Re: [PATCH v4 01/16] firmware: arm_scmi: Fix max pending messages boundary check

[Peter Hilber]

Hi Cristian,

please find some remarks to the patch series in this email and the 
following.

On 11.06.21 18:59, Cristian Marussi wrote:
> SCMI message headers carry a sequence number and such field is sized to
> allow for MSG_TOKEN_MAX distinct numbers; moreover zero is not really an
> acceptable maximum number of pending in-flight messages.
>
> Fix accordignly the checks performed on the value exported by transports
> in scmi_desc.max_msg.
>
> Reported-by: Vincent Guittot <vincent.guittot@xxxxxxxxxx>
> Fixes: aa4f886f3893 ("firmware: arm_scmi: add basic driver infrastructure for SCMI")
> Signed-off-by: Cristian Marussi <cristian.marussi@xxxxxxx>
> ---
>  drivers/firmware/arm_scmi/driver.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c
> index 66e5e694be7d..6713b259f1e6 100644
> --- a/drivers/firmware/arm_scmi/driver.c
> +++ b/drivers/firmware/arm_scmi/driver.c
> @@ -1025,8 +1025,9 @@ static int __scmi_xfer_info_init(struct scmi_info *sinfo,
>  	const struct scmi_desc *desc = sinfo->desc;
>  
>  	/* Pre-allocated messages, no more than what hdr.seq can support */
> -	if (WARN_ON(desc->max_msg >= MSG_TOKEN_MAX)) {
> -		dev_err(dev, "Maximum message of %d exceeds supported %ld\n",
> +	if (WARN_ON(!desc->max_msg || desc->max_msg > MSG_TOKEN_MAX)) {
> +		dev_err(dev,
> +			"Invalid max_msg %d. Maximum messages supported %ld.\n",

%ld -> %lu

>  			desc->max_msg, MSG_TOKEN_MAX);
>  		return -EINVAL;
>  	}