net/mlx5e: kTLS, Recycle objects of device-offloaded TLS TX connections

net/mlx5e: kTLS, Recycle objects of device-offloaded TLS TX connections

The transport interface send (TIS) object is responsible for performing
all transport related operations of the transmit side.  The ConnectX HW
uses a TIS object to save and access the TLS crypto information and state
of an offloaded TX kTLS connection.

Before this patch, we used to create a new TIS per connection and destroy
it once it’s closed. Every create and destroy of a TIS is a FW command.

Same applies for the private TLS context, where we used to dynamically
allocate and free it per connection.

Resources recycling reduce the impact of the allocation/free operations
and helps speeding up the connection rate.

In this feature we maintain a pool of TX objects and use it to recycle
the resources instead of re-creating them per connection.

A cached TIS popped from the pool is updated to serve the new connection
via the fast-path HW interface, updating the tls static and progress
params. This is a very fast operation, significantly faster than FW
commands.

On recycling, a WQE fence is required after the context params change.
This guarantees that the data is sent after the context has been
successfully updated in hardware, and that the context modification
doesn't interfere with existing traffic.

Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Reviewed-by: Gal Pressman <gal@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>