
  * Description:
  *    Merges the limits for a top level gendisk and a bottom level
  *    block_device.
  */
 void disk_stack_limits(struct gendisk *disk, struct block_device *bdev,
                sector_t offset)
 {
     struct request_queue *t = disk->queue;
 
     if (blk_stack_limits(&t->limits, &bdev_get_queue(bdev)->limits,
             get_start_sect(bdev) + (offset >> 9)) < 0)
         pr_notice("%s: Warning: Device %pg is misaligned\n",
             disk->disk_name, bdev);
 
     disk_update_readahead(disk);
 }
 EXPORT_SYMBOL(disk_stack_limits);
 
 /**
  * blk_queue_update_dma_pad - update pad mask
  * @q:     the request queue for the device
  * @mask:  pad mask
  *
  * Update dma pad mask.
  *
  * Appending pad buffer to a request modifies the last entry of a
  * scatter list such that it includes the pad buffer.
  **/
 void blk_queue_update_dma_pad(struct request_queue *q, unsigned int mask)
 {
     if (mask > q->dma_pad_mask)
         q->dma_pad_mask = mask;
 }
 EXPORT_SYMBOL(blk_queue_update_dma_pad);
 
 /**
  * blk_queue_segment_boundary - set boundary rules for segment merging
  * @q:  the request queue for the device
  * @mask:  the memory boundary mask
  **/
 void blk_queue_segment_boundary(struct request_queue *q, unsigned long mask)
 {
     if (mask < PAGE_SIZE - 1) {
         mask = PAGE_SIZE - 1;
         printk(KERN_INFO "%s: set to minimum %lx\n",
                __func__, mask);
     }
 
     q->limits.seg_boundary_mask = mask;
 }
 EXPORT_SYMBOL(blk_queue_segment_boundary);
 
 /**
  * blk_queue_virt_boundary - set boundary rules for bio merging
  * @q:  the request queue for the device
  * @mask:  the memory boundary mask
  **/
 void blk_queue_virt_boundary(struct request_queue *q, unsigned long mask)
 {
     q->limits.virt_boundary_mask = mask;
 
     /*
      * 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 idential to the Linux PAGE_SIZE).  Because
      * of that they are not limited by our notion of "segment size".
      */
     if (mask)
         q->limits.max_segment_size = UINT_MAX;
 }
 EXPORT_SYMBOL(blk_queue_virt_boundary);
 
 /**
  * blk_queue_dma_alignment - set dma length and memory alignment
  * @q:     the request queue for the device
  * @mask:  alignment mask
  *
  * description:
  *    set required memory and length alignment for direct dma transactions.
  *    this is used when building direct io requests for the queue.
  *
  **/
 void blk_queue_dma_alignment(struct request_queue *q, int mask)
 {
     q->dma_alignment = mask;
 }
 EXPORT_SYMBOL(blk_queue_dma_alignment);
 
 /**
  * blk_queue_update_dma_alignment - update dma length and memory alignment
  * @q:     the request queue for the device
  * @mask:  alignment mask
  *
  * description:
  *    update required memory and length alignment for direct dma transactions.
  *    If the requested alignment is larger than the current alignment, then
  *    the current queue alignment is updated to the new value, otherwise it
  *    is left alone.  The design of this is to allow multiple objects
  *    (driver, device, transport etc) to set their respective
  *    alignments without having them interfere.
  *
  **/
 void blk_queue_update_dma_alignment(struct request_queue *q, int mask)
 {
     BUG_ON(mask > PAGE_SIZE);
 
     if (mask > q->dma_alignment)
         q->dma_alignment = mask;
 }
 EXPORT_SYMBOL(blk_queue_update_dma_alignment);
 
 /**
  * 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);
 
 /**
  * blk_queue_write_cache - configure queue's write cache
  * @q:      the request queue for the device
  * @wc:     write back cache on or off
  * @fua:    device supports FUA writes, if true
  *
  * Tell the block layer about the write cache of @q.
  */
 void blk_queue_write_cache(struct request_queue *q, bool wc, bool fua)
 {
     if (wc)
         blk_queue_flag_set(QUEUE_FLAG_WC, q);
     else
         blk_queue_flag_clear(QUEUE_FLAG_WC, q);
     if (fua)
         blk_queue_flag_set(QUEUE_FLAG_FUA, q);
     else
         blk_queue_flag_clear(QUEUE_FLAG_FUA, q);
 
     wbt_set_write_cache(q, test_bit(QUEUE_FLAG_WC, &q->queue_flags));
 }
 EXPORT_SYMBOL_GPL(blk_queue_write_cache);
 
 /**
  * blk_queue_required_elevator_features - Set a queue required elevator features
  * @q:      the request queue for the target device
  * @features:   Required elevator features OR'ed together
  *
  * Tell the block layer that for the device controlled through @q, only the
  * only elevators that can be used are those that implement at least the set of
  * features specified by @features.
  */
 void blk_queue_required_elevator_features(struct request_queue *q,
                       unsigned int features)
 {
     q->required_elevator_features = features;
 }
 EXPORT_SYMBOL_GPL(blk_queue_required_elevator_features);
 
 /**
  * blk_queue_can_use_dma_map_merging - configure queue for merging segments.
  * @q:      the request queue for the device
  * @dev:    the device pointer for dma
  *
  * Tell the block layer about merging the segments by dma map of @q.
  */
 bool blk_queue_can_use_dma_map_merging(struct request_queue *q,
                        struct device *dev)
 {
     unsigned long boundary = dma_get_merge_boundary(dev);
 
     if (!boundary)
         return false;
 
     /* No need to update max_segment_size. see blk_queue_virt_boundary() */
     blk_queue_virt_boundary(q, boundary);
 
     return true;
 }
 EXPORT_SYMBOL_GPL(blk_queue_can_use_dma_map_merging);
 
 static bool disk_has_partitions(struct gendisk *disk)
 {
     unsigned long idx;
     struct block_device *part;
     bool ret = false;
 
     rcu_read_lock();
     xa_for_each(&disk->part_tbl, idx, part) {
         if (bdev_is_partition(part)) {
             ret = true;
             break;
         }
     }
     rcu_read_unlock();
 
     return ret;
 }
 
 /**
  * disk_set_zoned - configure the zoned model for a disk
  * @disk:   the gendisk of the queue to configure
  * @model:  the zoned model to set
  *
  * Set the zoned model of @disk to @model.
  *
  * When @model is BLK_ZONED_HM (host managed), this should be called only
  * if zoned block device support is enabled (CONFIG_BLK_DEV_ZONED option).
  * If @model specifies BLK_ZONED_HA (host aware), the effective model used
  * depends on CONFIG_BLK_DEV_ZONED settings and on the existence of partitions
  * on the disk.
  */
 void disk_set_zoned(struct gendisk *disk, enum blk_zoned_model model)
 {
     struct request_queue *q = disk->queue;
 
     switch (model) {
     case BLK_ZONED_HM:
         /*
          * Host managed devices are supported only if
          * CONFIG_BLK_DEV_ZONED is enabled.
          */
         WARN_ON_ONCE(!IS_ENABLED(CONFIG_BLK_DEV_ZONED));
         break;
     case BLK_ZONED_HA:
         /*
          * Host aware devices can be treated either as regular block
          * devices (similar to drive managed devices) or as zoned block
          * devices to take advantage of the zone command set, similarly
          * to host managed devices. We try the latter if there are no
          * partitions and zoned block device support is enabled, else
          * we do nothing special as far as the block layer is concerned.
          */
         if (!IS_ENABLED(CONFIG_BLK_DEV_ZONED) ||
             disk_has_partitions(disk))
             model = BLK_ZONED_NONE;
         break;
     case BLK_ZONED_NONE:
     default:
         if (WARN_ON_ONCE(model != BLK_ZONED_NONE))
             model = BLK_ZONED_NONE;
         break;
     }
 
     q->limits.zoned = model;
     if (model != BLK_ZONED_NONE) {
         /*
          * Set the zone write granularity to the device logical block
          * size by default. The driver can change this value if needed.
          */
         blk_queue_zone_write_granularity(q,
                         queue_logical_block_size(q));
     } else {
         disk_clear_zone_settings(disk);
     }
 }
 EXPORT_SYMBOL_GPL(disk_set_zoned);
 
 int bdev_alignment_offset(struct block_device *bdev)
 {
     struct request_queue *q = bdev_get_queue(bdev);
 
     if (q->limits.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);

This page was automatically generated by the 2.1.0 LXR engine. The LXR team