From 67d35cc1d37f33c3097957451da57bb6a3802531 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alessandro=C2=A0Decina?= <alessandro.d@gmail.com>
Date: Thu, 10 Jun 2021 07:43:41 +0000
Subject: [PATCH] bpf: fix PerfMap::output() API when appending context data

map.output(&ctx, &data, nr_bytes) can be used to append nr_bytes from
the current context to the &data event.
---
 bpf/aya-bpf/src/maps/perf_map.rs | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/bpf/aya-bpf/src/maps/perf_map.rs b/bpf/aya-bpf/src/maps/perf_map.rs
index b625e77c..212e2433 100644
--- a/bpf/aya-bpf/src/maps/perf_map.rs
+++ b/bpf/aya-bpf/src/maps/perf_map.rs
@@ -32,8 +32,8 @@ impl<T> PerfMap<T> {
         }
     }
 
-    pub fn output<C: BpfContext>(&mut self, ctx: &C, data: &T) {
-        self.output_at_index(ctx, None, data, 0)
+    pub fn output<C: BpfContext>(&mut self, ctx: &C, data: &T, flags: u32) {
+        self.output_at_index(ctx, None, data, flags)
     }
 
     pub fn output_at_index<C: BpfContext>(
@@ -43,10 +43,8 @@ impl<T> PerfMap<T> {
         data: &T,
         flags: u32,
     ) {
-        let index = index
-            .map(|i| (i as u64) << 32)
-            .unwrap_or(BPF_F_CURRENT_CPU.into());
-        let flags = index | flags as u64;
+        let index = index.unwrap_or(BPF_F_CURRENT_CPU.into()) as u64;
+        let flags = (flags as u64) << 32 | index;
         unsafe {
             bpf_perf_event_output(
                 ctx.as_ptr(),