Re: [PATCH 4/5] i3c: master: Negative error codes at send_ccc_cmd

[Adrian Hunter]

On 08/03/2026 18:47, Jorge Marques wrote:
> i3c_master_send_ccc_cmd_locked would propagate cmd->err (positive,
> Mx codes) to the ret variable, cascading down multiple methods until
> reaching methods that explicitly stated they would return 0 on success
> or negative error code. For example, the call chain:
> 
>   i3c_device_enable_ibi <- i3c_dev_enable_ibi_locked <-
>   master->ops.enable_ibi <- i3c_master_enec_locked <-
>   i3c_master_enec_disec_locked <- i3c_master_send_ccc_cmd_locked
> 
> Fix this by returning the ret value, callers can
> still read the cmd->err value if ret is negative.

You should say something about how you know that is safe
to do. e.g. although there are myriad call paths, the code
never distinguishes positive from negative error codes except
in cases where it explicitly checks for I3C_ERROR_M2 and
those have been dealt with in the preparation patches.

> 
> Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> Closes: https://lore.kernel.org/linux-iio/aYXvT5FW0hXQwhm_@stanley.mountain/

Fixes tag?

> 
> Signed-off-by: Jorge Marques <jorge.marques@xxxxxxxxxx>
> ---
>  drivers/i3c/master.c | 29 ++++++++++++-----------------
>  1 file changed, 12 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
> index 3e465587c9c7..8459fffbdebb 100644
> --- a/drivers/i3c/master.c
> +++ b/drivers/i3c/master.c
> @@ -898,11 +898,17 @@ static void i3c_ccc_cmd_init(struct i3c_ccc_cmd *cmd, bool rnw, u8 id,
>  	cmd->err = I3C_ERROR_UNKNOWN;
>  }
>  
> +/**
> + * i3c_master_send_ccc_cmd_locked() - send a CCC (Common Command Codes)
> + * @master: master used to send frames on the bus
> + * @cmd: command to send
> + *
> + * Return: 0 in case of success, or a negative error code otherwise.
> + *         I3C Mx error codes are stored in cmd->err.
> + */
>  static int i3c_master_send_ccc_cmd_locked(struct i3c_master_controller *master,
>  					  struct i3c_ccc_cmd *cmd)
>  {
> -	int ret;
> -
>  	if (!cmd || !master)
>  		return -EINVAL;
>  
> @@ -920,15 +926,7 @@ static int i3c_master_send_ccc_cmd_locked(struct i3c_master_controller *master,
>  	    !master->ops->supports_ccc_cmd(master, cmd))
>  		return -EOPNOTSUPP;
>  
> -	ret = master->ops->send_ccc_cmd(master, cmd);
> -	if (ret) {
> -		if (cmd->err != I3C_ERROR_UNKNOWN)
> -			return cmd->err;
> -
> -		return ret;
> -	}
> -
> -	return 0;
> +	return master->ops->send_ccc_cmd(master, cmd);
>  }
>  
>  static struct i2c_dev_desc *
> @@ -1101,8 +1099,7 @@ static int i3c_master_enec_disec_locked(struct i3c_master_controller *master,
>   *
>   * This function must be called with the bus lock held in write mode.
>   *
> - * Return: 0 in case of success, a positive I3C error code if the error is
> - * one of the official Mx error codes, and a negative error code otherwise.
> + * Return: 0 in case of success, or a negative error code otherwise.
>   */
>  int i3c_master_disec_locked(struct i3c_master_controller *master, u8 addr,
>  			    u8 evts)
> @@ -1122,8 +1119,7 @@ EXPORT_SYMBOL_GPL(i3c_master_disec_locked);
>   *
>   * This function must be called with the bus lock held in write mode.
>   *
> - * Return: 0 in case of success, a positive I3C error code if the error is
> - * one of the official Mx error codes, and a negative error code otherwise.
> + * Return: 0 in case of success, or a negative error code otherwise.
>   */
>  int i3c_master_enec_locked(struct i3c_master_controller *master, u8 addr,
>  			   u8 evts)
> @@ -1148,8 +1144,7 @@ EXPORT_SYMBOL_GPL(i3c_master_enec_locked);
>   *
>   * This function must be called with the bus lock held in write mode.
>   *
> - * Return: 0 in case of success, a positive I3C error code if the error is
> - * one of the official Mx error codes, and a negative error code otherwise.
> + * Return: 0 in case of success, or a negative error code otherwise.
>   */
>  int i3c_master_defslvs_locked(struct i3c_master_controller *master)
>  {
>