Re: [PATCH 2/4] binder: migrate ioctl to new PF_SPAM_DETECTION

[Alice Ryhl <aliceryhl@google.com>]

Carlos Llamas <cmllamas@google.com> writes:
> @@ -5553,7 +5553,8 @@ static long binder_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
>  			goto err;
>  		}
>  		binder_inner_proc_lock(proc);
> -		proc->oneway_spam_detection_enabled = (bool)enable;
> +		proc->flags &= ~PF_SPAM_DETECTION;
> +		proc->flags |= enable & PF_SPAM_DETECTION;

The bitwise and in `enable & PF_SPAM_DETECTION` only works because
PF_SPAM_DETECTION happens to be equal to 1. This seems pretty fragile to
me. Would you be willing to do this instead?

proc->flags &= ~PF_SPAM_DETECTION;
if (enable)
	proc->flags |= PF_SPAM_DETECTION;


Carlos Llamas <cmllamas@google.com> writes:
> -			if (proc->oneway_spam_detection_enabled &&
> -				   w->type == BINDER_WORK_TRANSACTION_ONEWAY_SPAM_SUSPECT)
> +			if (proc->flags & PF_SPAM_DETECTION &&
> +			    w->type == BINDER_WORK_TRANSACTION_ONEWAY_SPAM_SUSPECT)

Maybe I am just not sufficiently familiar with C, but I had to look up
the operator precedence rules for this one. Could we add parenthesises
around `proc->flags & PF_SPAM_DETECTION`? Or even define a macro for it?

Alice