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Maxim Mikityanskiy
8bf30be750
ndo_select_queue can be called at any time, and there is no way to stop the kernel from calling it to synchronize with configuration changes (real_num_tx_queues, num_tc). This commit introduces an internal way in mlx5e to sync mlx5e_select_queue() with these changes. The configuration needed by this function is stored in a struct mlx5e_selq_params, which is modified and accessed in an atomic way using RCU methods. The whole ndo_select_queue is called under an RCU lock, providing the necessary guarantees. The parameters stored in the new struct mlx5e_selq_params should only be used from inside mlx5e_select_queue. It's the minimal set of parameters needed for mlx5e_select_queue to do its job efficiently, derived from parameters stored elsewhere. That means that when the configuration change, mlx5e_selq_params may need to be updated. In such cases, the mlx5e_selq_prepare/mlx5e_selq_apply API should be used. struct mlx5e_selq contains two slots for the params: active and standby. mlx5e_selq_prepare updates the standby slot, and mlx5e_selq_apply swaps the slots in a safe atomic way using the RCU API. It integrates well with the open/activate stages of the configuration change flow. Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com> Reviewed-by: Tariq Toukan <tariqt@nvidia.com> Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.