net: mana: Create separate EQs for each vPort

net: mana: Create separate EQs for each vPort

To prepare for assigning vPorts to dedicated MSI-X vectors, remove EQ
sharing among the vPorts and create dedicated EQs for each vPort.

Move the EQ definition from struct mana_context to struct mana_port_context
and update related support functions. Export mana_create_eq() and
mana_destroy_eq() for use by the MANA RDMA driver.

RSS QPs now take a vport reference via pd->vport_use_count to ensure
EQs outlive all QP consumers. The vport must already be configured by
a raw QP before an RSS QP can be created. EQs are only destroyed when
the last QP (raw or RSS) on the PD releases its reference.

Restrict each vport to a single RSS QP. The hardware only supports one
steering configuration (indirection table / hash key) per vport, and
mana_disable_vport_rx() on QP destroy disables RX globally for the
vport. Previously, creating a second RSS QP would silently overwrite
the first QP's steering config and destroy would blackhole all traffic.
This is now explicitly rejected with -EBUSY. Existing applications
(DPDK being the primary RDMA consumer) always create one RSS QP per
vport, so no real-world flows are affected.

Reject cross-port PD sharing for both raw and RSS QPs. Since EQs and
vport configuration are per-port, a PD is bound to the port used by
its first raw QP. Subsequent QPs on the same PD must use the same
port or the creation fails with -EINVAL. Previously this was silently
broken: with shared EQs it appeared to work, but with per-vPort EQs
a cross-port PD would cause wrong-port EQ teardown and corruption.
DPDK creates one PD per port so no existing flows are affected.

Serialize mana_set_channels() and the async per-port queue reset
handler against RDMA vport configuration to prevent RDMA from claiming
the vport during the detach/attach window. A channel_changing flag is
set under apc->vport_mutex before detach and checked by
mana_cfg_vport() when called from the RDMA path, blocking RDMA from
grabbing the vport during the entire window. When the port is down
and RDMA already holds the vport, the channel change is rejected with
-EBUSY.

Signed-off-by: Long Li <longli@microsoft.com>
Link: https://patch.msgid.link/20260605005717.2059954-2-longli@microsoft.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>