[PATCH] mtd: nand: ecc-hamming: Clarify the logic around rp17

[Dan Carpenter]

On Thu, Oct 29, 2020 at 09:38:47AM +0100, Miquel Raynal wrote:
> This code has been written in 2008 and is fine, but in order to keep
> robots happy, I think it's time to change a little bit this code just
> to clarify the different possible values of eccsize_mult. Indeed, this
> variable may only take the value 1 or 2 because step_size, in the case
> of the software Hamming ECC engine may only be 256 or 512. Depending
> on the value of eccsize_mult, an extra rp17 variable is set, or not
> and triggers the following warning:
> 
>      smatch warnings:
>      ecc_sw_hamming_calculate() error: uninitialized symbol 'rp17'.
> 
> As highlighted by Dan Carpenter, if the only possible values for
> eccsize_mult are 1 and 2, then the code is fine, but "it's hard to
> tell just from looking".
> 
> So instead of shifting step_size, let's use a ternary condition to
> assign to eccsize_mult the only two possible values and clarify the
> driver's logic.
> 
> Now that the situation is clarified for humans, set rp17 to 0 in an
> else block to keep robots silent as well.

Smatch will parse it correctly with just the ternary change but there
might be other checkers which want the the else statement.  I'm not
sure.  GCC doesn't seem to warn about uninitialized variables these
days.

regards,
dan carpenter