hw_breakpoint: Simplify the "weight" usage in toggle_bp_slot() paths

Change toggle_bp_slot() to make "weight" negative if !enable.
This way we can always use "+ weight" without additional "if
(enable)" check and toggle_bp_task_slot() no longer needs this
arg.

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/20130620155013.GA6337@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/kernel/events/hw_breakpoint.c b/kernel/events/hw_breakpoint.c
index dee0148dcf543a59c01f575d50d74670915cd0bb..5cd4f6d9652c18104b9272ea8deeb9f680dcfe9b 100644 (file)
--- a/kernel/events/hw_breakpoint.c
+++ b/kernel/events/hw_breakpoint.c
@@ -182,7 +182,7 @@ fetch_this_slot(struct bp_busy_slots *slots, int weight)
 /*
  * Add a pinned breakpoint for the given task in our constraint table
  */
-static void toggle_bp_task_slot(struct perf_event *bp, int cpu, bool enable,
+static void toggle_bp_task_slot(struct perf_event *bp, int cpu,
                                enum bp_type_idx type, int weight)
 {
        /* tsk_pinned[n-1] is the number of tasks having n>0 breakpoints */
@@ -190,10 +190,7 @@ static void toggle_bp_task_slot(struct perf_event *bp, int cpu, bool enable,
        int old_idx, new_idx;
 
        old_idx = task_bp_pinned(cpu, bp, type) - 1;
-       if (enable)
-               new_idx = old_idx + weight;
-       else
-               new_idx = old_idx - weight;
+       new_idx = old_idx + weight;
 
        if (old_idx >= 0)
                tsk_pinned[old_idx]--;
@@ -211,22 +208,21 @@ toggle_bp_slot(struct perf_event *bp, bool enable, enum bp_type_idx type,
        int cpu = bp->cpu;
        struct task_struct *tsk = bp->hw.bp_target;
 
+       if (!enable)
+               weight = -weight;
+
        /* Pinned counter cpu profiling */
        if (!tsk) {
-
-               if (enable)
-                       per_cpu(nr_cpu_bp_pinned[type], bp->cpu) += weight;
-               else
-                       per_cpu(nr_cpu_bp_pinned[type], bp->cpu) -= weight;
+               per_cpu(nr_cpu_bp_pinned[type], cpu) += weight;
                return;
        }
 
        /* Pinned counter task profiling */
        if (cpu >= 0) {
-               toggle_bp_task_slot(bp, cpu, enable, type, weight);
+               toggle_bp_task_slot(bp, cpu, type, weight);
        } else {
                for_each_possible_cpu(cpu)
-                       toggle_bp_task_slot(bp, cpu, enable, type, weight);
+                       toggle_bp_task_slot(bp, cpu, type, weight);
        }
 
        if (enable)