From 4211b51f6e95484d86eaa5071e50f33ab95540b0 Mon Sep 17 00:00:00 2001
From: Mark Rutland <mark.rutland@arm.com>
Date: Mon, 5 Feb 2018 16:41:58 +0000
Subject: [PATCH 055/105] arm_pmu: add armpmu_alloc_atomic()

Git-commit: 0dc1a1851af1d593eee248b94c1277c7c7ccbbce
Patch-mainline: v4.16-rc3
References: fate#325865,fate#325861

In ACPI systems, we don't know the makeup of CPUs until we hotplug them
on, and thus have to allocate the PMU datastructures at hotplug time.
Thus, we must use GFP_ATOMIC allocations.

Let's add an armpmu_alloc_atomic() that we can use in this case.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Mian Yousaf Kaukab <yousaf.kaukab@suse.com>
---
 drivers/perf/arm_pmu.c       | 17 ++++++++++++++---
 drivers/perf/arm_pmu_acpi.c  |  2 +-
 include/linux/perf/arm_pmu.h |  1 +
 3 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c
index 373dfd7d8a1d..4f73c5e8d623 100644
--- a/drivers/perf/arm_pmu.c
+++ b/drivers/perf/arm_pmu.c
@@ -760,18 +760,18 @@ static void cpu_pmu_destroy(struct arm_pmu *cpu_pmu)
 					    &cpu_pmu->node);
 }
 
-struct arm_pmu *armpmu_alloc(void)
+static struct arm_pmu *__armpmu_alloc(gfp_t flags)
 {
 	struct arm_pmu *pmu;
 	int cpu;
 
-	pmu = kzalloc(sizeof(*pmu), GFP_KERNEL);
+	pmu = kzalloc(sizeof(*pmu), flags);
 	if (!pmu) {
 		pr_info("failed to allocate PMU device!\n");
 		goto out;
 	}
 
-	pmu->hw_events = alloc_percpu(struct pmu_hw_events);
+	pmu->hw_events = alloc_percpu_gfp(struct pmu_hw_events, flags);
 	if (!pmu->hw_events) {
 		pr_info("failed to allocate per-cpu PMU data.\n");
 		goto out_free_pmu;
@@ -817,6 +817,17 @@ struct arm_pmu *armpmu_alloc(void)
 	return NULL;
 }
 
+struct arm_pmu *armpmu_alloc(void)
+{
+	return __armpmu_alloc(GFP_KERNEL);
+}
+
+struct arm_pmu *armpmu_alloc_atomic(void)
+{
+	return __armpmu_alloc(GFP_ATOMIC);
+}
+
+
 void armpmu_free(struct arm_pmu *pmu)
 {
 	free_percpu(pmu->hw_events);
diff --git a/drivers/perf/arm_pmu_acpi.c b/drivers/perf/arm_pmu_acpi.c
index 705f1a390e31..30c5f2bbce59 100644
--- a/drivers/perf/arm_pmu_acpi.c
+++ b/drivers/perf/arm_pmu_acpi.c
@@ -127,7 +127,7 @@ static struct arm_pmu *arm_pmu_acpi_find_alloc_pmu(void)
 		return pmu;
 	}
 
-	pmu = armpmu_alloc();
+	pmu = armpmu_alloc_atomic();
 	if (!pmu) {
 		pr_warn("Unable to allocate PMU for CPU%d\n",
 			smp_processor_id());
diff --git a/include/linux/perf/arm_pmu.h b/include/linux/perf/arm_pmu.h
index 899bc7ef0881..1f8bb83ef42f 100644
--- a/include/linux/perf/arm_pmu.h
+++ b/include/linux/perf/arm_pmu.h
@@ -157,6 +157,7 @@ static inline int arm_pmu_acpi_probe(armpmu_init_fn init_fn) { return 0; }
 
 /* Internal functions only for core arm_pmu code */
 struct arm_pmu *armpmu_alloc(void);
+struct arm_pmu *armpmu_alloc_atomic(void);
 void armpmu_free(struct arm_pmu *pmu);
 int armpmu_register(struct arm_pmu *pmu);
 int armpmu_request_irq(struct arm_pmu *armpmu, int cpu);
-- 
2.11.0