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 <[email protected]> --- 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); } /*----------------------------------------------------------------*/ -- dm-devel mailing list [email protected] https://listman.redhat.com/mailman/listinfo/dm-devel
