Re: [PRE-REVIEW PATCH 02/16] crypto: ccp - Prepare to use the new tasklet API

[Kees Cook <keescook@chromium.org>]

On Sun, Sep 29, 2019 at 06:30:14PM +0200, Romain Perier wrote:
> Currently, the tasklet and its "tdata" has no relationship. The future
> tasklet API, will no longer allow to pass an arbitrary "unsigned long"
> data parameter. The tasklet data structure will need to be embedded into
> a data structure that will be retrieved from the tasklet handler (most
> of the time, it is the driver data structure). This commit prepares the
> driver to this change. For doing so, it embeds "tasklet" into "tdata".
> Then, "tdata" will be recoverable from its "tasklet" field, with the
> tasklet API.
> 
> Signed-off-by: Romain Perier <romain.perier@gmail.com>
> ---
>  drivers/crypto/ccp/ccp-dev.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/crypto/ccp/ccp-dev.c b/drivers/crypto/ccp/ccp-dev.c
> index 73acf0fdb793..d0d180176f45 100644
> --- a/drivers/crypto/ccp/ccp-dev.c
> +++ b/drivers/crypto/ccp/ccp-dev.c
> @@ -44,6 +44,7 @@ MODULE_PARM_DESC(max_devs, "Maximum number of CCPs to enable (default: all; 0 di
>  struct ccp_tasklet_data {
>  	struct completion completion;
>  	struct ccp_cmd *cmd;
> +	struct tasklet_struct tasklet;
>  };
>  
>  /* Human-readable error strings */
> @@ -436,9 +437,8 @@ int ccp_cmd_queue_thread(void *data)
>  	struct ccp_cmd_queue *cmd_q = (struct ccp_cmd_queue *)data;
>  	struct ccp_cmd *cmd;
>  	struct ccp_tasklet_data tdata;
> -	struct tasklet_struct tasklet;
>  
> -	tasklet_init(&tasklet, ccp_do_cmd_complete, (unsigned long)&tdata);
> +	tasklet_init(&tdata.tasklet, ccp_do_cmd_complete, (unsigned long)&tdata);

Why not switch to tasklet_setup() here to avoid changing this again
later?

-Kees

>  
>  	set_current_state(TASK_INTERRUPTIBLE);
>  	while (!kthread_should_stop()) {
> @@ -458,7 +458,7 @@ int ccp_cmd_queue_thread(void *data)
>  		/* Schedule the completion callback */
>  		tdata.cmd = cmd;
>  		init_completion(&tdata.completion);
> -		tasklet_schedule(&tasklet);
> +		tasklet_schedule(&tdata.tasklet);
>  		wait_for_completion(&tdata.completion);
>  	}
>  
> -- 
> 2.23.0
> 

-- 
Kees Cook