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[PATCH] dm: extract device limit setting 

Separate the setting of device I/O limits from dm_get_device().  dm-loop will
use this.

Signed-off-by: Bryn Reeves <breeves@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Bryn Reeves 2006-10-03 01:15:42 -07:00 committed by Linus Torvalds
parent 9faf400f7e
commit 3cb4021453
2 changed files with 53 additions and 43 deletions
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91
drivers/md/dm-table.c
View File

@ -522,56 +522,61 @@ static int __table_get_device(struct dm_table *t, struct dm_target *ti,
return 0;
}
void dm_set_device_limits(struct dm_target *ti, struct block_device *bdev)
{
request_queue_t *q = bdev_get_queue(bdev);
struct io_restrictions *rs = &ti->limits;
/*
* Combine the device limits low.
*
* FIXME: if we move an io_restriction struct
* into q this would just be a call to
* combine_restrictions_low()
*/
rs->max_sectors =
min_not_zero(rs->max_sectors, q->max_sectors);
/* FIXME: Device-Mapper on top of RAID-0 breaks because DM
* currently doesn't honor MD's merge_bvec_fn routine.
* In this case, we'll force DM to use PAGE_SIZE or
* smaller I/O, just to be safe. A better fix is in the
* works, but add this for the time being so it will at
* least operate correctly.
*/
if (q->merge_bvec_fn)
rs->max_sectors =
min_not_zero(rs->max_sectors,
(unsigned int) (PAGE_SIZE >> 9));
rs->max_phys_segments =
min_not_zero(rs->max_phys_segments,
q->max_phys_segments);
rs->max_hw_segments =
min_not_zero(rs->max_hw_segments, q->max_hw_segments);
rs->hardsect_size = max(rs->hardsect_size, q->hardsect_size);
rs->max_segment_size =
min_not_zero(rs->max_segment_size, q->max_segment_size);
rs->seg_boundary_mask =
min_not_zero(rs->seg_boundary_mask,
q->seg_boundary_mask);
rs->no_cluster |= !test_bit(QUEUE_FLAG_CLUSTER, &q->queue_flags);
}
EXPORT_SYMBOL_GPL(dm_set_device_limits);
int dm_get_device(struct dm_target *ti, const char *path, sector_t start,
sector_t len, int mode, struct dm_dev **result)
{
int r = __table_get_device(ti->table, ti, path,
start, len, mode, result);
if (!r) {
request_queue_t *q = bdev_get_queue((*result)->bdev);
struct io_restrictions *rs = &ti->limits;
/*
* Combine the device limits low.
*
* FIXME: if we move an io_restriction struct
* into q this would just be a call to
* combine_restrictions_low()
*/
rs->max_sectors =
min_not_zero(rs->max_sectors, q->max_sectors);
/* FIXME: Device-Mapper on top of RAID-0 breaks because DM
* currently doesn't honor MD's merge_bvec_fn routine.
* In this case, we'll force DM to use PAGE_SIZE or
* smaller I/O, just to be safe. A better fix is in the
* works, but add this for the time being so it will at
* least operate correctly.
*/
if (q->merge_bvec_fn)
rs->max_sectors =
min_not_zero(rs->max_sectors,
(unsigned int) (PAGE_SIZE >> 9));
rs->max_phys_segments =
min_not_zero(rs->max_phys_segments,
q->max_phys_segments);
rs->max_hw_segments =
min_not_zero(rs->max_hw_segments, q->max_hw_segments);
rs->hardsect_size = max(rs->hardsect_size, q->hardsect_size);
rs->max_segment_size =
min_not_zero(rs->max_segment_size, q->max_segment_size);
rs->seg_boundary_mask =
min_not_zero(rs->seg_boundary_mask,
q->seg_boundary_mask);
rs->no_cluster |= !test_bit(QUEUE_FLAG_CLUSTER, &q->queue_flags);
}
if (!r)
dm_set_device_limits(ti, (*result)->bdev);
return r;
}

5
include/linux/device-mapper.h
View File

@ -71,6 +71,11 @@ typedef int (*dm_ioctl_fn) (struct dm_target *ti, struct inode *inode,
void dm_error(const char *message);
/*
* Combine device limits.
*/
void dm_set_device_limits(struct dm_target *ti, struct block_device *bdev);
/*
* Constructors should call these functions to ensure destination devices
* are opened/closed correctly.