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dm stripe: expose correct io hints

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Set sensible I/O hints for striped DM devices in the topology
infrastructure added for 2.6.31 for userspace tools to
obtain via sysfs.

Add .io_hints to 'struct target_type' to allow the I/O hints portion
(io_min and io_opt) of the 'struct queue_limits' to be set by each
target and implement this for dm-stripe.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
This commit is contained in:
Mike Snitzer 2009-09-04 20:40:25 +01:00 committed by Alasdair G Kergon
parent a963a95622
commit 40bea43127
3 changed files with 20 additions and 1 deletions
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13
drivers/md/dm-stripe.c
View file

@ -329,9 +329,19 @@ static int stripe_iterate_devices(struct dm_target *ti,
return ret;
}
static void stripe_io_hints(struct dm_target *ti,
struct queue_limits *limits)
{
struct stripe_c *sc = ti->private;
unsigned chunk_size = (sc->chunk_mask + 1) << 9;
blk_limits_io_min(limits, chunk_size);
limits->io_opt = chunk_size * sc->stripes;
}
static struct target_type stripe_target = {
.name = "striped",
.version = {1, 2, 0},
.version = {1, 3, 0},
.module = THIS_MODULE,
.ctr = stripe_ctr,
.dtr = stripe_dtr,
@ -339,6 +349,7 @@ static struct target_type stripe_target = {
.end_io = stripe_end_io,
.status = stripe_status,
.iterate_devices = stripe_iterate_devices,
.io_hints = stripe_io_hints,
};
int __init dm_stripe_init(void)

4
drivers/md/dm-table.c
View file

@ -1007,6 +1007,10 @@ int dm_calculate_queue_limits(struct dm_table *table,
ti->type->iterate_devices(ti, dm_set_device_limits,
&ti_limits);
/* Set I/O hints portion of queue limits */
if (ti->type->io_hints)
ti->type->io_hints(ti, &ti_limits);
/*
* Check each device area is consistent with the target's
* overall queue limits.

4
include/linux/device-mapper.h
View file

@ -91,6 +91,9 @@ typedef int (*dm_iterate_devices_fn) (struct dm_target *ti,
iterate_devices_callout_fn fn,
void *data);
typedef void (*dm_io_hints_fn) (struct dm_target *ti,
struct queue_limits *limits);
/*
* Returns:
* 0: The target can handle the next I/O immediately.
@ -151,6 +154,7 @@ struct target_type {
dm_merge_fn merge;
dm_busy_fn busy;
dm_iterate_devices_fn iterate_devices;
dm_io_hints_fn io_hints;
/* For internal device-mapper use. */
struct list_head list;