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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "Matthew Wilcox (Oracle)" <willy@infradead.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        William Kucharski <william.kucharski@oracle.com>,
        Zi Yan <ziy@nvidia.com>, David Hildenbrand <david@redhat.com>,
        Mike Kravetz <mike.kravetz@oracle.com>,
        "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
        Linus Torvalds <torvalds@linux-foundation.org>
Subject: [PATCH 5.4 65/78] mm: add thp_order
Date:   Tue,  8 Jun 2021 20:27:34 +0200
Message-Id: <20210608175937.462236794@linuxfoundation.org>
In-Reply-To: <20210608175935.254388043@linuxfoundation.org>
References: <20210608175935.254388043@linuxfoundation.org>
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From: "Matthew Wilcox (Oracle)" <willy@infradead.org>

commit 6ffbb45826f5d9ae09aa60cd88594b7816c96190 upstream

This function returns the order of a transparent huge page.  It compiles
to 0 if CONFIG_TRANSPARENT_HUGEPAGE is disabled.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Link: http://lkml.kernel.org/r/20200629151959.15779-4-willy@infradead.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 include/linux/huge_mm.h |   19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -231,6 +231,19 @@ static inline spinlock_t *pud_trans_huge
 	else
 		return NULL;
 }
+
+/**
+ * thp_order - Order of a transparent huge page.
+ * @page: Head page of a transparent huge page.
+ */
+static inline unsigned int thp_order(struct page *page)
+{
+	VM_BUG_ON_PGFLAGS(PageTail(page), page);
+	if (PageHead(page))
+		return HPAGE_PMD_ORDER;
+	return 0;
+}
+
 static inline int hpage_nr_pages(struct page *page)
 {
 	if (unlikely(PageTransHuge(page)))
@@ -290,6 +303,12 @@ static inline struct list_head *page_def
 #define HPAGE_PUD_MASK ({ BUILD_BUG(); 0; })
 #define HPAGE_PUD_SIZE ({ BUILD_BUG(); 0; })
 
+static inline unsigned int thp_order(struct page *page)
+{
+	VM_BUG_ON_PGFLAGS(PageTail(page), page);
+	return 0;
+}
+
 #define hpage_nr_pages(x) 1
 
 static inline bool __transparent_hugepage_enabled(struct vm_area_struct *vma)