Looks good

Acked-by: Jon Derrick <jonathan.derrick@intel.com>

On Thu, 2019-02-14 at 01:15 +0100, David Kozub wrote:
> From: Jonas Rabenstein <jonas.rabenstein@studium.uni-erlangen.de>
> 
> All add_token_* functions have a common set of conditions that have
> to
> be checked. Use a common function for those checks in order to avoid
> different behaviour as well as code duplication.
> 
> Co-authored-by: David Kozub <zub@linux.fjfi.cvut.cz>
> Signed-off-by: Jonas Rabenstein <
> jonas.rabenstein@studium.uni-erlangen.de>
> Signed-off-by: David Kozub <zub@linux.fjfi.cvut.cz>
> ---
>  block/sed-opal.c | 25 ++++++++++++++++---------
>  1 file changed, 16 insertions(+), 9 deletions(-)
> 
> diff --git a/block/sed-opal.c b/block/sed-opal.c
> index e59ae364f1ef..d285bd4b2b9b 100644
> --- a/block/sed-opal.c
> +++ b/block/sed-opal.c
> @@ -510,15 +510,24 @@ static int opal_discovery0(struct opal_dev
> *dev, void *data)
>  	return opal_discovery0_end(dev);
>  }
>  
> -static void add_token_u8(int *err, struct opal_dev *cmd, u8 tok)
> +static bool can_add(int *err, struct opal_dev *cmd, size_t len)
>  {
>  	if (*err)
> -		return;
> -	if (cmd->pos >= IO_BUFFER_LENGTH - 1) {
> -		pr_debug("Error adding u8: end of buffer.\n");
> +		return false;
> +
> +	if (len > IO_BUFFER_LENGTH || cmd->pos > IO_BUFFER_LENGTH -
> len) {
> +		pr_debug("Error adding %zu bytes: end of buffer.\n",
> len);
>  		*err = -ERANGE;
> -		return;
> +		return false;
>  	}
> +
> +	return true;
> +}
> +
> +static void add_token_u8(int *err, struct opal_dev *cmd, u8 tok)
> +{
> +	if (!can_add(err, cmd, 1))
> +		return;
>  	cmd->cmd[cmd->pos++] = tok;
>  }
>  
> @@ -562,9 +571,8 @@ static void add_token_u64(int *err, struct
> opal_dev *cmd, u64 number)
>  	msb = fls64(number);
>  	len = DIV_ROUND_UP(msb, 8);
>  
> -	if (cmd->pos >= IO_BUFFER_LENGTH - len - 1) {
> +	if (!can_add(err, cmd, len + 1)) {
>  		pr_debug("Error adding u64: end of buffer.\n");
> -		*err = -ERANGE;
>  		return;
>  	}
>  	add_short_atom_header(cmd, false, false, len);
> @@ -586,9 +594,8 @@ static void add_token_bytestring(int *err, struct
> opal_dev *cmd,
>  		is_short_atom = false;
>  	}
>  
> -	if (len >= IO_BUFFER_LENGTH - cmd->pos - header_len) {
> +	if (!can_add(err, cmd, header_len + len)) {
>  		pr_debug("Error adding bytestring: end of buffer.\n");
> -		*err = -ERANGE;
>  		return;
>  	}
>