[PATCH 6.1 18/71] erofs: apply proper VMA alignment for memory mapped files on THP

Sasha Levin
2024-03-13T16:40:21Z

From: Gao Xiang <hsiangkao@linux.alibaba.com>

[ Upstream commit 4127caee89612a84adedd78c9453089138cd5afe ]

There are mainly two reasons that thp_get_unmapped_area() should be
used for EROFS as other filesystems:

- It's needed to enable PMD mappings as a FSDAX filesystem, see
commit 74d2fad1334d ("thp, dax: add thp_get_unmapped_area for pmd
mappings");

- It's useful together with large folios and
CONFIG_READ_ONLY_THP_FOR_FS which enable THPs for mmapped files
(e.g. shared libraries) even without FSDAX. See commit 1854bc6e2420
("mm/readahead: Align file mappings for non-DAX").

Fixes: 06252e9ce05b ("erofs: dax support for non-tailpacking regular file")
Fixes: ce529cc25b18 ("erofs: enable large folios for iomap mode")
Fixes: e6687b89225e ("erofs: enable large folios for fscache mode")
Reviewed-by: Jingbo Xu <jefflexu@linux.alibaba.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Link: https://lore.kernel.org/r/20240306053138.2240206-1-hsiangkao@linux.alibaba.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/erofs/data.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/fs/erofs/data.c b/fs/erofs/data.c
index b32801d716f89..9d20e5d23ae0b 100644
--- a/fs/erofs/data.c
+++ b/fs/erofs/data.c
@@ -440,4 +440,5 @@ const struct file_operations erofs_file_fops = {
.read_iter = erofs_file_read_iter,
.mmap = erofs_file_mmap,
.splice_read = generic_file_splice_read,
+ .get_unmapped_area = thp_get_unmapped_area,
};
--
2.43.0