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

commit 1aa6cfd33df492939b0be15ebdbcff1f8ae5ddb6 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 4 insertions, 40 deletions

diff --git a/arch/x86/events/intel/uncore.c b/arch/x86/events/intel/uncore.c
index dbaaf7dc8373..19d646a783fd 100644
--- a/arch/x86/events/intel/uncore.c
+++ b/arch/x86/events/intel/uncore.c
@@ -763,30 +763,6 @@ 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;
@@ -1077,22 +1053,12 @@ 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++) {
@@ -1103,7 +1069,7 @@ 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);
                 }
         }
@@ -1407,19 +1373,17 @@ static int __init intel_uncore_init(void)
                                           "PERF_X86_UNCORE_PREP",
                                           uncore_cpu_prepare, NULL);
         }
-        first_init = 1;
+
         cpuhp_setup_state(CPUHP_AP_PERF_X86_UNCORE_STARTING,
                           "AP_PERF_X86_UNCORE_STARTING",
                           uncore_cpu_starting, uncore_cpu_dying);
-        first_init = 0;
+
         cpuhp_setup_state(CPUHP_AP_PERF_X86_UNCORE_ONLINE,
                           "AP_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;