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authorJoe Thornber <ejt@redhat.com>2014-09-17 10:17:39 +0100
committerMike Snitzer <snitzer@redhat.com>2014-11-10 15:25:30 -0500
commit5f274d886598c9fd26d2499bf3f68306f170e9db (patch)
treeaf0ded19382c65e832ea51e2b01efb40581c81dd /drivers/md/dm-bio-prison.h
parentf1afb36a6102b52949c2c6d8eb250eddcce3fc5f (diff)
downloadlinux-5f274d886598c9fd26d2499bf3f68306f170e9db.tar.bz2
dm bio prison: introduce support for locking ranges of blocks
Ranges will be placed in the same cell if they overlap. Range locking is a prerequisite for more efficient multi-block discard support in both the cache and thin-provisioning targets. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'drivers/md/dm-bio-prison.h')
-rw-r--r--drivers/md/dm-bio-prison.h12
1 files changed, 8 insertions, 4 deletions
diff --git a/drivers/md/dm-bio-prison.h b/drivers/md/dm-bio-prison.h
index b03988667740..74cf01144b1f 100644
--- a/drivers/md/dm-bio-prison.h
+++ b/drivers/md/dm-bio-prison.h
@@ -23,11 +23,14 @@
*/
struct dm_bio_prison;
-/* FIXME: this needs to be more abstract */
+/*
+ * Keys define a range of blocks within either a virtual or physical
+ * device.
+ */
struct dm_cell_key {
int virtual;
dm_thin_id dev;
- dm_block_t block;
+ dm_block_t block_begin, block_end;
};
/*
@@ -59,7 +62,7 @@ void dm_bio_prison_free_cell(struct dm_bio_prison *prison,
struct dm_bio_prison_cell *cell);
/*
- * Creates, or retrieves a cell for the given key.
+ * Creates, or retrieves a cell that overlaps the given key.
*
* Returns 1 if pre-existing cell returned, zero if new cell created using
* @cell_prealloc.
@@ -70,7 +73,8 @@ int dm_get_cell(struct dm_bio_prison *prison,
struct dm_bio_prison_cell **cell_result);
/*
- * An atomic op that combines retrieving a cell, and adding a bio to it.
+ * An atomic op that combines retrieving or creating a cell, and adding a
+ * bio to it.
*
* Returns 1 if the cell was already held, 0 if @inmate is the new holder.
*/