[PATCH v4 3/5] mm/hugetlb: add hugetlb_folio_subpool() helpers

From: Sidhartha Kumar
Date: Thu Sep 22 2022 - 11:43:25 EST


Allows hugetlbfs_migrate_folio to check and read subpool information by
passing in a folio.

Signed-off-by: Sidhartha Kumar <sidhartha.kumar@xxxxxxxxxx>
Reviewed-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
---
fs/hugetlbfs/inode.c | 8 ++++----
include/linux/hugetlb.h | 15 +++++++++++++--
2 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index ed57a029eab0..5a4b136c6c36 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -1099,10 +1099,10 @@ static int hugetlbfs_migrate_folio(struct address_space *mapping,
if (rc != MIGRATEPAGE_SUCCESS)
return rc;

- if (hugetlb_page_subpool(&src->page)) {
- hugetlb_set_page_subpool(&dst->page,
- hugetlb_page_subpool(&src->page));
- hugetlb_set_page_subpool(&src->page, NULL);
+ if (hugetlb_folio_subpool(src)) {
+ hugetlb_set_folio_subpool(dst,
+ hugetlb_folio_subpool(src));
+ hugetlb_set_folio_subpool(src, NULL);
}

if (mode != MIGRATE_SYNC_NO_COPY)
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 8edcdb6a833f..f92b9e6c8f9e 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -752,18 +752,29 @@ extern unsigned int default_hstate_idx;

#define default_hstate (hstates[default_hstate_idx])

+static inline struct hugepage_subpool *hugetlb_folio_subpool(struct folio *folio)
+{
+ return (void *)folio_get_private_1(folio);
+}
+
/*
* hugetlb page subpool pointer located in hpage[1].private
*/
static inline struct hugepage_subpool *hugetlb_page_subpool(struct page *hpage)
{
- return (void *)page_private(hpage + SUBPAGE_INDEX_SUBPOOL);
+ return hugetlb_folio_subpool(page_folio(hpage));
+}
+
+static inline void hugetlb_set_folio_subpool(struct folio *folio,
+ struct hugepage_subpool *subpool)
+{
+ folio_set_private_1(folio, (unsigned long)subpool);
}

static inline void hugetlb_set_page_subpool(struct page *hpage,
struct hugepage_subpool *subpool)
{
- set_page_private(hpage + SUBPAGE_INDEX_SUBPOOL, (unsigned long)subpool);
+ hugetlb_set_folio_subpool(page_folio(hpage), subpool);
}

static inline struct hstate *hstate_file(struct file *f)
--
2.31.1