linux-kernel - Re: [PATCH 5/8] module: Add module_for_each

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Message-ID: <20250210140803.yAy54W0Q@linutronix.de>
Date: Mon, 10 Feb 2025 15:08:03 +0100
From: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
To: Petr Pavlu <petr.pavlu@...e.com>
Cc: Steven Rostedt <rostedt@...dmis.org>,
	"Masami Hiramatsu (Google)" <mhiramat@...nel.org>,
	linux-kernel@...r.kernel.org, linux-trace-kernel@...r.kernel.org,
	Mark Rutland <mark.rutland@....com>,
	Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Luis Chamberlain <mcgrof@...nel.org>,
	Sami Tolvanen <samitolvanen@...gle.com>,
	Daniel Gomez <da.gomez@...sung.com>, linux-modules@...r.kernel.org
Subject: Re: [PATCH 5/8] module: Add module_for_each_mod() function

On 2025-02-10 14:04:35 [+0100], Petr Pavlu wrote:
> >> BTW, do we really need to disable preempt or is it enough to call
> >> rcu_read_lock()?
> > 
> > Bah, as I expected this function to be changed, I didn't spend too much
> > time on looking at its implementation. I just cut and pasted how the other
> > loops worked. But yes, it should not be disabling preemption. In fact, I
> > think the module code itself should not be disabling preemption!
> > 
> > I'll have to go and look into that.
> 
> The series "module: Use RCU instead of RCU-sched" from Sebastian Andrzej
> Siewior cleans this up [1]. It is currently queued on modules-next (for
> 6.15-rc1).
> 
> The new function module_for_each_mod() should then use "guard(rcu)();".

So the removal of the preempt-disable statements here already pays off.
Nice.

Sebastian