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mm: add vm_insert_mixed

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vm_insert_mixed will insert either a raw pfn or a refcounted struct page into
the page tables, depending on whether vm_normal_page() will return the page or
not.  With the introduction of the new pte bit, this is now a too tricky for
drivers to be doing themselves.

filemap_xip uses this in a subsequent patch.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Jared Hulbert <jaredeh@gmail.com>
Cc: Carsten Otte <cotte@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Nick Piggin 2008-04-28 02:13:01 -07:00 committed by Linus Torvalds
parent 7e675137a8
commit 423bad6004
2 changed files with 64 additions and 28 deletions
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2
include/linux/mm.h
View File

@ -1152,6 +1152,8 @@ int remap_pfn_range(struct vm_area_struct *, unsigned long addr,
int vm_insert_page(struct vm_area_struct *, unsigned long addr, struct page *);
int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr,
unsigned long pfn);
int vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr,
unsigned long pfn);
struct page *follow_page(struct vm_area_struct *, unsigned long address,
unsigned int foll_flags);

90
mm/memory.c
View File

@ -1176,8 +1176,10 @@ pte_t *get_locked_pte(struct mm_struct *mm, unsigned long addr,
* old drivers should use this, and they needed to mark their
* pages reserved for the old functions anyway.
*/
static int insert_page(struct mm_struct *mm, unsigned long addr, struct page *page, pgprot_t prot)
static int insert_page(struct vm_area_struct *vma, unsigned long addr,
struct page *page, pgprot_t prot)
{
struct mm_struct *mm = vma->vm_mm;
int retval;
pte_t *pte;
spinlock_t *ptl;
@ -1237,17 +1239,46 @@ out:
*
* The page does not need to be reserved.
*/
int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, struct page *page)
int vm_insert_page(struct vm_area_struct *vma, unsigned long addr,
struct page *page)
{
if (addr < vma->vm_start || addr >= vma->vm_end)
return -EFAULT;
if (!page_count(page))
return -EINVAL;
vma->vm_flags |= VM_INSERTPAGE;
return insert_page(vma->vm_mm, addr, page, vma->vm_page_prot);
return insert_page(vma, addr, page, vma->vm_page_prot);
}
EXPORT_SYMBOL(vm_insert_page);
static int insert_pfn(struct vm_area_struct *vma, unsigned long addr,
unsigned long pfn, pgprot_t prot)
{
struct mm_struct *mm = vma->vm_mm;
int retval;
pte_t *pte, entry;
spinlock_t *ptl;
retval = -ENOMEM;
pte = get_locked_pte(mm, addr, &ptl);
if (!pte)
goto out;
retval = -EBUSY;
if (!pte_none(*pte))
goto out_unlock;
/* Ok, finally just insert the thing.. */
entry = pte_mkspecial(pfn_pte(pfn, prot));
set_pte_at(mm, addr, pte, entry);
update_mmu_cache(vma, addr, entry); /* XXX: why not for insert_page? */
retval = 0;
out_unlock:
pte_unmap_unlock(pte, ptl);
out:
return retval;
}
/**
* vm_insert_pfn - insert single pfn into user vma
* @vma: user vma to map to
@ -1261,13 +1292,8 @@ EXPORT_SYMBOL(vm_insert_page);
* in that case the handler should return NULL.
*/
int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr,
unsigned long pfn)
unsigned long pfn)
{
struct mm_struct *mm = vma->vm_mm;
int retval;
pte_t *pte, entry;
spinlock_t *ptl;
/*
* Technically, architectures with pte_special can avoid all these
* restrictions (same for remap_pfn_range). However we would like
@ -1280,28 +1306,36 @@ int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr,
BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags));
BUG_ON((vma->vm_flags & VM_MIXEDMAP) && pfn_valid(pfn));
retval = -ENOMEM;
pte = get_locked_pte(mm, addr, &ptl);
if (!pte)
goto out;
retval = -EBUSY;
if (!pte_none(*pte))
goto out_unlock;
/* Ok, finally just insert the thing.. */
entry = pte_mkspecial(pfn_pte(pfn, vma->vm_page_prot));
set_pte_at(mm, addr, pte, entry);
update_mmu_cache(vma, addr, entry);
retval = 0;
out_unlock:
pte_unmap_unlock(pte, ptl);
out:
return retval;
if (addr < vma->vm_start || addr >= vma->vm_end)
return -EFAULT;
return insert_pfn(vma, addr, pfn, vma->vm_page_prot);
}
EXPORT_SYMBOL(vm_insert_pfn);
int vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr,
unsigned long pfn)
{
BUG_ON(!(vma->vm_flags & VM_MIXEDMAP));
if (addr < vma->vm_start || addr >= vma->vm_end)
return -EFAULT;
/*
* If we don't have pte special, then we have to use the pfn_valid()
* based VM_MIXEDMAP scheme (see vm_normal_page), and thus we *must*
* refcount the page if pfn_valid is true (hence insert_page rather
* than insert_pfn).
*/
if (!HAVE_PTE_SPECIAL && pfn_valid(pfn)) {
struct page *page;
page = pfn_to_page(pfn);
return insert_page(vma, addr, page, vma->vm_page_prot);
}
return insert_pfn(vma, addr, pfn, vma->vm_page_prot);
}
EXPORT_SYMBOL(vm_insert_mixed);
/*
* maps a range of physical memory into the requested pages. the old
* mappings are removed. any references to nonexistent pages results