From: Matthew Wilcox <mawilcox@microsoft.com>
Date: Fri, 8 Jun 2018 00:08:57 +0000 (-0700)
Subject: mm: add pt_mm to struct page
X-Git-Tag: v4.18-rc1~97^2~47
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=a052f0a5168ef99c517f6638aaec59f39060f81d;p=users%2Fjedix%2Flinux-maple.git

mm: add pt_mm to struct page

For pgd page table pages, x86 overloads the page->index field to store a
pointer to the mm_struct.  Rename this to pt_mm so it's visible to other
users.

Link: http://lkml.kernel.org/r/20180518194519.3820-13-willy@infradead.org
Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index ffc8c13c50e4..938dbcd46b97 100644
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -114,13 +114,12 @@ static inline void pgd_list_del(pgd_t *pgd)
 
 static void pgd_set_mm(pgd_t *pgd, struct mm_struct *mm)
 {
-	BUILD_BUG_ON(sizeof(virt_to_page(pgd)->index) < sizeof(mm));
-	virt_to_page(pgd)->index = (pgoff_t)mm;
+	virt_to_page(pgd)->pt_mm = mm;
 }
 
 struct mm_struct *pgd_page_get_mm(struct page *page)
 {
-	return (struct mm_struct *)page->index;
+	return page->pt_mm;
 }
 
 static void pgd_ctor(struct mm_struct *mm, pgd_t *pgd)
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 9b45760cc797..811aa0c71e1a 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -139,7 +139,7 @@ struct page {
 			unsigned long _pt_pad_1;	/* compound_head */
 			pgtable_t pmd_huge_pte; /* protected by page->ptl */
 			unsigned long _pt_pad_2;	/* mapping */
-			unsigned long _pt_pad_3;
+			struct mm_struct *pt_mm;	/* x86 pgds only */
 #if ALLOC_SPLIT_PTLOCKS
 			spinlock_t *ptl;
 #else