[patch 29/29] lockup_detector: Cleanup hotplug locking mess
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SUPERSEDED
From: Thomas Gleixner <hidden>
Date: 2017-08-31 07:32:08
Also in:
lkml
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Linus Torvalds
Status: Superseded by v2 (posted 2017-09-12). [go to v2]
Revision v1 (2 revisions archived).
Revisions (2)
- v1 current
- v2 [diff against previous]
All watchdog thread related functions are delegated to the smpboot thread infrastructure, which handles serialization against CPU hotplug correctly. The sysctl interface is completely decoupled from anything which requires CPU hotplug protection. No need to protect the sysctl writes against cpu hotplug anymore. Remove it and add the now required protection to the powerpc arch_nmi_watchdog implementation. Signed-off-by: Thomas Gleixner <redacted> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: <redacted> --- arch/powerpc/kernel/watchdog.c | 2 ++ kernel/watchdog.c | 6 ------ 2 files changed, 2 insertions(+), 6 deletions(-)
--- a/arch/powerpc/kernel/watchdog.c
+++ b/arch/powerpc/kernel/watchdog.c@@ -356,6 +356,7 @@ void watchdog_nmi_reconfigure(bool stop) { int cpu; + cpus_read_lock(); if (stop) { for_each_cpu(cpu, &wd_cpus_enabled) stop_wd_on_cpu(cpu);
@@ -364,6 +365,7 @@ void watchdog_nmi_reconfigure(bool stop) for_each_cpu_and(cpu, cpu_online_mask, &watchdog_cpumask) start_wd_on_cpu(cpu); } + cpus_read_unlock(); } /* --- a/kernel/watchdog.c +++ b/kernel/watchdog.c
@@ -652,7 +652,6 @@ static int proc_watchdog_common(int whic { int err, old, *param = table->data; - cpu_hotplug_disable(); mutex_lock(&watchdog_mutex); if (!write) {
@@ -669,7 +668,6 @@ static int proc_watchdog_common(int whic proc_watchdog_update(); } mutex_unlock(&watchdog_mutex); - cpu_hotplug_enable(); return err; }
@@ -713,7 +711,6 @@ int proc_watchdog_thresh(struct ctl_tabl { int err, old; - cpu_hotplug_disable(); mutex_lock(&watchdog_mutex); old = READ_ONCE(watchdog_thresh);
@@ -723,7 +720,6 @@ int proc_watchdog_thresh(struct ctl_tabl proc_watchdog_update(); mutex_unlock(&watchdog_mutex); - cpu_hotplug_enable(); return err; }
@@ -738,7 +734,6 @@ int proc_watchdog_cpumask(struct ctl_tab { int err; - cpu_hotplug_disable(); mutex_lock(&watchdog_mutex); err = proc_do_large_bitmap(table, write, buffer, lenp, ppos);
@@ -746,7 +741,6 @@ int proc_watchdog_cpumask(struct ctl_tab proc_watchdog_update(); mutex_unlock(&watchdog_mutex); - cpu_hotplug_enable(); return err; } #endif /* CONFIG_SYSCTL */