linux-kernel - Re: [PATCH v2 1/2] jump_label: Explicitly disable jump labels in _

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Date:   Sat, 17 Feb 2018 21:13:06 +0100 (CET)
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Josh Poimboeuf <jpoimboe@...hat.com>
cc:     Ingo Molnar <mingo@...nel.org>, x86@...nel.org,
        linux-kernel@...r.kernel.org, Steven Rostedt <rostedt@...dmis.org>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Jason Baron <jbaron@...mai.com>, Borislav Petkov <bp@...e.de>
Subject: Re: [PATCH v2 1/2] jump_label: Explicitly disable jump labels in
 __init code

On Sat, 17 Feb 2018, Josh Poimboeuf wrote:
> On Sat, Feb 17, 2018 at 11:38:48AM +0100, Ingo Molnar wrote:
> > 
> > * Josh Poimboeuf <jpoimboe@...hat.com> wrote:
> > 
> > > +/* Disable any jump label entries in __init code */
> > > +void __init jump_label_invalidate_init(void)
> > > +{
> > > +	struct jump_entry *iter_start = __start___jump_table;
> > > +	struct jump_entry *iter_stop = __stop___jump_table;
> > > +	struct jump_entry *iter;
> > > +
> > > +	for (iter = iter_start; iter < iter_stop; iter++)
> > > +		if (iter->code >= (unsigned long)_sinittext &&
> > > +		    iter->code < (unsigned long)_einittext)
> > > +			iter->code = 0;
> > > +}
> > > +
> > > +/* Disable any jump label entries in module init code */
> > >  static void jump_label_invalidate_module_init(struct module *mod)
> > >  {
> > >  	struct jump_entry *iter_start = mod->jump_entries;
> > >  	struct jump_entry *iter_stop = iter_start + mod->num_jump_entries;
> > >  	struct jump_entry *iter;
> > >  
> > > -	for (iter = iter_start; iter < iter_stop; iter++) {
> > > +	for (iter = iter_start; iter < iter_stop; iter++)
> > >  		if (within_module_init(iter->code, mod))
> > >  			iter->code = 0;
> > > -	}
> > 
> > Why did you remove the curly braces? They are canonical kernel style for 
> > multi-line statements.
> 
> Personally I prefer the more compact version, but I have no problem
> changing it.

Yes, it's certainly a matter of taste. Here is the reason why myself and
others prefer the version with braces:

       https://marc.info/?l=linux-kernel&m=148467980905537&w=2

Thanks,

	tglx