tree dc5478189be0f6a321bfc23ee0545f71de67763b
parent 199c36eaa95077a47ae1bc55532fc0fbeb80cc95
author Chris Mason <chris.mason@oracle.com> 1311091454 -0400
committer Chris Mason <chris.mason@oracle.com> 1311785205 -0400

Btrfs: stop using highmem for extent_buffers

The extent_buffers have a very complex interface where
we use HIGHMEM for metadata and try to cache a kmap mapping
to access the memory.

The next commit adds reader/writer locks, and concurrent use
of this kmap cache would make it even more complex.

This commit drops the ability to use HIGHMEM with extent buffers,
and rips out all of the related code.

Signed-off-by: Chris Mason <chris.mason@oracle.com>