dm cache policy: fix description of lookup fn

Correct the documented requirement on the return code from dm cache policy
lookup functions stated in the policy module header file.

Signed-off-by: Alasdair G Kergon <agk@redhat.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/drivers/md/dm-cache-policy.h b/drivers/md/dm-cache-policy.h
index 558bdfdabf5f..33369ca9614f 100644
--- a/drivers/md/dm-cache-policy.h
+++ b/drivers/md/dm-cache-policy.h
@@ -130,8 +130,8 @@ struct dm_cache_policy {
          *
          * Must not block.
          *
-         * Returns 1 iff in cache, 0 iff not, < 0 on error (-EWOULDBLOCK
-         * would be typical).
+         * Returns 0 if in cache, -ENOENT if not, < 0 for other errors
+         * (-EWOULDBLOCK would be typical).
          */
         int (*lookup)(struct dm_cache_policy *p, dm_oblock_t oblock, dm_cblock_t *cblock);