[PATCH v2 00/15] nvmet-fcloop: track resources via reference counting

[Daniel Wagner]

The idea to use ref counting for tport and rport didn't work well. fcloop
was to eager to remove resources when the assocication was torn down.
Thus I looked more closely how the existing solution is supposed to work
and fixed all the problems I found.

This also avoids taking references for a nport and a rport/tport step in
step which Hannes was not happy with.

With all these changes it is possible to add/remove the target side and
nothing blows up anymore. There is just one small issue left with
nvme/030. The problem is that the test case assumes that the generation
counter is updated immediately but for FC it takes a bit, thus the test
fails. A sleep before reading the genctr 'fixes' it:

@@ -36,27 +36,32 @@ test() {
 	_add_nvmet_subsys_to_port "${port}" "${subsys}1"
 	_create_nvmet_host "${subsys}1" "${def_hostnqn}"

+	sleep 1
 	genctr=$(_discovery_genctr "$port")
[...]

There is another problem I was not able to figure out so far. When I run
blktests in a loop, the system runs out of memory eventually.

Signed-off-by: Daniel Wagner <wagi at 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 (15):
      nvmet-fcloop: remove nport from list on last user
      nvmet-fcloop: replace kref with refcount
      nvmet-fcloop: add ref counting to lport
      nvmet-fcloop: refactor fcloop_nport_alloc
      nvmet-fcloop: track ref counts for nports
      nvmet-fcloop: sync targetport removal
      nvmet-fcloop: update refs on tfcp_req
      nvmet-fcloop: add missing fcloop_callback_host_done
      nvmet-fc: update tgtport ref per assoc
      nvmet-fc: take tgtport reference only once
      nvmet-fc: free pending reqs on tgtport unregister
      nvmet-fc: inline nvmet_fc_delete_assoc
      nvmet-fc: inline nvmet_fc_free_hostport
      nvmet-fc: take tgtport refs for portentry
      nvmet-fc: put ref when assoc->del_work is already scheduled

 drivers/nvme/target/fc.c     | 146 ++++++++++-------
 drivers/nvme/target/fcloop.c | 366 +++++++++++++++++++++++++------------------
 2 files changed, 308 insertions(+), 204 deletions(-)
---
base-commit: 4bfed375fd3acdfa4324acaf22f7664e4819fbb1
change-id: 20250214-nvmet-fcloop-a649738b7e6e

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