From: "Darrick J. Wong" <redacted>
Date: Fri, 2 Jun 2017 11:08:08 -0700

ext4/jbd2's crc32c implementations will also need a fix like this for
{ext4,jbd2}_chksum.  Note that both of these modules call the crypto api
directly to avoid a static dependence on libcrc32c; this was done to
reduce kernel footprint for applications that don't need it.  (ext2,
ext3, and ext4 before the metadata_csum feature existed).

Good catch.  I even looked at that code the other day so should
have spotted it as well.

I'll integrate fixes for those into my patch when I get a chance,
thanks!