Commit 4c259327 authored by Mike Snitzer's avatar Mike Snitzer Committed by Alasdair G Kergon
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dm table: allow targets to support discards internally 



Permit a target to support discards regardless of whether or not all its
underlying devices do.

Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
parent 139f37f5

drivers/md/dm-table.c

+5 −1
Original line number Diff line number Diff line
@@ -1346,7 +1346,8 @@ bool dm_table_supports_discards(struct dm_table *t) 
		return 0;



	/*

	 * Ensure that at least one underlying device supports discards.

	 * Unless any target used by the table set discards_supported,

	 * require at least one underlying device to support discards.

	 * t->devices includes internal dm devices such as mirror logs

	 * so we need to use iterate_devices here, which targets

	 * supporting discard must provide.
@@ -1354,6 +1355,9 @@ bool dm_table_supports_discards(struct dm_table *t) 
	while (i < dm_table_get_num_targets(t)) {

		ti = dm_table_get_target(t, i++);



		if (ti->discards_supported)

			return 1;



		if (ti->type->iterate_devices &&

		    ti->type->iterate_devices(ti, device_discard_capable, NULL))

			return 1;

include/linux/device-mapper.h

+6 −0
Original line number Diff line number Diff line
@@ -191,6 +191,12 @@ struct dm_target { 


	/* Used to provide an error string from the ctr */

	char *error;



	/*

	 * Set if this target needs to receive discards regardless of

	 * whether or not its underlying devices have support.

	 */

	unsigned discards_supported:1;

};



/* Each target can link one of these into the table */