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Commit fb09a464 authored by Kirill A. Shutemov's avatar Kirill A. Shutemov Committed by Linus Torvalds
Browse files

mm: consolidate code to call vm_ops->page_mkwrite() 



There are two functions which need to call vm_ops->page_mkwrite():
do_shared_fault() and do_wp_page().  We can consolidate preparation
code.

Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Matthew Wilcox <matthew.r.wilcox@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent f0c6d4d2

mm/memory.c

+45 −60
Original line number Diff line number Diff line
@@ -2586,6 +2586,38 @@ static inline void cow_user_page(struct page *dst, struct page *src, unsigned lo 
		copy_user_highpage(dst, src, va, vma);

}



/*

 * Notify the address space that the page is about to become writable so that

 * it can prohibit this or wait for the page to get into an appropriate state.

 *

 * We do this without the lock held, so that it can sleep if it needs to.

 */

static int do_page_mkwrite(struct vm_area_struct *vma, struct page *page,

	       unsigned long address)

{

	struct vm_fault vmf;

	int ret;



	vmf.virtual_address = (void __user *)(address & PAGE_MASK);

	vmf.pgoff = page->index;

	vmf.flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE;

	vmf.page = page;



	ret = vma->vm_ops->page_mkwrite(vma, &vmf);

	if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))

		return ret;

	if (unlikely(!(ret & VM_FAULT_LOCKED))) {

		lock_page(page);

		if (!page->mapping) {

			unlock_page(page);

			return 0; /* retry */

		}

		ret |= VM_FAULT_LOCKED;

	} else

		VM_BUG_ON_PAGE(!PageLocked(page), page);

	return ret;

}



/*

 * This routine handles present pages, when users try to write

 * to a shared page. It is done by copying the page to a new address
@@ -2668,42 +2700,15 @@ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma, 
		 * get_user_pages(.write=1, .force=1).

		 */

		if (vma->vm_ops && vma->vm_ops->page_mkwrite) {

			struct vm_fault vmf;

			int tmp;



			vmf.virtual_address = (void __user *)(address &

								PAGE_MASK);

			vmf.pgoff = old_page->index;

			vmf.flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE;

			vmf.page = old_page;



			/*

			 * Notify the address space that the page is about to

			 * become writable so that it can prohibit this or wait

			 * for the page to get into an appropriate state.

			 *

			 * We do this without the lock held, so that it can

			 * sleep if it needs to.

			 */

			page_cache_get(old_page);

			pte_unmap_unlock(page_table, ptl);



			tmp = vma->vm_ops->page_mkwrite(vma, &vmf);

			if (unlikely(tmp &

					(VM_FAULT_ERROR | VM_FAULT_NOPAGE))) {

				ret = tmp;

				goto unwritable_page;

			}

			if (unlikely(!(tmp & VM_FAULT_LOCKED))) {

				lock_page(old_page);

				if (!old_page->mapping) {

					ret = 0; /* retry the fault */

					unlock_page(old_page);

					goto unwritable_page;

			tmp = do_page_mkwrite(vma, old_page, address);

			if (unlikely(!tmp || (tmp &

					(VM_FAULT_ERROR | VM_FAULT_NOPAGE)))) {

				page_cache_release(old_page);

				return tmp;

			}

			} else

				VM_BUG_ON_PAGE(!PageLocked(old_page), old_page);



			/*

			 * Since we dropped the lock we need to revalidate

			 * the PTE as someone else may have changed it.  If
@@ -2892,10 +2897,6 @@ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma, 
	if (old_page)

		page_cache_release(old_page);

	return VM_FAULT_OOM;



unwritable_page:

	page_cache_release(old_page);

	return ret;

}



static void unmap_mapping_range_vma(struct vm_area_struct *vma,
@@ -3419,7 +3420,6 @@ static int do_shared_fault(struct mm_struct *mm, struct vm_area_struct *vma, 
	spinlock_t *ptl;

	pte_t entry, *pte;

	int dirtied = 0;

	struct vm_fault vmf;

	int ret, tmp;



	ret = __do_fault(vma, address, pgoff, flags, &fault_page);
@@ -3430,31 +3430,16 @@ static int do_shared_fault(struct mm_struct *mm, struct vm_area_struct *vma, 
	 * Check if the backing address space wants to know that the page is

	 * about to become writable

	 */

	if (!vma->vm_ops->page_mkwrite)

		goto set_pte;



	if (vma->vm_ops->page_mkwrite) {

		unlock_page(fault_page);

	vmf.virtual_address = (void __user *)(address & PAGE_MASK);

	vmf.pgoff = pgoff;

	vmf.flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE;

	vmf.page = fault_page;



	tmp = vma->vm_ops->page_mkwrite(vma, &vmf);

	if (unlikely(tmp & (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) {

		tmp = do_page_mkwrite(vma, fault_page, address);

		if (unlikely(!tmp ||

				(tmp & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))) {

			page_cache_release(fault_page);

			return tmp;

		}



	if (unlikely(!(tmp & VM_FAULT_LOCKED))) {

		lock_page(fault_page);

		if (!fault_page->mapping) {

			unlock_page(fault_page);

			page_cache_release(fault_page);

			return 0; /* retry */

	}

	} else

		VM_BUG_ON_PAGE(!PageLocked(fault_page), fault_page);

set_pte:



	pte = pte_offset_map_lock(mm, pmd, address, &ptl);

	if (unlikely(!pte_same(*pte, orig_pte))) {

		pte_unmap_unlock(pte, ptl);