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dm array: introduce cursor api

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More efficient way to iterate an array due to prefetching (makes use of
the new dm_btree_cursor_* api).

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
This commit is contained in:
Joe Thornber
2016-09-15 11:11:42 -04:00
committed by Mike Snitzer
parent 7d111c81fa
commit fdd1315aa5
2 changed files with 119 additions and 0 deletions
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33
drivers/md/persistent-data/dm-array.h
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@@ -182,4 +182,37 @@ int dm_array_walk(struct dm_array_info *info, dm_block_t root,
/*----------------------------------------------------------------*/
/*
* Cursor api.
*
* This lets you iterate through all the entries in an array efficiently
* (it will preload metadata).
*
* I'm using a cursor, rather than a walk function with a callback because
* the cache target needs to iterate both the mapping and hint arrays in
* unison.
*/
struct dm_array_cursor {
struct dm_array_info *info;
struct dm_btree_cursor cursor;
struct dm_block *block;
struct array_block *ab;
unsigned index;
};
int dm_array_cursor_begin(struct dm_array_info *info,
dm_block_t root, struct dm_array_cursor *c);
void dm_array_cursor_end(struct dm_array_cursor *c);
uint32_t dm_array_cursor_index(struct dm_array_cursor *c);
int dm_array_cursor_next(struct dm_array_cursor *c);
/*
* value_le is only valid while the cursor points at the current value.
*/
void dm_array_cursor_get_value(struct dm_array_cursor *c, void **value_le);
/*----------------------------------------------------------------*/
#endif /* _LINUX_DM_ARRAY_H */