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Commit 0dc952dc authored by Christoph Lameter's avatar Christoph Lameter Committed by Linus Torvalds
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[PATCH] Page migration: Fix vma flag checking 



Currently we do not check for vma flags if sys_move_pages is called to move
individual pages.  If sys_migrate_pages is called to move pages then we
check for vm_flags that indicate a non migratable vma but that still
includes VM_LOCKED and we can migrate mlocked pages.

Extract the vma_migratable check from mm/mempolicy.c, fix it and put it
into migrate.h so that is can be used from both locations.

Problem was spotted by Lee Schermerhorn

Signed-off-by: default avatarChristoph Lameter <clameter@sgi.com>
Signed-off-by: default avatarLee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 1f2b69f9

include/linux/migrate.h

+8 −0
Original line number Original line Diff line number Diff line
@@ -5,6 +5,14 @@ 




typedef struct page *new_page_t(struct page *, unsigned long private, int **);

typedef struct page *new_page_t(struct page *, unsigned long private, int **);





/* Check if a vma is migratable */

static inline int vma_migratable(struct vm_area_struct *vma)

{

	if (vma->vm_flags & (VM_IO|VM_HUGETLB|VM_PFNMAP|VM_RESERVED))

		return 0;

	return 1;

}



#ifdef CONFIG_MIGRATION

#ifdef CONFIG_MIGRATION

extern int isolate_lru_page(struct page *p, struct list_head *pagelist);

extern int isolate_lru_page(struct page *p, struct list_head *pagelist);

extern int putback_lru_pages(struct list_head *l);

extern int putback_lru_pages(struct list_head *l);

mm/mempolicy.c

+0 −9
Original line number Original line Diff line number Diff line
@@ -321,15 +321,6 @@ static inline int check_pgd_range(struct vm_area_struct *vma, 
	return 0;

	return 0;

}

}





/* Check if a vma is migratable */

static inline int vma_migratable(struct vm_area_struct *vma)

{

	if (vma->vm_flags & (

		VM_LOCKED|VM_IO|VM_HUGETLB|VM_PFNMAP|VM_RESERVED))

		return 0;

	return 1;

}



/*

/*

 * Check if all pages in a range are on a set of nodes.

 * Check if all pages in a range are on a set of nodes.

 * If pagelist != NULL then isolate pages from the LRU and

 * If pagelist != NULL then isolate pages from the LRU and

mm/migrate.c

+1 −1
Original line number Original line Diff line number Diff line
@@ -781,7 +781,7 @@ static int do_move_pages(struct mm_struct *mm, struct page_to_node *pm, 




		err = -EFAULT;

		err = -EFAULT;

		vma = find_vma(mm, pp->addr);

		vma = find_vma(mm, pp->addr);

		if (!vma)

		if (!vma || !vma_migratable(vma))

			goto set_status;

			goto set_status;





		page = follow_page(vma, pp->addr, FOLL_GET);

		page = follow_page(vma, pp->addr, FOLL_GET);