On Fri, Aug 16, 2024 at 11:02 AM Dragos Tatulea <dtatulea@xxxxxxxxxx> wrote:
>
> Introduce a new function mlx5_vdpa_exec_async_cmds() which
> wraps the mlx5_core async firmware command API in a way
> that will be used to parallelize certain operation in this
> driver.
>
> The wrapper deals with the case when mlx5_cmd_exec_cb() returns
> EBUSY due to the command being throttled.
>
> Signed-off-by: Dragos Tatulea <dtatulea@xxxxxxxxxx>
> Reviewed-by: Tariq Toukan <tariqt@xxxxxxxxxx>
Acked-by: Eugenio Pérez <eperezma@xxxxxxxxxx>
> ---
> drivers/vdpa/mlx5/core/mlx5_vdpa.h | 15 ++++++
> drivers/vdpa/mlx5/core/resources.c | 73 ++++++++++++++++++++++++++++++
> 2 files changed, 88 insertions(+)
>
> diff --git a/drivers/vdpa/mlx5/core/mlx5_vdpa.h b/drivers/vdpa/mlx5/core/mlx5_vdpa.h
> index 424d445ebee4..b34e9b93d56e 100644
> --- a/drivers/vdpa/mlx5/core/mlx5_vdpa.h
> +++ b/drivers/vdpa/mlx5/core/mlx5_vdpa.h
> @@ -105,6 +105,18 @@ struct mlx5_vdpa_dev {
> bool suspended;
> };
>
> +struct mlx5_vdpa_async_cmd {
> + int err;
> + struct mlx5_async_work cb_work;
> + struct completion cmd_done;
> +
> + void *in;
> + size_t inlen;
> +
> + void *out;
> + size_t outlen;
> +};
> +
> int mlx5_vdpa_create_tis(struct mlx5_vdpa_dev *mvdev, void *in, u32 *tisn);
> void mlx5_vdpa_destroy_tis(struct mlx5_vdpa_dev *mvdev, u32 tisn);
> int mlx5_vdpa_create_rqt(struct mlx5_vdpa_dev *mvdev, void *in, int inlen, u32 *rqtn);
> @@ -134,6 +146,9 @@ int mlx5_vdpa_update_cvq_iotlb(struct mlx5_vdpa_dev *mvdev,
> unsigned int asid);
> int mlx5_vdpa_create_dma_mr(struct mlx5_vdpa_dev *mvdev);
> int mlx5_vdpa_reset_mr(struct mlx5_vdpa_dev *mvdev, unsigned int asid);
> +int mlx5_vdpa_exec_async_cmds(struct mlx5_vdpa_dev *mvdev,
> + struct mlx5_vdpa_async_cmd *cmds,
> + int num_cmds);
>
> #define mlx5_vdpa_err(__dev, format, ...) \
> dev_err((__dev)->mdev->device, "%s:%d:(pid %d) error: " format, __func__, __LINE__, \
> diff --git a/drivers/vdpa/mlx5/core/resources.c b/drivers/vdpa/mlx5/core/resources.c
> index 5c5a41b64bfc..22ea32fe007b 100644
> --- a/drivers/vdpa/mlx5/core/resources.c
> +++ b/drivers/vdpa/mlx5/core/resources.c
> @@ -321,3 +321,76 @@ void mlx5_vdpa_free_resources(struct mlx5_vdpa_dev *mvdev)
> mutex_destroy(&mvdev->mr_mtx);
> res->valid = false;
> }
> +
> +static void virtqueue_cmd_callback(int status, struct mlx5_async_work *context)
> +{
> + struct mlx5_vdpa_async_cmd *cmd =
> + container_of(context, struct mlx5_vdpa_async_cmd, cb_work);
> +
> + cmd->err = mlx5_cmd_check(context->ctx->dev, status, cmd->in, cmd->out);
> + complete(&cmd->cmd_done);
> +}
> +
> +static int issue_async_cmd(struct mlx5_vdpa_dev *mvdev,
> + struct mlx5_vdpa_async_cmd *cmds,
> + int issued,
> + int *completed)
> +
> +{
> + struct mlx5_vdpa_async_cmd *cmd = &cmds[issued];
> + int err;
> +
> +retry:
> + err = mlx5_cmd_exec_cb(&mvdev->async_ctx,
> + cmd->in, cmd->inlen,
> + cmd->out, cmd->outlen,
> + virtqueue_cmd_callback,
> + &cmd->cb_work);
> + if (err == -EBUSY) {
> + if (*completed < issued) {
> + /* Throttled by own commands: wait for oldest completion. */
> + wait_for_completion(&cmds[*completed].cmd_done);
> + (*completed)++;
> +
> + goto retry;
> + } else {
> + /* Throttled by external commands: switch to sync api. */
> + err = mlx5_cmd_exec(mvdev->mdev,
> + cmd->in, cmd->inlen,
> + cmd->out, cmd->outlen);
> + if (!err)
> + (*completed)++;
> + }
> + }
> +
> + return err;
> +}
> +
> +int mlx5_vdpa_exec_async_cmds(struct mlx5_vdpa_dev *mvdev,
> + struct mlx5_vdpa_async_cmd *cmds,
> + int num_cmds)
> +{
> + int completed = 0;
> + int issued = 0;
> + int err = 0;
> +
> + for (int i = 0; i < num_cmds; i++)
> + init_completion(&cmds[i].cmd_done);
> +
> + while (issued < num_cmds) {
> +
> + err = issue_async_cmd(mvdev, cmds, issued, &completed);
> + if (err) {
> + mlx5_vdpa_err(mvdev, "error issuing command %d of %d: %d\n",
> + issued, num_cmds, err);
> + break;
> + }
> +
> + issued++;
> + }
> +
> + while (completed < issued)
> + wait_for_completion(&cmds[completed++].cmd_done);
> +
> + return err;
> +}
> --
> 2.45.1
>
