From 7fb20f9e901e6df2f7dc032d88da5abff4117d37 Mon Sep 17 00:00:00 2001 From: Alan Maguire Date: Fri, 7 Aug 2020 12:50:29 +0100 Subject: bpf, doc: Remove references to warning message when using bpf_trace_printk() 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 Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/1596801029-32395-1-git-send-email-alan.maguire@oracle.com --- Documentation/bpf/bpf_design_QA.rst | 11 ----------- 1 file changed, 11 deletions(-) (limited to 'Documentation') diff --git a/Documentation/bpf/bpf_design_QA.rst b/Documentation/bpf/bpf_design_QA.rst index 12a246fcf6cb..2df7b067ab93 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 -- cgit v1.2.3