bpf, samples: don't zero data when not needed

[linux-2.6-microblaze.git] / samples / bpf / offwaketime_kern.c

diff --git a/samples/bpf/offwaketime_kern.c b/samples/bpf/offwaketime_kern.c
index 983629a..e7d9a0a 100644 (file)
--- a/samples/bpf/offwaketime_kern.c
+++ b/samples/bpf/offwaketime_kern.c
@@ -11,7 +11,7 @@
 #include <linux/version.h>
 #include <linux/sched.h>
 
-#define _(P) ({typeof(P) val = 0; bpf_probe_read(&val, sizeof(val), &P); val;})
+#define _(P) ({typeof(P) val; bpf_probe_read(&val, sizeof(val), &P); val;})
 
 #define MINBLOCK_US    1
 
@@ -61,7 +61,7 @@ SEC("kprobe/try_to_wake_up")
 int waker(struct pt_regs *ctx)
 {
        struct task_struct *p = (void *) PT_REGS_PARM1(ctx);
-       struct wokeby_t woke = {};
+       struct wokeby_t woke;
        u32 pid;
 
        pid = _(p->pid);
@@ -75,17 +75,19 @@ int waker(struct pt_regs *ctx)
 
 static inline int update_counts(void *ctx, u32 pid, u64 delta)
 {
-       struct key_t key = {};
        struct wokeby_t *woke;
        u64 zero = 0, *val;
+       struct key_t key;
 
+       __builtin_memset(&key.waker, 0, sizeof(key.waker));
        bpf_get_current_comm(&key.target, sizeof(key.target));
        key.tret = bpf_get_stackid(ctx, &stackmap, STACKID_FLAGS);
+       key.wret = 0;
 
        woke = bpf_map_lookup_elem(&wokeby, &pid);
        if (woke) {
                key.wret = woke->ret;
-               __builtin_memcpy(&key.waker, woke->name, TASK_COMM_LEN);
+               __builtin_memcpy(&key.waker, woke->name, sizeof(key.waker));
                bpf_map_delete_elem(&wokeby, &pid);
        }