On Wed, Jan 20, 2021 at 12:25:25PM +0200, Nikolay Borisov wrote:

Those constants are really used internally by zstd and including
linux/zstd.h into users results in the following warnings:

In file included from fs/btrfs/zstd.c:19:
./include/linux/zstd.h:798:21: warning: ‘ZSTD_skippableHeaderSize’ defined but not used [-Wunused-const-variable=]
  798 | static const size_t ZSTD_skippableHeaderSize = 8;
      |                     ^~~~~~~~~~~~~~~~~~~~~~~~
./include/linux/zstd.h:796:21: warning: ‘ZSTD_frameHeaderSize_max’ defined but not used [-Wunused-const-variable=]
  796 | static const size_t ZSTD_frameHeaderSize_max = ZSTD_FRAMEHEADERSIZE_MAX;
      |                     ^~~~~~~~~~~~~~~~~~~~~~~~
./include/linux/zstd.h:795:21: warning: ‘ZSTD_frameHeaderSize_min’ defined but not used [-Wunused-const-variable=]
  795 | static const size_t ZSTD_frameHeaderSize_min = ZSTD_FRAMEHEADERSIZE_MIN;
      |                     ^~~~~~~~~~~~~~~~~~~~~~~~
./include/linux/zstd.h:794:21: warning: ‘ZSTD_frameHeaderSize_prefix’ defined but not used [-Wunused-const-variable=]
  794 | static const size_t ZSTD_frameHeaderSize_prefix = 5;

So fix those warnings by turning the constants into defines.

Signed-off-by: Nikolay Borisov <redacted>
---
 include/linux/zstd.h | 8 ++++----

That's not our file and you haven't CCed the maintainer, we can't modify
that code without an ack.