The k[un]map() calls in ext2_[get|put]_page() are localized to a single
thread. kmap_local_page() is more efficient.
Replace the kmap/kunmap calls with kmap_local_page()/kunmap_local().
kunmap_local() requires the mapping address so return that address from
ext2_get_page() to be used in ext2_put_page(). This works well because
many of the callers need the address anyway so it is not bad to return
it along with the page.
In addition, kmap_local_page()/kunmap_local() require strict nesting
rules to be followed.
Document the new nesting requirements of ext2_get_page() and
ext2_put_page() as well as the relationship between ext2_get_page(),
ext2_find_entry(), and ext2_dotdot().
Adjust one ext2_put_page() call site in ext2_rename() to ensure the new
nesting requirements are met.
Finally, adjust code style for checkpatch.
To: Jan Kara <jack@suse.com>
Link: https://lore.kernel.org/r/20210329065402.3297092-3-ira.weiny@intel.com
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Jan Kara <jack@suse.cz>
782b76d7ab