[PATCH v2 18/28] hugetlb: Use try_grab_folio() instead of try_grab_compound_head()

From: Matthew Wilcox (Oracle)
Date: Sun Jan 09 2022 - 23:25:02 EST


follow_hugetlb_page() only cares about success or failure, so it doesn't
need to know the type of the returned pointer, only whether it's NULL
or not.

Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
---
include/linux/mm.h | 3 ---
mm/gup.c | 2 +-
mm/hugetlb.c | 7 +++----
3 files changed, 4 insertions(+), 8 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index b249156f7cf1..c103c6401ecd 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1195,9 +1195,6 @@ static inline void get_page(struct page *page)
}

bool __must_check try_grab_page(struct page *page, unsigned int flags);
-struct page *try_grab_compound_head(struct page *page, int refs,
- unsigned int flags);
-

static inline __must_check bool try_get_page(struct page *page)
{
diff --git a/mm/gup.c b/mm/gup.c
index 719252fa0402..20703de2f107 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -146,7 +146,7 @@ struct folio *try_grab_folio(struct page *page, int refs, unsigned int flags)
return NULL;
}

-struct page *try_grab_compound_head(struct page *page,
+static inline struct page *try_grab_compound_head(struct page *page,
int refs, unsigned int flags)
{
return &try_grab_folio(page, refs, flags)->page;
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index abcd1785c629..ab67b13c4a71 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -6072,7 +6072,7 @@ long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,

if (pages) {
/*
- * try_grab_compound_head() should always succeed here,
+ * try_grab_folio() should always succeed here,
* because: a) we hold the ptl lock, and b) we've just
* checked that the huge page is present in the page
* tables. If the huge page is present, then the tail
@@ -6081,9 +6081,8 @@ long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
* any way. So this page must be available at this
* point, unless the page refcount overflowed:
*/
- if (WARN_ON_ONCE(!try_grab_compound_head(pages[i],
- refs,
- flags))) {
+ if (WARN_ON_ONCE(!try_grab_folio(pages[i], refs,
+ flags))) {
spin_unlock(ptl);
remainder = 0;
err = -ENOMEM;
--
2.33.0