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>

1 files changed, 8 insertions, 12 deletions

diff --git a/kernel/events/hw_breakpoint.c b/kernel/events/hw_breakpoint.c
index dee0148dcf54..5cd4f6d9652c 100644
--- 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)