The BPF helper bpf_trace_printk() no longer uses trace_printk();
it is now triggers a dedicated trace event. Hence the described
warning is no longer present, so remove the discussion of it as
it may confuse people.
Fixes: ac5a72ea5c89 ("bpf: Use dedicated bpf_trace_printk event instead of trace_printk()")
Signed-off-by: Alan Maguire <[email protected]>
---
Documentation/bpf/bpf_design_QA.rst | 11 -----------
1 file changed, 11 deletions(-)
diff --git a/Documentation/bpf/bpf_design_QA.rst b/Documentation/bpf/bpf_design_QA.rst
index 12a246f..2df7b06 100644
--- a/Documentation/bpf/bpf_design_QA.rst
+++ b/Documentation/bpf/bpf_design_QA.rst
@@ -246,17 +246,6 @@ program is loaded the kernel will print warning message, so
this helper is only useful for experiments and prototypes.
Tracing BPF programs are root only.
-Q: bpf_trace_printk() helper warning
-------------------------------------
-Q: When bpf_trace_printk() helper is used the kernel prints nasty
-warning message. Why is that?
-
-A: This is done to nudge program authors into better interfaces when
-programs need to pass data to user space. Like bpf_perf_event_output()
-can be used to efficiently stream data via perf ring buffer.
-BPF maps can be used for asynchronous data sharing between kernel
-and user space. bpf_trace_printk() should only be used for debugging.
-
Q: New functionality via kernel modules?
----------------------------------------
Q: Can BPF functionality such as new program or map types, new
--
1.8.3.1
On 8/7/20 1:50 PM, Alan Maguire wrote:
> The BPF helper bpf_trace_printk() no longer uses trace_printk();
> it is now triggers a dedicated trace event. Hence the described
> warning is no longer present, so remove the discussion of it as
> it may confuse people.
>
> Fixes: ac5a72ea5c89 ("bpf: Use dedicated bpf_trace_printk event instead of trace_printk()")
> Signed-off-by: Alan Maguire <[email protected]>
Applied, thanks!