+ watchdog-buddy-dont-copy-the-cpumask-in-watchdog_next_cpu.patch added to mm-nonmm-unstable branch

+ watchdog-buddy-dont-copy-the-cpumask-in-watchdog_next_cpu.patch added to mm-nonmm-unstable branch

[Andrew Morton]

The patch titled
     Subject: watchdog/buddy: don't copy the cpumask in watchdog_next_cpu()
has been added to the -mm mm-nonmm-unstable branch.  Its filename is
     watchdog-buddy-dont-copy-the-cpumask-in-watchdog_next_cpu.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/watchdog-buddy-dont-copy-the-cpumask-in-watchdog_next_cpu.patch

This patch will later appear in the mm-nonmm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Douglas Anderson <dianders@chromium.org>
Subject: watchdog/buddy: don't copy the cpumask in watchdog_next_cpu()
Date: Fri, 26 May 2023 18:41:37 -0700

There's no reason to make a copy of the "watchdog_cpus" locally in
watchdog_next_cpu().  Making a copy wouldn't make things any more race
free and we're just reading the value so there's no need for a copy.

Link: https://lkml.kernel.org/r/20230526184139.7.If466f9a2b50884cbf6a1d8ad05525a2c17069407@changeid
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Suggested-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 kernel/watchdog_buddy.c |    5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

--- a/kernel/watchdog_buddy.c~watchdog-buddy-dont-copy-the-cpumask-in-watchdog_next_cpu
+++ a/kernel/watchdog_buddy.c
@@ -10,12 +10,11 @@ static cpumask_t __read_mostly watchdog_
 
 static unsigned int watchdog_next_cpu(unsigned int cpu)
 {
-	cpumask_t cpus = watchdog_cpus;
 	unsigned int next_cpu;
 
-	next_cpu = cpumask_next(cpu, &cpus);
+	next_cpu = cpumask_next(cpu, &watchdog_cpus);
 	if (next_cpu >= nr_cpu_ids)
-		next_cpu = cpumask_first(&cpus);
+		next_cpu = cpumask_first(&watchdog_cpus);
 
 	if (next_cpu == cpu)
 		return nr_cpu_ids;
_

Patches currently in -mm which might be from dianders@chromium.org are

migrate_pages-avoid-blocking-for-io-in-migrate_sync_light.patch
watchdog-perf-define-dummy-watchdog_update_hrtimer_threshold-on-correct-config.patch
watchdog-perf-more-properly-prevent-false-positives-with-turbo-modes.patch
watchdog-hardlockup-add-comments-to-touch_nmi_watchdog.patch
watchdog-perf-rename-watchdog_hldc-to-watchdog_perfc.patch
watchdog-hardlockup-move-perf-hardlockup-checking-panic-to-common-watchdogc.patch
watchdog-hardlockup-style-changes-to-watchdog_hardlockup_check-is_hardlockup.patch
watchdog-hardlockup-add-a-cpu-param-to-watchdog_hardlockup_check.patch
watchdog-hardlockup-move-perf-hardlockup-watchdog-petting-to-watchdogc.patch
watchdog-hardlockup-rename-some-nmi-watchdog-constants-function.patch
watchdog-hardlockup-have-the-perf-hardlockup-use-__weak-functions-more-cleanly.patch
watchdog-hardlockup-detect-hard-lockups-using-secondary-buddy-cpus.patch
watchdog-perf-add-a-weak-function-for-an-arch-to-detect-if-perf-can-use-nmis.patch
arm64-enable-perf-events-based-hard-lockup-detector.patch
arm64-enable-perf-events-based-hard-lockup-detector-fix.patch
watchdog-hardlockup-keep-kernelnmi_watchdog-sysctl-as-0444-if-probe-fails.patch
watchdog-hardlockup-have_nmi_watchdog-must-implement-watchdog_hardlockup_probe.patch
watchdog-hardlockup-dont-use-raw_cpu_ptr-in-watchdog_hardlockup_kick.patch
watchdog-hardlockup-in-watchdog_hardlockup_check-use-cpumask_copy.patch
watchdog-hardlockup-remove-softlockup-comment-in-touch_nmi_watchdog.patch
watchdog-buddy-cleanup-how-watchdog_buddy_check_hardlockup-is-called.patch
watchdog-buddy-dont-copy-the-cpumask-in-watchdog_next_cpu.patch
watchdog-buddy-simplify-the-dependency-for-hardlockup_detector_prefer_buddy.patch
watchdog-hardlockup-move-smp-barriers-from-common-code-to-buddy-code.patch
watchdog-hardlockup-rename-have_hardlockup_detector_non_arch-to-_perf_or_buddy.patch