Commit 3e127583 authored by Steven Rostedt (Google)'s avatar Steven Rostedt (Google)
Browse files

x86/mm/kmmio: Remove redundant preempt_disable() 

Now that kmmio uses rcu_read_lock_sched_notrace() there's no reason to
call preempt_disable() as the read_lock_sched_notrace() already does that
and is redundant.

This also removes the preempt_enable_no_resched() as the "no_resched()"
portion was bogus as there's no reason to do that.

Link: https://lkml.kernel.org/r/20221212103703.7129cc5d@gandalf.local.home



Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "x86@kernel.org" <x86@kernel.org>
Cc: Karol Herbst <karolherbst@gmail.com>
Cc: Pekka Paalanen <ppaalanen@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
parent c1ac03af

arch/x86/mm/kmmio.c

+5 −8
Original line number Diff line number Diff line
@@ -246,14 +246,13 @@ int kmmio_handler(struct pt_regs *regs, unsigned long addr) 
	page_base &= page_level_mask(l);



	/*

	 * Preemption is now disabled to prevent process switch during

	 * single stepping. We can only handle one active kmmio trace

	 * Hold the RCU read lock over single stepping to avoid looking

	 * up the probe and kmmio_fault_page again. The rcu_read_lock_sched()

	 * also disables preemption and prevents process switch during

	 * the single stepping. We can only handle one active kmmio trace

	 * per cpu, so ensure that we finish it before something else

	 * gets to run. We also hold the RCU read lock over single

	 * stepping to avoid looking up the probe and kmmio_fault_page

	 * again.

	 * gets to run.

	 */

	preempt_disable();

	rcu_read_lock_sched_notrace();



	faultpage = get_kmmio_fault_page(page_base);
@@ -324,7 +323,6 @@ int kmmio_handler(struct pt_regs *regs, unsigned long addr) 


no_kmmio:

	rcu_read_unlock_sched_notrace();

	preempt_enable_no_resched();

	return ret;

}
@@ -364,7 +362,6 @@ static int post_kmmio_handler(unsigned long condition, struct pt_regs *regs) 
	ctx->active--;

	BUG_ON(ctx->active);

	rcu_read_unlock_sched_notrace();

	preempt_enable_no_resched();



	/*

	 * if somebody else is singlestepping across a probe point, flags