Similar to commit 2a8513091d2f ("nvme-rdma: parallelize I/O queue
allocation and startup"), I/O queue allocation and start steps
(including authentication) can be parallelized for nvme-tcp as well.

Patch 1 fixes a pre-existing bug: nvme_tcp_alloc_queue() used
current->nsproxy->net_ns to create sockets during initial connect
while it used kernel's init_net for reconnect and error recovery
paths. The fix captures the caller's network namespace at controller
allocation time.

Patch 2 is a preparatory refactor: it splits the queue-count
negotiation and TLS PSK checks into helpers so that the individual
steps can be called directly from nvme_tcp_configure_io_queues(). No
functional change.

Patch 3 has the async implementation: it fans the per-queue alloc and
start out over an async domain, serializes the per-cpu queue-count in
nvme_tcp_set_queue_io_cpu() that can now run concurrently, and uses
ctrl->net for all socket creation.

Testing on a 64-core host with 64 IO-queues shows nvme-tcp connection
time reduced from 61ms to 11ms.

blktests - nvme suite, TCP transport (nvme_trtype=tcp)

Tested with:
- Ubuntu 22.04 LTS (Jammy Jellyfish), x86_64, KubeVirt VM
- nvme-cli v2.13 / libnvme v1.14 (built with libkeyutils)
- ktls-utils tag ktls-utils-1.4.0 (c63c04b) (tlshd) linked
against gnutls 3.8.5

---
v4:
  - Moved conditional from nvme_tcp_configure_io_queues() to
    nvme_tcp_setup_io_queues().

v3:
  - Added patch 1 fixing a network namespace bug: reconnect and error
    recovery paths were creating sockets in init_net instead of the
    controller's namespace. Patch 3 now uses ctrl->net (from patch 1)
    instead of hardcoding init_net.
  - Patches renumbered accordingly (v2 patch 1->2, patch 2->3).

v2:
  - Resending the entire series to fix missing numbering in the
    original patch 2 subject line. No functional code changes.

v1: https://lore.kernel.org/20260824222939.301887-1-sgogte@purestorage.com/
v2: https://lore.kernel.org/20260824225648.316962-1-sgogte@purestorage.com/
v3: https://lore.kernel.org/20260910202812.1642832-1-sgogte@purestorage.com/
---

Surabhi Gogte (3):
  nvme-tcp: store and use the caller's network namespace
  nvme-tcp: refactor I/O queue setup path
  nvme-tcp: parallelize I/O queue allocation and startup

 drivers/nvme/host/tcp.c | 139 +++++++++++++++++++++++++++-------------
 1 file changed, 96 insertions(+), 43 deletions(-)

-- 
2.55.0