[PATCH v2 0/3] null_blk: zone resource management fixes

[Niklas Cassel <cassel@kernel.org>]

Patch 1 fixes writing, opening and finishing a closed zone when both the
open and the active zone limits are reached: null_blk fails the request
instead of closing an implicitly open zone, as ZBC-3 and NVMe ZNS
require.

Patch 2 fixes zone_readonly and zone_offline, which can close an
unrelated zone, or leak the closed zone count.

Patch 3 cleans up the code that sets zones read-only or offline, with
no functional change.

Both issues were reproduced, and the fixes tested, in QEMU, with
null_blk devices created through configfs (memory_backed=0 and 1,
CONFIG_PROVE_LOCKING=y).

Developed with the help of an AI coding assistant.

Changes since v1:
- Picked up Reviewed-by tags from Damien on patches 1 and 2.
- New patch 3, a cleanup suggested by Damien.

Niklas Cassel (3):
  null_blk: fix opening closed zones at the active zone limit
  null_blk: don't finish zones to set them read-only or offline
  null_blk: clean up setting zones read-only or offline

 drivers/block/null_blk/zoned.c | 63 +++++++++++++++++++++++++---------
 1 file changed, 46 insertions(+), 17 deletions(-)


base-commit: f47d223627f80cb7a1eb14c585fe6cb35de5e984
-- 
2.56.0