hw_breakpoint: Introduce cpumask_of_bp()

Add the trivial helper which simply returns cpumask_of() or
cpu_possible_mask depending on bp->cpu.

Change fetch_bp_busy_slots() and toggle_bp_slot() to always do
for_each_cpu(cpumask_of_bp) to simplify the code and avoid the
code duplication.

Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/r/20130620155015.GA6340@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 17 insertions, 26 deletions

diff --git a/kernel/events/hw_breakpoint.c b/kernel/events/hw_breakpoint.c
index 5cd4f6d9652c..9c71445328af 100644
--- a/kernel/events/hw_breakpoint.c
+++ b/kernel/events/hw_breakpoint.c
@@ -127,6 +127,13 @@ static int task_bp_pinned(int cpu, struct perf_event *bp, enum bp_type_idx type)
         return count;
 }
 
+static const struct cpumask *cpumask_of_bp(struct perf_event *bp)
+{
+        if (bp->cpu >= 0)
+                return cpumask_of(bp->cpu);
+        return cpu_possible_mask;
+}
+
 /*
  * Report the number of pinned/un-pinned breakpoints we have in
  * a given cpu (cpu > -1) or in all of them (cpu = -1).
@@ -135,25 +142,13 @@ static void
 fetch_bp_busy_slots(struct bp_busy_slots *slots, struct perf_event *bp,
                     enum bp_type_idx type)
 {
-        int cpu = bp->cpu;
-        struct task_struct *tsk = bp->hw.bp_target;
-
-        if (cpu >= 0) {
-                slots->pinned = per_cpu(nr_cpu_bp_pinned[type], cpu);
-                if (!tsk)
-                        slots->pinned += max_task_bp_pinned(cpu, type);
-                else
-                        slots->pinned += task_bp_pinned(cpu, bp, type);
-                slots->flexible = per_cpu(nr_bp_flexible[type], cpu);
-
-                return;
-        }
+        const struct cpumask *cpumask = cpumask_of_bp(bp);
+        int cpu;
 
-        for_each_possible_cpu(cpu) {
-                unsigned int nr;
+        for_each_cpu(cpu, cpumask) {
+                unsigned int nr = per_cpu(nr_cpu_bp_pinned[type], cpu);
 
-                nr = per_cpu(nr_cpu_bp_pinned[type], cpu);
-                if (!tsk)
+                if (!bp->hw.bp_target)
                         nr += max_task_bp_pinned(cpu, type);
                 else
                         nr += task_bp_pinned(cpu, bp, type);
@@ -205,25 +200,21 @@ static void
 toggle_bp_slot(struct perf_event *bp, bool enable, enum bp_type_idx type,
                int weight)
 {
-        int cpu = bp->cpu;
-        struct task_struct *tsk = bp->hw.bp_target;
+        const struct cpumask *cpumask = cpumask_of_bp(bp);
+        int cpu;
 
         if (!enable)
                 weight = -weight;
 
         /* Pinned counter cpu profiling */
-        if (!tsk) {
-                per_cpu(nr_cpu_bp_pinned[type], cpu) += weight;
+        if (!bp->hw.bp_target) {
+                per_cpu(nr_cpu_bp_pinned[type], bp->cpu) += weight;
                 return;
         }
 
         /* Pinned counter task profiling */
-        if (cpu >= 0) {
+        for_each_cpu(cpu, cpumask)
                 toggle_bp_task_slot(bp, cpu, type, weight);
-        } else {
-                for_each_possible_cpu(cpu)
-                        toggle_bp_task_slot(bp, cpu, type, weight);
-        }
 
         if (enable)
                 list_add_tail(&bp->hw.bp_list, &bp_task_head);