dm cache: avoid preallocation if no work in writeback_some_dirty_blocks()
Refactor writeback_some_dirty_blocks() to avoid prealloc_data_structs()
if the policy doesn't have any dirty blocks ready for writeback.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c
index c8a160b..408dd27 100644
--- a/drivers/md/dm-cache-target.c
+++ b/drivers/md/dm-cache-target.c
@@ -2061,7 +2061,6 @@
static void writeback_some_dirty_blocks(struct cache *cache)
{
- int r = 0;
dm_oblock_t oblock;
dm_cblock_t cblock;
struct prealloc structs;
@@ -2071,15 +2070,11 @@
memset(&structs, 0, sizeof(structs));
while (spare_migration_bandwidth(cache)) {
- if (prealloc_data_structs(cache, &structs))
- break;
+ if (policy_writeback_work(cache->policy, &oblock, &cblock, busy))
+ break; /* no work to do */
- r = policy_writeback_work(cache->policy, &oblock, &cblock, busy);
- if (r)
- break;
-
- r = get_cell(cache, oblock, &structs, &old_ocell);
- if (r) {
+ if (prealloc_data_structs(cache, &structs) ||
+ get_cell(cache, oblock, &structs, &old_ocell)) {
policy_set_dirty(cache->policy, oblock);
break;
}