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Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-block 

* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
  Make SCSI SG v4 driver enabled by default and remove EXPERIMENTAL dependency, since udev depends on BSG
  block: Update topology documentation
  block: Stack optimal I/O size
  block: Add a wrapper for setting minimum request size without a queue
  block: Make blk_queue_stack_limits use the new stacking interface
This commit is contained in:
Linus Torvalds 2009-08-04 15:39:16 -07:00
parent ae83060026 14d9fa3525
commit 2cf812d732
4 changed files with 78 additions and 50 deletions
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37
Documentation/ABI/testing/sysfs-block
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@ -94,28 +94,37 @@ What: /sys/block/<disk>/queue/physical_block_size
Date: May 2009
Contact: Martin K. Petersen <martin.petersen@oracle.com>
Description:
This is the smallest unit the storage device can write
without resorting to read-modify-write operation. It is
usually the same as the logical block size but may be
bigger. One example is SATA drives with 4KB sectors
that expose a 512-byte logical block size to the
operating system.
This is the smallest unit a physical storage device can
write atomically. It is usually the same as the logical
block size but may be bigger. One example is SATA
drives with 4KB sectors that expose a 512-byte logical
block size to the operating system. For stacked block
devices the physical_block_size variable contains the
maximum physical_block_size of the component devices.
What: /sys/block/<disk>/queue/minimum_io_size
Date: April 2009
Contact: Martin K. Petersen <martin.petersen@oracle.com>
Description:
Storage devices may report a preferred minimum I/O size,
which is the smallest request the device can perform
without incurring a read-modify-write penalty. For disk
drives this is often the physical block size. For RAID
arrays it is often the stripe chunk size.
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.
What: /sys/block/<disk>/queue/optimal_io_size
Date: April 2009
Contact: Martin K. Petersen <martin.petersen@oracle.com>
Description:
Storage devices may report an optimal I/O size, which is
the device's preferred unit of receiving I/O. This is
rarely reported for disk drives. For RAID devices it is
usually the stripe width or the internal block size.
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. If no optimal I/O size is
reported this file contains 0.

11
block/Kconfig
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@ -48,9 +48,9 @@ config LBDAF
If unsure, say Y.
config BLK_DEV_BSG
bool "Block layer SG support v4 (EXPERIMENTAL)"
depends on EXPERIMENTAL
---help---
bool "Block layer SG support v4"
default y
help
Saying Y here will enable generic SG (SCSI generic) v4 support
for any block device.
@ -60,7 +60,10 @@ config BLK_DEV_BSG
protocols (e.g. Task Management Functions and SMP in Serial
Attached SCSI).
If unsure, say N.
This option is required by recent UDEV versions to properly
access device serial numbers, etc.
If unsure, say Y.
config BLK_DEV_INTEGRITY
bool "Block layer data integrity support"

79
block/blk-settings.c
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@ -7,6 +7,7 @@
#include <linux/bio.h>
#include <linux/blkdev.h>
#include <linux/bootmem.h> /* for max_pfn/max_low_pfn */
#include <linux/gcd.h>
#include "blk.h"
@ -384,8 +385,8 @@ void blk_queue_alignment_offset(struct request_queue *q, unsigned int offset)
EXPORT_SYMBOL(blk_queue_alignment_offset);
/**
* blk_queue_io_min - set minimum request size for the queue
* @q: the request queue for the device
* blk_limits_io_min - set minimum request size for a device
* @limits: the queue limits
* @min: smallest I/O size in bytes
*
* Description:
@ -394,15 +395,35 @@ EXPORT_SYMBOL(blk_queue_alignment_offset);
* 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)
{
q->limits.io_min = min;
if (q->limits.io_min < q->limits.logical_block_size)
q->limits.io_min = q->limits.logical_block_size;
if (q->limits.io_min < q->limits.physical_block_size)
q->limits.io_min = q->limits.physical_block_size;
blk_limits_io_min(&q->limits, min);
}
EXPORT_SYMBOL(blk_queue_io_min);
@ -412,8 +433,12 @@ EXPORT_SYMBOL(blk_queue_io_min);
* @opt: optimal request size in bytes
*
* Description:
* Drivers can call this function to set the preferred I/O request
* size for devices that report such a value.
* 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)
{
@ -433,27 +458,7 @@ EXPORT_SYMBOL(blk_queue_io_opt);
**/
void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b)
{
/* zero is "infinity" */
t->limits.max_sectors = min_not_zero(queue_max_sectors(t),
queue_max_sectors(b));
t->limits.max_hw_sectors = min_not_zero(queue_max_hw_sectors(t),
queue_max_hw_sectors(b));
t->limits.seg_boundary_mask = min_not_zero(queue_segment_boundary(t),
queue_segment_boundary(b));
t->limits.max_phys_segments = min_not_zero(queue_max_phys_segments(t),
queue_max_phys_segments(b));
t->limits.max_hw_segments = min_not_zero(queue_max_hw_segments(t),
queue_max_hw_segments(b));
t->limits.max_segment_size = min_not_zero(queue_max_segment_size(t),
queue_max_segment_size(b));
t->limits.logical_block_size = max(queue_logical_block_size(t),
queue_logical_block_size(b));
blk_stack_limits(&t->limits, &b->limits, 0);
if (!t->queue_lock)
WARN_ON_ONCE(1);
@ -523,6 +528,16 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
return -1;
}
/* Find lcm() of optimal I/O size */
if (t->io_opt && b->io_opt)
t->io_opt = (t->io_opt * b->io_opt) / gcd(t->io_opt, b->io_opt);
else if (b->io_opt)
t->io_opt = b->io_opt;
/* Verify that optimal I/O size is a multiple of io_min */
if (t->io_min && t->io_opt % t->io_min)
return -1;
return 0;
}
EXPORT_SYMBOL(blk_stack_limits);

1
include/linux/blkdev.h
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@ -913,6 +913,7 @@ extern void blk_queue_logical_block_size(struct request_queue *, unsigned short)
extern void blk_queue_physical_block_size(struct request_queue *, unsigned short);
extern void blk_queue_alignment_offset(struct request_queue *q,
unsigned int alignment);
extern void blk_limits_io_min(struct queue_limits *limits, unsigned int min);
extern void blk_queue_io_min(struct request_queue *q, unsigned int min);
extern void blk_queue_io_opt(struct request_queue *q, unsigned int opt);
extern void blk_set_default_limits(struct queue_limits *lim);