Commit 40bea431 authored by Mike Snitzer's avatar Mike Snitzer Committed by Alasdair G Kergon
Browse files

dm stripe: expose correct io hints 



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: default avatarMike Snitzer <snitzer@redhat.com>
Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
parent a963a956

drivers/md/dm-stripe.c

+12 −1
Original line number Diff line number Diff line
@@ -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)

drivers/md/dm-table.c

+4 −0
Original line number Diff line number Diff line
@@ -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.

include/linux/device-mapper.h

+4 −0
Original line number Diff line number Diff line
@@ -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;

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