Re: [RFC PATCH 07/10] scsi/trace: Use scsi_show_result trace point instead of printk

Christoph Hellwig
2014-08-29T00:50:39Z

> I'm not sure this is the correct way.
> Currently we have quite some code duplication in scsi_trace.c and
> constants.c, correct.
> So I definitely would like to see them both merged.
>
> But constants.c is influenced by CONFIG_SCSI_CONSTANTS, whereas
> scsi_trace isn't, and the functions in constants.c are used throughout the
> scsi stack.
> So I'd rather see to have scsi_trace to be updated to use the functions
> from constants.c, and remove the duplicate code in
> scsi_trace.

The tracepoints need to use the magic print_flags & co helpers so that
output works properly if using the binary tracebuffer and user space tools that
decoded it (e.g. trace-cmd or perf), so using a kernel function for decoding is
not an option.

But we can make these tracepoints dependent on CONFIG_SCSI_CONSTANTS to
still allow building lighter kernels if we really care about it.