ice: fix rebuilding the Tx scheduler tree for large queue counts

The current implementation of the Tx scheduler allows the tree to be
rebuilt as the user adds more Tx queues to the VSI. In such a case,
additional child nodes are added to the tree to support the new number
of queues.
Unfortunately, this algorithm does not take into account that the limit
of the VSI support node may be exceeded, so an additional node in the
VSI layer may be required to handle all the requested queues.

Such a scenario occurs when adding XDP Tx queues on machines with many
CPUs. Although the driver still respects the queue limit returned by
the FW, the Tx scheduler was unable to add those queues to its tree
and returned one of the errors below.

Such a scenario occurs when adding XDP Tx queues on machines with many
CPUs (e.g. at least 321 CPUs, if there is already 128 Tx/Rx queue pairs).
Although the driver still respects the queue limit returned by the FW,
the Tx scheduler was unable to add those queues to its tree and returned
the following errors:

     Failed VSI LAN queue config for XDP, error: -5
or:
     Failed to set LAN Tx queue context, error: -22

Fix this problem by extending the tree rebuild algorithm to check if the
current VSI node can support the requested number of queues. If it
cannot, create as many additional VSI support nodes as necessary to
handle all the required Tx queues. Symmetrically, adjust the VSI node
removal algorithm to remove all nodes associated with the given VSI.
Also, make the search for the next free VSI node more restrictive. That is,
add queue group nodes only to the VSI support nodes that have a matching
VSI handle.
Finally, fix the comment describing the tree update algorithm to better
reflect the current scenario.

Fixes: b0153fdd7e8a ("ice: update VSI config dynamically")
Reviewed-by: Dawid Osuchowski <dawid.osuchowski@linux.intel.com>
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Signed-off-by: Michal Kubiak <michal.kubiak@intel.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Tested-by: Jesse Brandeburg <jbrandeburg@cloudflare.com>
Tested-by: Saritha Sanigani <sarithax.sanigani@intel.com> (A Contingent Worker at Intel)
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

0 files changed, 0 insertions, 0 deletions