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Commit 423bad60 authored by Nick Piggin's avatar Nick Piggin Committed by Linus Torvalds
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mm: add vm_insert_mixed 



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: default avatarNick 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 7e675137

include/linux/mm.h

+2 −0
Original line number Diff line number Diff line
@@ -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);

mm/memory.c

+60 −26
Original line number Diff line number Diff line
@@ -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 @@ static int insert_page(struct mm_struct *mm, unsigned long addr, struct page *pa 
 *

 * 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
@@ -1263,11 +1294,6 @@ EXPORT_SYMBOL(vm_insert_page); 
int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr,

			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
@@ -1280,27 +1306,35 @@ 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;

	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);



	/* 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);

int vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr,

			unsigned long pfn)

{

	BUG_ON(!(vma->vm_flags & VM_MIXEDMAP));



	retval = 0;

out_unlock:

	pte_unmap_unlock(pte, ptl);

	if (addr < vma->vm_start || addr >= vma->vm_end)

		return -EFAULT;



out:

	return retval;

	/*

	 * 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);

	}

EXPORT_SYMBOL(vm_insert_pfn);

	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