[PATCH v4 0/2] ublk: introduce UBLK_CMD_TRY_STOP_DEV

[Yoav Cohen <yoav@nvidia.com>]

Hello,

This patch series introduces a new command for ublk device management.

The first patch changes `ublk_ctrl_stop_dev()` to return void, since it
always returned 0. This simplifies the API.

The second patch introduces `UBLK_CMD_TRY_STOP_DEV`, which stops the
device only if there are no active openers. Unlike the existing stop
command (`UBLK_CMD_STOP_DEV`), this command avoids disrupting active
users by returning -EBUSY if the device is busy.

These patches only introduce the new command and API simplification
without altering existing behavior for active users

Changes since v2:
 - Address Ming Lei’s comments in patch 2:
   - Add a feature flag and some minor comments.
 - Patch 1 unchanged, keeps Reviewed-by

Changes since v3:
 - Address Caleb's comments in patch 2
   - add to kublk.c
   - add to auto features
   - set feature flag to 17

Yoav Cohen (2):
  ublk: make ublk_ctrl_stop_dev return void
  ublk: add UBLK_CMD_TRY_STOP_DEV command

 drivers/block/ublk_drv.c             | 50 +++++++++++++++++++++++++---
 include/uapi/linux/ublk_cmd.h        |  9 ++++-
 tools/testing/selftests/ublk/kublk.c |  1 +
 3 files changed, 54 insertions(+), 6 deletions(-)

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2.39.5 (Apple Git-154)