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mm: add zap_vma_ptes(): a library function to unmap driver ptes

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zap_vma_ptes() is intended to be used by drivers to unmap ptes assigned to the
driver private vmas.  This interface is similar to zap_page_range() but is
less general & less likely to be abused.

Needed by the GRU driver.

Signed-off-by: Jack Steiner <steiner@sgi.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Jack Steiner 2008-07-29 22:33:53 -07:00 committed by Linus Torvalds
parent f718cd4add
commit c627f9cc04
2 changed files with 25 additions and 0 deletions
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2
include/linux/mm.h
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@ -744,6 +744,8 @@ struct zap_details {
struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr, struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
pte_t pte); pte_t pte);
int zap_vma_ptes(struct vm_area_struct *vma, unsigned long address,
unsigned long size);
unsigned long zap_page_range(struct vm_area_struct *vma, unsigned long address, unsigned long zap_page_range(struct vm_area_struct *vma, unsigned long address,
unsigned long size, struct zap_details *); unsigned long size, struct zap_details *);
unsigned long unmap_vmas(struct mmu_gather **tlb, unsigned long unmap_vmas(struct mmu_gather **tlb,

23
mm/memory.c
View File

@ -994,6 +994,29 @@ unsigned long zap_page_range(struct vm_area_struct *vma, unsigned long address,
return end; return end;
} }
/**
* zap_vma_ptes - remove ptes mapping the vma
* @vma: vm_area_struct holding ptes to be zapped
* @address: starting address of pages to zap
* @size: number of bytes to zap
*
* This function only unmaps ptes assigned to VM_PFNMAP vmas.
*
* The entire address range must be fully contained within the vma.
*
* Returns 0 if successful.
*/
int zap_vma_ptes(struct vm_area_struct *vma, unsigned long address,
unsigned long size)
{
if (address < vma->vm_start || address + size > vma->vm_end ||
!(vma->vm_flags & VM_PFNMAP))
return -1;
zap_page_range(vma, address, size, NULL);
return 0;
}
EXPORT_SYMBOL_GPL(zap_vma_ptes);
/* /*
* Do a quick page-table lookup for a single page. * Do a quick page-table lookup for a single page.
*/ */