Commit 51d4052b authored Sep 12, 2017 by Thomas Gleixner Committed by Ingo Molnar Sep 14, 2017

watchdog/sysctl: Get rid of the #ifdeffery



The sysctl of the nmi_watchdog file prevents writes by setting:

    min = max = 0

if none of the users is enabled. That involves ifdeffery and is competely
non obvious.

If none of the facilities is enabeld, then the file can simply be made read
only. Move the ifdeffery into the header and use a constant for file
permissions.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Don Zickus <dzickus@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Ulrich Obergfell <uobergfe@redhat.com>
Link: http://lkml.kernel.org/r/20170912194147.706073616@linutronix.de


Signed-off-by: Ingo Molnar <mingo@kernel.org>

parent 3b371b59

include/linux/nmi.h

+6 −0

Original line number	Diff line number	Diff line
		@@ -81,6 +81,12 @@ extern unsigned int hardlockup_panic;
		static inline void hardlockup_detector_disable(void) {}
		#endif

		#if defined(CONFIG_HAVE_NMI_WATCHDOG) \|\| defined(CONFIG_HARDLOCKUP_DETECTOR)
		# define NMI_WATCHDOG_SYSCTL_PERM 0644
		#else
		# define NMI_WATCHDOG_SYSCTL_PERM 0444
		#endif

		#if defined(CONFIG_HARDLOCKUP_DETECTOR_PERF)
		extern void arch_touch_nmi_watchdog(void);
		extern void hardlockup_detector_perf_stop(void);

kernel/sysctl.c

+1 −5

Original line number	Diff line number	Diff line
		@@ -891,14 +891,10 @@ static struct ctl_table kern_table[] = {
		.procname = "nmi_watchdog",
		.data = &nmi_watchdog_enabled,
		.maxlen = sizeof (int),
		.mode = 0644,
		.mode = NMI_WATCHDOG_SYSCTL_PERM,
		.proc_handler = proc_nmi_watchdog,
		.extra1 = &zero,
		#if defined(CONFIG_HAVE_NMI_WATCHDOG) \|\| defined(CONFIG_HARDLOCKUP_DETECTOR)
		.extra2 = &one,
		#else
		.extra2 = &zero,
		#endif
		},
		{
		.procname = "watchdog_cpumask",

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