[PATCH 8/9] huge tmpfs: decide stat.st_blksize by shmem_is_huge()

From: Hugh Dickins
Date: Tue Aug 17 2021 - 04:22:46 EST


4.18 commit 89fdcd262fd4 ("mm: shmem: make stat.st_blksize return huge
page size if THP is on") added is_huge_enabled() to decide st_blksize:
if hugeness is to be defined per file, that will need to be replaced by
shmem_is_huge().

This does give a different answer (No) for small files on a
"huge=within_size" mount: but that can be considered a minor bugfix.
And a different answer (No) for default files on a "huge=advise" mount:
I'm reluctant to complicate it, just to reproduce the same debatable
answer as before.

Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx>
Reviewed-by: Yang Shi <shy828301@xxxxxxxxx>
---
mm/shmem.c | 12 +-----------
1 file changed, 1 insertion(+), 11 deletions(-)

diff --git a/mm/shmem.c b/mm/shmem.c
index 56ee56b1cab6..b60a7abff27d 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -689,15 +689,6 @@ static unsigned long shmem_unused_huge_shrink(struct shmem_sb_info *sbinfo,
}
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */

-static inline bool is_huge_enabled(struct shmem_sb_info *sbinfo)
-{
- if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&
- (shmem_huge == SHMEM_HUGE_FORCE || sbinfo->huge) &&
- shmem_huge != SHMEM_HUGE_DENY)
- return true;
- return false;
-}
-
/*
* Like add_to_page_cache_locked, but error if expected item has gone.
*/
@@ -1078,7 +1069,6 @@ static int shmem_getattr(struct user_namespace *mnt_userns,
{
struct inode *inode = path->dentry->d_inode;
struct shmem_inode_info *info = SHMEM_I(inode);
- struct shmem_sb_info *sb_info = SHMEM_SB(inode->i_sb);

if (info->alloced - info->swapped != inode->i_mapping->nrpages) {
spin_lock_irq(&info->lock);
@@ -1087,7 +1077,7 @@ static int shmem_getattr(struct user_namespace *mnt_userns,
}
generic_fillattr(&init_user_ns, inode, stat);

- if (is_huge_enabled(sb_info))
+ if (shmem_is_huge(NULL, inode, 0))
stat->blksize = HPAGE_PMD_SIZE;

return 0;
--
2.26.2