On 3/26/18 11:11 AM, Steven Rostedt wrote:

On Mon, 26 Mar 2018 10:55:51 -0700
Alexei Starovoitov [off-list ref] wrote:

quoted

An email ago you were ok to s/return/return NULL/ in your out-of-tree
module, but now flip flop to add new function approach just to
reduce the work you need to do in lttng?
We're not talking about changing __kmalloc signature here.
My patch extends for_each_kernel_tracepoint() api similar to other
for_each_*() iterators and improves possible uses of it.

Alexei, do you have another use case for using
for_each_kernel_tracepoint() other than the find_tp? If so, then I'm
sure Mathieu can handle the change.

But I think it's cleaner to add a tracepoint_find_by_name() function.
If you come up with another use case for using the for_each* function
then we'll consider changing it then.

another use case ?! Frankly such reasoning smells.

I'm fine doing quick followup patch to add tracepoint_find_by_name()
and restore 'return void' behavior of for_each_kernel_tracepoint's
callback, but I'm struggling to accept the precedent it will create
that all exported functions of kernel/tracepoint.c are really
lttng extensions and we cannot easily change them.
I'd like to hear Linus take on this.