Add .io_hints to 'struct target_type' to allow the I/O hints portion of
the 'struct queue_limits' to be set by each target. Expose dm-stripe
target's topology I/O hints.
NOTE: This patch makes use of blk_limits_io_min(); which will be
upstream, via the block tree, in the near future.
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
---
diff --git a/drivers/md/dm-stripe.c b/drivers/md/dm-stripe.c
index b240e85..9350566 100644
--- a/drivers/md/dm-stripe.c
+++ b/drivers/md/dm-stripe.c
@@ -328,6 +328,16 @@ 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(chunk_size);
+ limits->io_opt = chunk_size * sc->stripes;
+}
+
static struct target_type stripe_target = {
.name = "striped",
.version = {1, 2, 0},
@@ -338,6 +348,7 @@ 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)
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 5d16d06..5dcdcfe 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -996,6 +996,10 @@ 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.
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index 0d63106..e2b4865 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -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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