md: use folio APIs in free_page()

Convert the page to a folio.  This removes some of the last uses of a few
page APIs (detach_page_private(), page_buffers()).  Replaces two calls to
compound_head() with one.

Remove the early return in free_buffers() to avoid memory leak and
uninitialized file bitmap pages.[1][2]

[ziy@nvidia.com: drop early return]
Link: https://lore.kernel.org/20260920-remove-pg_private-v5-14-bb68b6a21869@nvidia.com
Link: https://sashiko.dev/#/patchset/20260913-remove-pg_private-v4-0-848550f7574e%40nvidia.com?part=2 [1]
Link: https://lore.kernel.org/all/aqgfA0QFi98gXYG2@casper.infradead.org/ [2]
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: David Hildenbrand (Arm) <david@kernel.org>

0 files changed, 0 insertions, 0 deletions