[PATCH V3 2/2] bpf: control all the perf events stored in PERF_EVENT_ARRAY maps

[Kaixu Xia]

This patch implements the function that controlling all the perf
events stored in PERF_EVENT_ARRAY maps by setting the parameter
'index' to maps max_entries.

Signed-off-by: Kaixu Xia <xiaka...@huawei.com>
---
 kernel/trace/bpf_trace.c | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 3175600..4b385863 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -229,13 +229,30 @@ static u64 bpf_perf_event_dump_control(u64 r1, u64 index, 
u64 flag, u64 r4, u64
        struct bpf_map *map = (struct bpf_map *) (unsigned long) r1;
        struct bpf_array *array = container_of(map, struct bpf_array, map);
        struct perf_event *event;
+       int i;
 
-       if (unlikely(index >= array->map.max_entries))
+       if (unlikely(index > array->map.max_entries))
                return -E2BIG;
 
        if (flag & BIT_FLAG_CHECK)
                return -EINVAL;
 
+       if (index == array->map.max_entries) {
+               bool dump_control = flag & BIT_DUMP_CTL;
+
+               for (i = 0; i < array->map.max_entries; i++) {
+                       event = (struct perf_event *)array->ptrs[i];
+                       if (!event)
+                               continue;
+
+                       if (dump_control)
+                               atomic_dec_if_positive(&event->dump_enable);
+                       else
+                               atomic_inc_unless_negative(&event->dump_enable);
+               }
+               return 0;
+       }
+
        event = (struct perf_event *)array->ptrs[index];
        if (!event)
                return -ENOENT;
@@ -244,7 +261,6 @@ static u64 bpf_perf_event_dump_control(u64 r1, u64 index, 
u64 flag, u64 r4, u64
                atomic_dec_if_positive(&event->dump_enable);
        else
                atomic_inc_unless_negative(&event->dump_enable);
-
        return 0;
 }
 
-- 
1.8.3.4

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html