linux-kernel - [PATCH v5 4/5] mm: Use is_cow_mapping() across tree where proper

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Date:   Wed, 17 Feb 2021 18:35:46 -0500
From:   Peter Xu <peterx@...hat.com>
To:     linux-mm@...ck.org, linux-kernel@...r.kernel.org
Cc:     Gal Pressman <galpress@...zon.com>,
        Matthew Wilcox <willy@...radead.org>,
        Wei Zhang <wzam@...zon.com>, peterx@...hat.com,
        Mike Kravetz <mike.kravetz@...cle.com>,
        Mike Rapoport <rppt@...ux.vnet.ibm.com>,
        Christoph Hellwig <hch@....de>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        David Gibson <david@...son.dropbear.id.au>,
        Jason Gunthorpe <jgg@...pe.ca>, Jann Horn <jannh@...gle.com>,
        Kirill Tkhai <ktkhai@...tuozzo.com>,
        Kirill Shutemov <kirill@...temov.name>,
        Miaohe Lin <linmiaohe@...wei.com>,
        Andrea Arcangeli <aarcange@...hat.com>,
        Jan Kara <jack@...e.cz>,
        VMware Graphics <linux-graphics-maintainer@...are.com>,
        Roland Scheidegger <sroland@...are.com>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Alexey Dobriyan <adobriyan@...il.com>
Subject: [PATCH v5 4/5] mm: Use is_cow_mapping() across tree where proper

After is_cow_mapping() is exported in mm.h, replace some manual checks
elsewhere throughout the tree but start to use the new helper.

Cc: VMware Graphics <linux-graphics-maintainer@...are.com>
Cc: Roland Scheidegger <sroland@...are.com>
Cc: David Airlie <airlied@...ux.ie>
Cc: Daniel Vetter <daniel@...ll.ch>
Cc: Mike Kravetz <mike.kravetz@...cle.com>
Cc: Alexey Dobriyan <adobriyan@...il.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Reviewed-by: Jason Gunthorpe <jgg@...pe.ca>
Signed-off-by: Peter Xu <peterx@...hat.com>
---
 drivers/gpu/drm/vmwgfx/vmwgfx_page_dirty.c | 4 +---
 drivers/gpu/drm/vmwgfx/vmwgfx_ttm_glue.c   | 2 +-
 fs/proc/task_mmu.c                         | 2 --
 mm/hugetlb.c                               | 4 +---
 4 files changed, 3 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_page_dirty.c b/drivers/gpu/drm/vmwgfx/vmwgfx_page_dirty.c
index 0a900afc66ff..45c9c6a7f1d6 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_page_dirty.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_page_dirty.c
@@ -500,8 +500,6 @@ vm_fault_t vmw_bo_vm_huge_fault(struct vm_fault *vmf,
 	vm_fault_t ret;
 	pgoff_t fault_page_size;
 	bool write = vmf->flags & FAULT_FLAG_WRITE;
-	bool is_cow_mapping =
-		(vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
 
 	switch (pe_size) {
 	case PE_SIZE_PMD:
@@ -518,7 +516,7 @@ vm_fault_t vmw_bo_vm_huge_fault(struct vm_fault *vmf,
 	}
 
 	/* Always do write dirty-tracking and COW on PTE level. */
-	if (write && (READ_ONCE(vbo->dirty) || is_cow_mapping))
+	if (write && (READ_ONCE(vbo->dirty) || is_cow_mapping(vma->vm_flags)))
 		return VM_FAULT_FALLBACK;
 
 	ret = ttm_bo_vm_reserve(bo, vmf);
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_ttm_glue.c b/drivers/gpu/drm/vmwgfx/vmwgfx_ttm_glue.c
index 3c03b1746661..cb9975889e2f 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_ttm_glue.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_ttm_glue.c
@@ -49,7 +49,7 @@ int vmw_mmap(struct file *filp, struct vm_area_struct *vma)
 	vma->vm_ops = &vmw_vm_ops;
 
 	/* Use VM_PFNMAP rather than VM_MIXEDMAP if not a COW mapping */
-	if ((vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) != VM_MAYWRITE)
+	if (!is_cow_mapping(vma->vm_flags))
 		vma->vm_flags = (vma->vm_flags & ~VM_MIXEDMAP) | VM_PFNMAP;
 
 	return 0;
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 3cec6fbef725..e862cab69583 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -1036,8 +1036,6 @@ struct clear_refs_private {
 
 #ifdef CONFIG_MEM_SOFT_DIRTY
 
-#define is_cow_mapping(flags) (((flags) & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE)
-
 static inline bool pte_is_pinned(struct vm_area_struct *vma, unsigned long addr, pte_t pte)
 {
 	struct page *page;
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 2ba4ea4ab46e..8379224e1d43 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -3731,15 +3731,13 @@ int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
 	pte_t *src_pte, *dst_pte, entry, dst_entry;
 	struct page *ptepage;
 	unsigned long addr;
-	int cow;
+	bool cow = is_cow_mapping(vma->vm_flags);
 	struct hstate *h = hstate_vma(vma);
 	unsigned long sz = huge_page_size(h);
 	struct address_space *mapping = vma->vm_file->f_mapping;
 	struct mmu_notifier_range range;
 	int ret = 0;
 
-	cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
-
 	if (cow) {
 		mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, src,
 					vma->vm_start,
-- 
2.26.2