[RFC PATCH v2] perf/amd: Try to fix some mem allocation failure handling

From: Zhouyi Zhou
Date: Wed Jun 11 2014 - 00:09:43 EST


According to Peter's advice, put the failure handling to a goto chain.
Compiled in x86_64, could you check if there is anything that I missed.

Signed-off-by: Zhouyi Zhou <yizhouzhou@xxxxxxxxx>
---
arch/x86/kernel/cpu/perf_event_amd_uncore.c | 111 ++++++++++++++++++++-------
1 file changed, 84 insertions(+), 27 deletions(-)

diff --git a/arch/x86/kernel/cpu/perf_event_amd_uncore.c b/arch/x86/kernel/cpu/perf_event_amd_uncore.c
index 3bbdf4c..30790d7 100644
--- a/arch/x86/kernel/cpu/perf_event_amd_uncore.c
+++ b/arch/x86/kernel/cpu/perf_event_amd_uncore.c
@@ -294,31 +294,41 @@ static struct amd_uncore *amd_uncore_alloc(unsigned int cpu)
cpu_to_node(cpu));
}

-static void amd_uncore_cpu_up_prepare(unsigned int cpu)
+static int amd_uncore_cpu_up_prepare(unsigned int cpu)
{
- struct amd_uncore *uncore;
+ struct amd_uncore *uncore_nb = NULL, *uncore_l2;

if (amd_uncore_nb) {
- uncore = amd_uncore_alloc(cpu);
- uncore->cpu = cpu;
- uncore->num_counters = NUM_COUNTERS_NB;
- uncore->rdpmc_base = RDPMC_BASE_NB;
- uncore->msr_base = MSR_F15H_NB_PERF_CTL;
- uncore->active_mask = &amd_nb_active_mask;
- uncore->pmu = &amd_nb_pmu;
- *per_cpu_ptr(amd_uncore_nb, cpu) = uncore;
+ uncore_nb = amd_uncore_alloc(cpu);
+ if (!uncore_nb)
+ goto fail;
+ uncore_nb->cpu = cpu;
+ uncore_nb->num_counters = NUM_COUNTERS_NB;
+ uncore_nb->rdpmc_base = RDPMC_BASE_NB;
+ uncore_nb->msr_base = MSR_F15H_NB_PERF_CTL;
+ uncore_nb->active_mask = &amd_nb_active_mask;
+ uncore_nb->pmu = &amd_nb_pmu;
+ *per_cpu_ptr(amd_uncore_nb, cpu) = uncore_nb;
}

if (amd_uncore_l2) {
- uncore = amd_uncore_alloc(cpu);
- uncore->cpu = cpu;
- uncore->num_counters = NUM_COUNTERS_L2;
- uncore->rdpmc_base = RDPMC_BASE_L2;
- uncore->msr_base = MSR_F16H_L2I_PERF_CTL;
- uncore->active_mask = &amd_l2_active_mask;
- uncore->pmu = &amd_l2_pmu;
- *per_cpu_ptr(amd_uncore_l2, cpu) = uncore;
+ uncore_l2 = amd_uncore_alloc(cpu);
+ if (!uncore_l2)
+ goto fail;
+ uncore_l2->cpu = cpu;
+ uncore_l2->num_counters = NUM_COUNTERS_L2;
+ uncore_l2->rdpmc_base = RDPMC_BASE_L2;
+ uncore_l2->msr_base = MSR_F16H_L2I_PERF_CTL;
+ uncore_l2->active_mask = &amd_l2_active_mask;
+ uncore_l2->pmu = &amd_l2_pmu;
+ *per_cpu_ptr(amd_uncore_l2, cpu) = uncore_l2;
}
+
+ return 0;
+
+fail:
+ kfree(uncore_nb);
+ return -ENOMEM;
}

static struct amd_uncore *
@@ -441,7 +451,7 @@ static void uncore_dead(unsigned int cpu, struct amd_uncore * __percpu *uncores)

if (!--uncore->refcnt)
kfree(uncore);
- *per_cpu_ptr(amd_uncore_nb, cpu) = NULL;
+ *per_cpu_ptr(uncores, cpu) = NULL;
}

static void amd_uncore_cpu_dead(unsigned int cpu)
@@ -461,7 +471,8 @@ amd_uncore_cpu_notifier(struct notifier_block *self, unsigned long action,

switch (action & ~CPU_TASKS_FROZEN) {
case CPU_UP_PREPARE:
- amd_uncore_cpu_up_prepare(cpu);
+ if (amd_uncore_cpu_up_prepare(cpu))
+ return notifier_from_errno(-ENOMEM);
break;

case CPU_STARTING:
@@ -501,20 +512,33 @@ static void __init init_cpu_already_online(void *dummy)
amd_uncore_cpu_online(cpu);
}

+static void cleanup_cpu_online(void *dummy)
+{
+ unsigned int cpu = smp_processor_id();
+
+ amd_uncore_cpu_dead(cpu);
+}
+
static int __init amd_uncore_init(void)
{
- unsigned int cpu;
+ unsigned int cpu, cpu2;
int ret = -ENODEV;

if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD)
- return -ENODEV;
+ goto fail_nodev;

if (!cpu_has_topoext)
- return -ENODEV;
+ goto fail_nodev;

if (cpu_has_perfctr_nb) {
amd_uncore_nb = alloc_percpu(struct amd_uncore *);
- perf_pmu_register(&amd_nb_pmu, amd_nb_pmu.name, -1);
+ if (!amd_uncore_nb) {
+ ret = -ENOMEM;
+ goto fail_nb;
+ }
+ ret = perf_pmu_register(&amd_nb_pmu, amd_nb_pmu.name, -1);
+ if (ret)
+ goto fail_nb;

printk(KERN_INFO "perf: AMD NB counters detected\n");
ret = 0;
@@ -522,20 +546,28 @@ static int __init amd_uncore_init(void)

if (cpu_has_perfctr_l2) {
amd_uncore_l2 = alloc_percpu(struct amd_uncore *);
- perf_pmu_register(&amd_l2_pmu, amd_l2_pmu.name, -1);
+ if (!amd_uncore_l2) {
+ ret = -ENOMEM;
+ goto fail_l2;
+ }
+ ret = perf_pmu_register(&amd_l2_pmu, amd_l2_pmu.name, -1);
+ if (ret)
+ goto fail_l2;

printk(KERN_INFO "perf: AMD L2I counters detected\n");
ret = 0;
}

if (ret)
- return -ENODEV;
+ goto fail_nodev;

cpu_notifier_register_begin();

/* init cpus already online before registering for hotplug notifier */
for_each_online_cpu(cpu) {
- amd_uncore_cpu_up_prepare(cpu);
+ ret = amd_uncore_cpu_up_prepare(cpu);
+ if (ret)
+ goto fail_online;
smp_call_function_single(cpu, init_cpu_already_online, NULL, 1);
}

@@ -543,5 +575,30 @@ static int __init amd_uncore_init(void)
cpu_notifier_register_done();

return 0;
+
+
+fail_online:
+ for_each_online_cpu(cpu2) {
+ if (cpu2 == cpu)
+ break;
+ smp_call_function_single(cpu, cleanup_cpu_online, NULL, 1);
+ }
+ cpu_notifier_register_done();
+
+ /* amd_uncore_nb/l2 should have been freed by cleanup_cpu_online */
+ amd_uncore_nb = amd_uncore_l2 = NULL;
+ if (cpu_has_perfctr_l2)
+ perf_pmu_unregister(&amd_l2_pmu);
+fail_l2:
+ if (cpu_has_perfctr_nb)
+ perf_pmu_unregister(&amd_nb_pmu);
+ if (amd_uncore_l2)
+ free_percpu(amd_uncore_l2);
+fail_nb:
+ if (amd_uncore_nb)
+ free_percpu(amd_uncore_nb);
+
+fail_nodev:
+ return ret;
}
device_initcall(amd_uncore_init);
--
1.7.10.4

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