Messages in this thread Patch in this message | | | Date | Sat, 20 Apr 2024 23:49:04 +0000 | From | Carlos Llamas <> | Subject | Re: [PATCH 2/4] binder: migrate ioctl to new PF_SPAM_DETECTION |
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On Thu, Apr 18, 2024 at 08:12:22AM +0000, Alice Ryhl wrote: > 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; >
I don't think it is fragile since PF_SPAM_DETECTION is fixed. However, I agree the code is missing context about the flag being bit 0 and your version addresses this problem. So I'll take it for v2, thanks!
> > 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?
I think this is fairly common in C but I can definitly add the extra paranthesis if it helps.
-- Carlos Llamas
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