The struct ro_spine holds pointers to two last blocks when doing read-only
btree walk. The second block is never accessed (note that the function
ro_pop is never called), so we can simplify the code so that it holds
pointer to just one block.
Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx>
---
drivers/md/persistent-data/dm-btree-internal.h | 4 --
drivers/md/persistent-data/dm-btree-spine.c | 41 +++++--------------------
2 files changed, 10 insertions(+), 35 deletions(-)
Index: linux-2.6/drivers/md/persistent-data/dm-btree-internal.h
===================================================================
--- linux-2.6.orig/drivers/md/persistent-data/dm-btree-internal.h 2022-10-10 11:20:17.000000000 +0200
+++ linux-2.6/drivers/md/persistent-data/dm-btree-internal.h 2022-10-10 11:20:55.000000000 +0200
@@ -63,14 +63,12 @@ void unlock_block(struct dm_btree_info *
struct ro_spine {
struct dm_btree_info *info;
- int count;
- struct dm_block *nodes[2];
+ struct dm_block *node;
};
void init_ro_spine(struct ro_spine *s, struct dm_btree_info *info);
void exit_ro_spine(struct ro_spine *s);
int ro_step(struct ro_spine *s, dm_block_t new_child);
-void ro_pop(struct ro_spine *s);
struct btree_node *ro_node(struct ro_spine *s);
struct shadow_spine {
Index: linux-2.6/drivers/md/persistent-data/dm-btree-spine.c
===================================================================
--- linux-2.6.orig/drivers/md/persistent-data/dm-btree-spine.c 2022-10-10 11:20:17.000000000 +0200
+++ linux-2.6/drivers/md/persistent-data/dm-btree-spine.c 2022-10-10 11:20:42.000000000 +0200
@@ -123,52 +123,29 @@ void unlock_block(struct dm_btree_info *
void init_ro_spine(struct ro_spine *s, struct dm_btree_info *info)
{
s->info = info;
- s->count = 0;
- s->nodes[0] = NULL;
- s->nodes[1] = NULL;
+ s->node = NULL;
}
void exit_ro_spine(struct ro_spine *s)
{
- int i;
-
- for (i = 0; i < s->count; i++) {
- unlock_block(s->info, s->nodes[i]);
- }
+ if (s->node)
+ unlock_block(s->info, s->node);
}
int ro_step(struct ro_spine *s, dm_block_t new_child)
{
- int r;
-
- if (s->count == 2) {
- unlock_block(s->info, s->nodes[0]);
- s->nodes[0] = s->nodes[1];
- s->count--;
+ if (s->node) {
+ unlock_block(s->info, s->node);
+ s->node = NULL;
}
- r = bn_read_lock(s->info, new_child, s->nodes + s->count);
- if (!r)
- s->count++;
-
- return r;
-}
-
-void ro_pop(struct ro_spine *s)
-{
- BUG_ON(!s->count);
- --s->count;
- unlock_block(s->info, s->nodes[s->count]);
+ return bn_read_lock(s->info, new_child, &s->node);
}
struct btree_node *ro_node(struct ro_spine *s)
{
- struct dm_block *block;
-
- BUG_ON(!s->count);
- block = s->nodes[s->count - 1];
-
- return dm_block_data(block);
+ BUG_ON(!s->node);
+ return dm_block_data(s->node);
}
/*----------------------------------------------------------------*/
--
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