[PATCH] ublk: fix misleading FETCH_REQ comment about cqe->user_data

The FETCH_REQ comment claims the request's tag can be "retrieved via
cqe->userdata", which is misleading. The kernel does not set user_data;
it is the server that should encode the tag into user_data.

Signed-off-by: Yitang Yang <[email protected]>
---
 include/uapi/linux/ublk_cmd.h | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/include/uapi/linux/ublk_cmd.h b/include/uapi/linux/ublk_cmd.h
index 6991370a72ce..0db3de7b5194 100644
--- a/include/uapi/linux/ublk_cmd.h
+++ b/include/uapi/linux/ublk_cmd.h
@@ -106,9 +106,10 @@ struct ublk_shmem_buf_reg {
  * IO commands, issued by ublk server, and handled by ublk driver.
  *
  * FETCH_REQ: issued via sqe(URING_CMD) beforehand for fetching IO request
- *      from ublk driver, should be issued only when starting device. After
- *      the associated cqe is returned, request's tag can be retrieved via
- *      cqe->userdata.
+ *      from ublk driver, should be issued only when starting device. The
+ *      server could encode request's tag in sqe->user_data so that after
+ *      the associated cqe is returned, request's tag can be retrieved from
+ *      the same field.
  *
  * COMMIT_AND_FETCH_REQ: issued via sqe(URING_CMD) after ublkserver handled
  *      this IO request, request's handling result is committed to ublk
-- 
2.43.0