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authorLinus Torvalds <torvalds@linux-foundation.org>2017-07-03 18:08:06 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-07-03 18:08:06 -0700
commit9a9594efe54324e9124add7e7b1e7bdb6d0b08a3 (patch)
tree4544014bf1c214c9c004fe0a64ac78eaa6232cfe /drivers/acpi
parent3ad918e65d6926490c8f18a157cea25bf29ecd3a (diff)
parent993647a293814dd47ae41d38657fda6e4ab04e33 (diff)
downloadlinux-9a9594efe54324e9124add7e7b1e7bdb6d0b08a3.tar.bz2
Merge branch 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull SMP hotplug updates from Thomas Gleixner: "This update is primarily a cleanup of the CPU hotplug locking code. The hotplug locking mechanism is an open coded RWSEM, which allows recursive locking. The main problem with that is the recursive nature as it evades the full lockdep coverage and hides potential deadlocks. The rework replaces the open coded RWSEM with a percpu RWSEM and establishes full lockdep coverage that way. The bulk of the changes fix up recursive locking issues and address the now fully reported potential deadlocks all over the place. Some of these deadlocks have been observed in the RT tree, but on mainline the probability was low enough to hide them away." * 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (37 commits) cpu/hotplug: Constify attribute_group structures powerpc: Only obtain cpu_hotplug_lock if called by rtasd ARM/hw_breakpoint: Fix possible recursive locking for arch_hw_breakpoint_init cpu/hotplug: Remove unused check_for_tasks() function perf/core: Don't release cred_guard_mutex if not taken cpuhotplug: Link lock stacks for hotplug callbacks acpi/processor: Prevent cpu hotplug deadlock sched: Provide is_percpu_thread() helper cpu/hotplug: Convert hotplug locking to percpu rwsem s390: Prevent hotplug rwsem recursion arm: Prevent hotplug rwsem recursion arm64: Prevent cpu hotplug rwsem recursion kprobes: Cure hotplug lock ordering issues jump_label: Reorder hotplug lock and jump_label_lock perf/tracing/cpuhotplug: Fix locking order ACPI/processor: Use cpu_hotplug_disable() instead of get_online_cpus() PCI: Replace the racy recursion prevention PCI: Use cpu_hotplug_disable() instead of get_online_cpus() perf/x86/intel: Drop get_online_cpus() in intel_snb_check_microcode() x86/perf: Drop EXPORT of perf_check_microcode ...
Diffstat (limited to 'drivers/acpi')
-rw-r--r--drivers/acpi/processor_driver.c4
-rw-r--r--drivers/acpi/processor_throttling.c16
2 files changed, 10 insertions, 10 deletions
diff --git a/drivers/acpi/processor_driver.c b/drivers/acpi/processor_driver.c
index 8697a82bd465..591d1dd3f04e 100644
--- a/drivers/acpi/processor_driver.c
+++ b/drivers/acpi/processor_driver.c
@@ -268,9 +268,9 @@ static int acpi_processor_start(struct device *dev)
return -ENODEV;
/* Protect against concurrent CPU hotplug operations */
- get_online_cpus();
+ cpu_hotplug_disable();
ret = __acpi_processor_start(device);
- put_online_cpus();
+ cpu_hotplug_enable();
return ret;
}
diff --git a/drivers/acpi/processor_throttling.c b/drivers/acpi/processor_throttling.c
index 3de34633f7f9..7f9aff4b8d62 100644
--- a/drivers/acpi/processor_throttling.c
+++ b/drivers/acpi/processor_throttling.c
@@ -909,6 +909,13 @@ static long __acpi_processor_get_throttling(void *data)
return pr->throttling.acpi_processor_get_throttling(pr);
}
+static int call_on_cpu(int cpu, long (*fn)(void *), void *arg, bool direct)
+{
+ if (direct || (is_percpu_thread() && cpu == smp_processor_id()))
+ return fn(arg);
+ return work_on_cpu(cpu, fn, arg);
+}
+
static int acpi_processor_get_throttling(struct acpi_processor *pr)
{
if (!pr)
@@ -926,7 +933,7 @@ static int acpi_processor_get_throttling(struct acpi_processor *pr)
if (!cpu_online(pr->id))
return -ENODEV;
- return work_on_cpu(pr->id, __acpi_processor_get_throttling, pr);
+ return call_on_cpu(pr->id, __acpi_processor_get_throttling, pr, false);
}
static int acpi_processor_get_fadt_info(struct acpi_processor *pr)
@@ -1076,13 +1083,6 @@ static long acpi_processor_throttling_fn(void *data)
arg->target_state, arg->force);
}
-static int call_on_cpu(int cpu, long (*fn)(void *), void *arg, bool direct)
-{
- if (direct)
- return fn(arg);
- return work_on_cpu(cpu, fn, arg);
-}
-
static int __acpi_processor_set_throttling(struct acpi_processor *pr,
int state, bool force, bool direct)
{