Re: [PATCH] applicom: Prevent unsigned wrap in ac_interrupt()

[roel kluin]

>> unsigned i wraps if this occurs in the first iteration.
>
> Could you elaborate? I don't quite understand the point.

`i' is unsigned. The last test in the loop is:

if(readb(apbs[i].RamIO + RAM_IT_TO_PC)) {
        /* There's another int waiting on this card */
        spin_unlock(&apbs[i].mutex);
        i--;
} else {
        spin_unlock(&apbs[i].mutex);
}

In the first iteration `i' is 0, so if this condition evaluates to true
then `i' becomes 0xffffffff (since it's unsigned), the for loop test
fails and the i++ never occurs.

>> Or do we know this can't happen?
>
> You mean the i--? It's followed by i++ in the for loop 3rd expression. Or?

No, I meant: do we know the test can't evaluate to true in the first iteration?

Thanks,

Roel
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