nilfs2: return the mapped address from nilfs_get_page()

stable inclusion
from stable-v4.19.319
commit 7ed62ec616a3441aa3859150d50fadf5fd117aa8
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAGEKP
CVE: CVE-2024-41034

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=7ed62ec616a3441aa3859150d50fadf5fd117aa8

--------------------------------

[ Upstream commit 09a46acb3697e50548bb265afa1d79163659dd85 ]

In prepartion for switching from kmap() to kmap_local(), return the kmap
address from nilfs_get_page() instead of having the caller look up
page_address().

[konishi.ryusuke: fixed a missing blank line after declaration]
Link: https://lkml.kernel.org/r/20231127143036.2425-7-konishi.ryusuke@gmail.com


Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Stable-dep-of: 7373a51e7998 ("nilfs2: fix nilfs_empty_dir() misjudgment and long loop on I/O errors")
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Zhihao Cheng <chengzhihao@huaweicloud.com>