Quoting Brendan Higgins (2019-08-13 22:50:53)

A number of test features need to do pretty complicated string printing
where it may not be possible to rely on a single preallocated string
with parameters.

So provide a library for constructing the string as you go similar to
C++'s std::string. string_stream is really just a string builder,
nothing more.

Signed-off-by: Brendan Higgins <redacted>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
---

Reviewed-by: Stephen Boyd <redacted>

The spinlocks will probably need to change to be irqsaves in the future,
but I guess we can cross that bridge when we come to it.