hw-breakpoints: Use overflow handler instead of the event callback

struct perf_event::event callback was called when a breakpoint
triggers. But this is a rather opaque callback, pretty
tied-only to the breakpoint API and not really integrated into perf
as it triggers even when we don't overflow.

We prefer to use overflow_handler() as it fits into the perf events
rules, being called only when we overflow.

Reported-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: "K. Prasad" <prasad@linux.vnet.ibm.com>

1 files changed, 7 insertions, 6 deletions

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 84bd28a0ffab..d2f2667430da 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -565,10 +565,13 @@ struct perf_pending_entry {
         void (*func)(struct perf_pending_entry *);
 };
 
-typedef void (*perf_callback_t)(struct perf_event *, void *);
-
 struct perf_sample_data;
 
+typedef void (*perf_callback_t)(struct perf_event *, void *);
+typedef void (*perf_overflow_handler_t)(struct perf_event *, int,
+                                        struct perf_sample_data *,
+                                        struct pt_regs *regs);
+
 /**
  * struct perf_event - performance event kernel representation:
  */
@@ -660,9 +663,7 @@ struct perf_event {
         struct pid_namespace            *ns;
         u64                             id;
 
-        void (*overflow_handler)(struct perf_event *event,
-                        int nmi, struct perf_sample_data *data,
-                        struct pt_regs *regs);
+        perf_overflow_handler_t         overflow_handler;
 
 #ifdef CONFIG_EVENT_PROFILE
         struct event_filter             *filter;
@@ -779,7 +780,7 @@ extern struct perf_event *
 perf_event_create_kernel_counter(struct perf_event_attr *attr,
                                 int cpu,
                                 pid_t pid,
-                                perf_callback_t callback);
+                                perf_overflow_handler_t callback);
 extern u64 perf_event_read_value(struct perf_event *event,
                                  u64 *enabled, u64 *running);