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authorMike Snitzer <snitzer@redhat.com>2010-08-12 07:14:08 +0400
committerAlasdair G Kergon <agk@redhat.com>2010-08-12 07:14:08 +0400
commit5ae89a8720c28caf35c4e53711d77df2856c404e (patch)
tree712ddc158309d7ad77e3c19e70f0ae9fafb94446 /drivers/md/dm.h
parent5ebaee6d290279d1df6ce45d6d54de8cfc473273 (diff)
downloadlinux-5ae89a8720c28caf35c4e53711d77df2856c404e.tar.xz
dm: linear support discard
Allow discards to be passed through to linear mappings if at least one underlying device supports it. Discards will be forwarded only to devices that support them. A target that supports discards should set num_discard_requests to indicate how many times each discard request must be submitted to it. Verify table's underlying devices support discards prior to setting the associated DM device as capable of discards (via QUEUE_FLAG_DISCARD). Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Reviewed-by: Joe Thornber <thornber@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Diffstat (limited to 'drivers/md/dm.h')
-rw-r--r--drivers/md/dm.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/md/dm.h b/drivers/md/dm.h
index 0d7b374c5dc2..0c2dd5f4af76 100644
--- a/drivers/md/dm.h
+++ b/drivers/md/dm.h
@@ -61,6 +61,7 @@ int dm_table_any_congested(struct dm_table *t, int bdi_bits);
int dm_table_any_busy_target(struct dm_table *t);
unsigned dm_table_get_type(struct dm_table *t);
bool dm_table_request_based(struct dm_table *t);
+bool dm_table_supports_discards(struct dm_table *t);
int dm_table_alloc_md_mempools(struct dm_table *t);
void dm_table_free_md_mempools(struct dm_table *t);
struct dm_md_mempools *dm_table_get_md_mempools(struct dm_table *t);