Since all tables are now stored together, it is possible to obtain
the position of a particular table directly from its address, so the
operation becomes O(1).
Signed-off-by: Alberto Garcia be...@igalia.com
---
block/qcow2-cache.c | 32 +++-
1 file changed, 15 insertions(+), 17 deletions(-)
diff --git a/block/qcow2-cache.c b/block/qcow2-cache.c
index f0dfb69..6e78c8f 100644
--- a/block/qcow2-cache.c
+++ b/block/qcow2-cache.c
@@ -49,6 +49,16 @@ static inline void
*qcow2_cache_get_table_addr(BlockDriverState *bs,
return (uint8_t *) c-table_array + (size_t) table * s-cluster_size;
}
+static inline int qcow2_cache_get_table_idx(BlockDriverState *bs,
+ Qcow2Cache *c, void *table)
+{
+BDRVQcowState *s = bs-opaque;
+ptrdiff_t table_offset = (uint8_t *) table - (uint8_t *) c-table_array;
+int idx = table_offset / s-cluster_size;
+assert(idx = 0 idx c-size table_offset % s-cluster_size == 0);
+return idx;
+}
+
Qcow2Cache *qcow2_cache_create(BlockDriverState *bs, int num_tables)
{
BDRVQcowState *s = bs-opaque;
@@ -337,16 +347,12 @@ int qcow2_cache_get_empty(BlockDriverState *bs,
Qcow2Cache *c, uint64_t offset,
int qcow2_cache_put(BlockDriverState *bs, Qcow2Cache *c, void **table)
{
-int i;
+int i = qcow2_cache_get_table_idx(bs, c, *table);
-for (i = 0; i c-size; i++) {
-if (qcow2_cache_get_table_addr(bs, c, i) == *table) {
-goto found;
-}
+if (c-entries[i].offset == 0) {
+return -ENOENT;
}
-return -ENOENT;
-found:
c-entries[i].ref--;
*table = NULL;
@@ -357,15 +363,7 @@ found:
void qcow2_cache_entry_mark_dirty(BlockDriverState *bs, Qcow2Cache *c,
void *table)
{
-int i;
-
-for (i = 0; i c-size; i++) {
-if (qcow2_cache_get_table_addr(bs, c, i) == table) {
-goto found;
-}
-}
-abort();
-
-found:
+int i = qcow2_cache_get_table_idx(bs, c, table);
+assert(c-entries[i].offset != 0);
c-entries[i].dirty = true;
}
--
2.1.4
