perf/x86/intel/uncore: Clean up hotplug conversion fallout

The recent conversion to the hotplug state machine kept two mechanisms from
the original code:

 1) The first_init logic which adds the number of online CPUs in a package
    to the refcount. That's wrong because the callbacks are executed for
    all online CPUs.

    Remove it so the refcounting is correct.

 2) The on_each_cpu() call to undo box->init() in the error handling
    path. That's bogus because when the prepare callback fails no box has
    been initialized yet.

    Remove it.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Stephane Eranian <eranian@google.com>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: Yasuaki Ishimatsu <yasu.isimatu@gmail.com>
Fixes: 1a246b9f58c6 ("perf/x86/intel/uncore: Convert to hotplug state machine")
Link: http://lkml.kernel.org/r/20170131230141.298032324@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/x86/events/intel/uncore.c b/arch/x86/events/intel/uncore.c
index 8c4ccdc3a3f3607ee0af4f4006029df3000e0839..56c5235dcc29f573cafbc0050c3ede94ac590bbf 100644 (file)
--- a/arch/x86/events/intel/uncore.c
+++ b/arch/x86/events/intel/uncore.c
@@ -764,30 +764,6 @@ static void uncore_pmu_unregister(struct intel_uncore_pmu *pmu)
        pmu->registered = false;
 }
 
-static void __uncore_exit_boxes(struct intel_uncore_type *type, int cpu)
-{
-       struct intel_uncore_pmu *pmu = type->pmus;
-       struct intel_uncore_box *box;
-       int i, pkg;
-
-       if (pmu) {
-               pkg = topology_physical_package_id(cpu);
-               for (i = 0; i < type->num_boxes; i++, pmu++) {
-                       box = pmu->boxes[pkg];
-                       if (box)
-                               uncore_box_exit(box);
-               }
-       }
-}
-
-static void uncore_exit_boxes(void *dummy)
-{
-       struct intel_uncore_type **types;
-
-       for (types = uncore_msr_uncores; *types; types++)
-               __uncore_exit_boxes(*types++, smp_processor_id());
-}
-
 static void uncore_free_boxes(struct intel_uncore_pmu *pmu)
 {
        int pkg;
@@ -1078,22 +1054,12 @@ static int uncore_cpu_dying(unsigned int cpu)
        return 0;
 }
 
-static int first_init;
-
 static int uncore_cpu_starting(unsigned int cpu)
 {
        struct intel_uncore_type *type, **types = uncore_msr_uncores;
        struct intel_uncore_pmu *pmu;
        struct intel_uncore_box *box;
-       int i, pkg, ncpus = 1;
-
-       if (first_init) {
-               /*
-                * On init we get the number of online cpus in the package
-                * and set refcount for all of them.
-                */
-               ncpus = cpumask_weight(topology_core_cpumask(cpu));
-       }
+       int i, pkg;
 
        pkg = topology_logical_package_id(cpu);
        for (; *types; types++) {
@@ -1104,7 +1070,7 @@ static int uncore_cpu_starting(unsigned int cpu)
                        if (!box)
                                continue;
                        /* The first cpu on a package activates the box */
-                       if (atomic_add_return(ncpus, &box->refcnt) == ncpus)
+                       if (atomic_inc_return(&box->refcnt) == 1)
                                uncore_box_init(box);
                }
        }
@@ -1408,19 +1374,17 @@ static int __init intel_uncore_init(void)
                                          "perf/x86/intel/uncore:prepare",
                                          uncore_cpu_prepare, NULL);
        }
-       first_init = 1;
+
        cpuhp_setup_state(CPUHP_AP_PERF_X86_UNCORE_STARTING,
                          "perf/x86/uncore:starting",
                          uncore_cpu_starting, uncore_cpu_dying);
-       first_init = 0;
+
        cpuhp_setup_state(CPUHP_AP_PERF_X86_UNCORE_ONLINE,
                          "perf/x86/uncore:online",
                          uncore_event_cpu_online, uncore_event_cpu_offline);
        return 0;
 
 err:
-       /* Undo box->init_box() */
-       on_each_cpu_mask(&uncore_cpu_mask, uncore_exit_boxes, NULL, 1);
        uncore_types_exit(uncore_msr_uncores);
        uncore_pci_exit();
        return ret;