[PATCH v5 00/14] nvmet-fcloop: track resources via reference counting

[Daniel Wagner <wagi@kernel.org>]

This is just a rebase to nvme/nvme-6.15 which ships the first part of the
original series. The rest is still the same, thus:

The main changes are the reordering (so that the tests pass for each
patch) and holding the lock in fcloop_nport_alloc. Also I've
splitted the different changes so that it is simpler to follow, e.g.
'nvmet-fcloop: refactor fcloop_delete_local_port'

Note blktests nvme/030 test is likely to fail if the
70-nvmf-autoconnect.rules is active. In this case two discovery are
running in parallel and nvme-cli/libnvme gets out of sync. I don't see a
problem in blktests, but maybe I am just blind:

nvme/030 (tr=fc) (ensure the discovery generation counter is updated appropriately) [failed]
    runtime  1.843s  ...  1.719s
    --- tests/nvme/030.out      2023-08-30 08:39:08.428409596 +0000
    +++ /tmp/blktests/nodev_tr_fc/nvme/030.out.bad      2025-04-10 10:56:05.146372112 +0000
    @@ -1,2 +1,6 @@
     Running nvme/030
    +Failed to open ctrl nvme1, errno 11
    +Failed to open ctrl nvme1, errno 11
    +failed to get discovery log: Bad file descriptor

The host, target and fcloop work just fine:

[ 1434.556136] run blktests nvme/030 at 2025-04-10 10:56:03
[ 1434.779180] nvmet: adding nsid 1 to subsystem blktests-subsystem-1
[ 1434.858814] nvme nvme1: NVME-FC{0}: create association : host wwpn 0x20001100aa000001  rport wwpn 0x20001100ab000001: NQN "nqn.2014-08.org.nvmexpress.discovery"
[ 1434.860275] (NULL device *): {0:0} Association created
[ 1434.861773] nvmet: Created discovery controller 1 for subsystem nqn.2014-08.org.nvmexpress.discovery for NQN nqn.2014-08.org.nvmexpress:uuid:a94a718e-09b2-4b5b-898a-116845846761.
[ 1434.864704] nvme nvme1: NVME-FC{0}: controller connect complete
[ 1434.865082] nvme nvme1: NVME-FC{0}: new ctrl: NQN "nqn.2014-08.org.nvmexpress.discovery", hostnqn: nqn.2014-08.org.nvmexpress:uuid:a94a718e-09b2-4b5b-898a-116845846761
[ 1434.871357] nvme nvme1: Removing ctrl: NQN "nqn.2014-08.org.nvmexpress.discovery"
[ 1434.953940] nvmet: adding nsid 1 to subsystem blktests-subsystem-2
[ 1434.954581] (NULL device *): {0:0} Association deleted
[ 1435.007936] (NULL device *): {0:0} Association freed
[ 1435.009560] (NULL device *): Disconnect LS failed: No Association
[ 1435.060507] nvme nvme2: NVME-FC{1}: create association : host wwpn 0x20001100aa000001  rport wwpn 0x20001100ab000001: NQN "nqn.2014-08.org.nvmexpress.discovery"
[ 1435.061682] (NULL device *): {0:0} Association created
[ 1435.062499] nvmet: Created discovery controller 1 for subsystem nqn.2014-08.org.nvmexpress.discovery for NQN nqn.2014-08.org.nvmexpress:uuid:0f01fb42-9f7f-4856-b0b3-51e60b8de349.
[ 1435.064831] nvme nvme2: NVME-FC{1}: controller connect complete
[ 1435.065244] nvme nvme2: NVME-FC{1}: new ctrl: NQN "nqn.2014-08.org.nvmexpress.discovery", hostnqn: nqn.2014-08.org.nvmexpress:uuid:0f01fb42-9f7f-4856-b0b3-51e60b8de349
[ 1435.070407] nvme nvme2: Removing ctrl: NQN "nqn.2014-08.org.nvmexpress.discovery"
[ 1435.143134] (NULL device *): {0:0} Association deleted
[ 1435.181772] (NULL device *): {0:0} Association freed
[ 1435.182360] (NULL device *): Disconnect LS failed: No Association

When disabling the udev rule this test will pass. Tracking this
at https://github.com/linux-nvme/nvme-cli/issues/2781

Signed-off-by: Daniel Wagner <wagi@kernel.org>
---
Changes in v5:
- rebased to nvme/nvme-6.15
- Link to v4: https://patch.msgid.link/20250410-nvmet-fcloop-v4-0-7e5c42b7b2cb@kernel.org

Changes in v4:
- reordered patches so that they pass the tests each on of its own
- addressed feedback from Christop, Hannes and James.
- hold lock while looking up nport and insert nport operation in fcloop_nport_alloc
- dropped patches from 20250408-nvmet-fcloop-part-one-v1-0-382ec97ab7eb@kernel.org
- Link to v3: https://lore.kernel.org/r/20250318-nvmet-fcloop-v3-0-05fec0fc02f6@kernel.org

Changes in v3:
- fixed memory leaks
- allocates fcloop_lsreq in fcloop directly
- prevent double free due to unregister race
- collected tags
- Link to v2: https://lore.kernel.org/r/20250311-nvmet-fcloop-v2-0-fc40cb64edea@kernel.org

Changes in v2:
- drop tport and rport ref counting, use implicit synchronisation
- a bunch of additional fixes in existing ref countig
- replaced kref with refcount
- Link to v1: https://lore.kernel.org/r/20250226-nvmet-fcloop-v1-0-c0bd83d43e6a@kernel.org

---
Daniel Wagner (14):
      nvmet-fcloop: track ref counts for nports
      nvmet-fcloop: remove nport from list on last user
      nvmet-fcloop: refactor fcloop_nport_alloc and track lport
      nvmet-fcloop: refactor fcloop_delete_local_port
      nvmet-fcloop: update refs on tfcp_req
      nvmet-fcloop: add missing fcloop_callback_host_done
      nvmet-fcloop: access fcpreq only when holding reqlock
      nvmet-fcloop: prevent double port deletion
      nvmet-fcloop: allocate/free fcloop_lsreq directly
      nvmet-fcloop: don't wait for lport cleanup
      nvmet-fcloop: drop response if targetport is gone
      nvmet-fc: free pending reqs on tgtport unregister
      nvmet-fc: take tgtport refs for portentry
      nvme-fc: do not reference lsrsp after failure

 drivers/nvme/host/fc.c       |  13 +-
 drivers/nvme/target/fc.c     |  85 +++++++--
 drivers/nvme/target/fcloop.c | 437 ++++++++++++++++++++++++++++---------------
 3 files changed, 364 insertions(+), 171 deletions(-)
---
base-commit: 3d7aa0c7b4e96cd460826d932e44710cdeb3378b
change-id: 20250214-nvmet-fcloop-a649738b7e6e

Best regards,
-- 
Daniel Wagner <wagi@kernel.org>