On Thu, Jan 24, 2019 at 11:24:37AM +0530, Sumit Garg wrote:
> This flag indicates that requests in this context should not wait for
> tee-supplicant daemon to be started if not present and just return
> with an error code. It is needed for requests which should be
> non-blocking in nature like ones arising from TEE based kernel drivers
> or any in kernel api that uses TEE internal client interface.
> 
> Signed-off-by: Sumit Garg <sumit.g...@linaro.org>

Reviewed-by: Daniel Thompson <daniel.thomp...@linaro.org>

> ---
>  drivers/tee/optee/supp.c | 10 +++++++++-
>  drivers/tee/tee_core.c   | 13 +++++++++++++
>  include/linux/tee_drv.h  |  6 ++++++
>  3 files changed, 28 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/tee/optee/supp.c b/drivers/tee/optee/supp.c
> index 43626e1..92f56b8 100644
> --- a/drivers/tee/optee/supp.c
> +++ b/drivers/tee/optee/supp.c
> @@ -88,10 +88,18 @@ u32 optee_supp_thrd_req(struct tee_context *ctx, u32 
> func, size_t num_params,
>  {
>       struct optee *optee = tee_get_drvdata(ctx->teedev);
>       struct optee_supp *supp = &optee->supp;
> -     struct optee_supp_req *req = kzalloc(sizeof(*req), GFP_KERNEL);
> +     struct optee_supp_req *req;
>       bool interruptable;
>       u32 ret;
>  
> +     /*
> +      * Return in case there is no supplicant available and
> +      * non-blocking request.
> +      */
> +     if (!supp->ctx && ctx->supp_nowait)
> +             return TEEC_ERROR_COMMUNICATION;
> +
> +     req = kzalloc(sizeof(*req), GFP_KERNEL);
>       if (!req)
>               return TEEC_ERROR_OUT_OF_MEMORY;
>  
> diff --git a/drivers/tee/tee_core.c b/drivers/tee/tee_core.c
> index 9f4c8bc..2612dfa 100644
> --- a/drivers/tee/tee_core.c
> +++ b/drivers/tee/tee_core.c
> @@ -105,6 +105,11 @@ static int tee_open(struct inode *inode, struct file 
> *filp)
>       if (IS_ERR(ctx))
>               return PTR_ERR(ctx);
>  
> +     /*
> +      * Default user-space behaviour is to wait for tee-supplicant
> +      * if not present for any requests in this context.
> +      */
> +     ctx->supp_nowait = false;
>       filp->private_data = ctx;
>       return 0;
>  }
> @@ -981,6 +986,14 @@ tee_client_open_context(struct tee_context *start,
>       } while (IS_ERR(ctx) && PTR_ERR(ctx) != -ENOMEM);
>  
>       put_device(put_dev);
> +     /*
> +      * Default behaviour for in kernel client is to not wait for
> +      * tee-supplicant if not present for any requests in this context.
> +      * Also this flag could be configured again before call to
> +      * tee_client_open_session() if any in kernel client requires
> +      * different behaviour.
> +      */
> +     ctx->supp_nowait = true;
>       return ctx;
>  }
>  EXPORT_SYMBOL_GPL(tee_client_open_context);
> diff --git a/include/linux/tee_drv.h b/include/linux/tee_drv.h
> index ce957ce..56d7f1b 100644
> --- a/include/linux/tee_drv.h
> +++ b/include/linux/tee_drv.h
> @@ -50,6 +50,11 @@ struct tee_shm_pool;
>   * @releasing:  flag that indicates if context is being released right now.
>   *           It is needed to break circular dependency on context during
>   *              shared memory release.
> + * @supp_nowait: flag that indicates that requests in this context should not
> + *              wait for tee-supplicant daemon to be started if not present
> + *              and just return with an error code. It is needed for requests
> + *              that arises from TEE based kernel drivers that should be
> + *              non-blocking in nature.
>   */
>  struct tee_context {
>       struct tee_device *teedev;
> @@ -57,6 +62,7 @@ struct tee_context {
>       void *data;
>       struct kref refcount;
>       bool releasing;
> +     bool supp_nowait;
>  };
>  
>  struct tee_param_memref {
> -- 
> 2.7.4
> 

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