nilfs2: eliminate staggered calls to kunmap in nilfs_rename
authorRyusuke Konishi <konishi.ryusuke@gmail.com>
Mon, 27 Nov 2023 14:30:21 +0000 (23:30 +0900)
committerAndrew Morton <akpm@linux-foundation.org>
Mon, 11 Dec 2023 01:21:45 +0000 (17:21 -0800)
commit8cf57c6df818f58fdad16a909506be213623a88e
treec6f9695d5af467e664b0c396f497dc2d16964cfd
parent584db20c181f5e28c0386d7987406ace7fbd3e49
nilfs2: eliminate staggered calls to kunmap in nilfs_rename

In nilfs_rename(), calls to nilfs_put_page() to release pages obtained
with nilfs_find_entry() or nilfs_dotdot() are alternated in the normal
path.

When replacing the kernel memory mapping method from kmap to
kmap_local_{page,folio}, this violates the constraint on the calling order
of kunmap_local().

Swap the order of nilfs_put_page calls where the kmap sections of multiple
pages overlap so that they are nested, allowing direct replacement of
nilfs_put_page() -> unmap_and_put_page().

Without this reordering, that replacement will cause a kernel WARNING in
kunmap_local_indexed() on architectures with high memory mapping.

Link: https://lkml.kernel.org/r/20231127143036.2425-3-konishi.ryusuke@gmail.com
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
fs/nilfs2/namei.c