perf/x86/amd: Try to fix some mem allocation failure handling

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@ict.ac.cn>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1402459743-20513-1-git-send-email-zhouzhouyi@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files 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 3bbdf4cd38b9..30790d798e6b 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);