---

yaml
---
r: 69603
b: refs/heads/master
c: 557ed1f
h: refs/heads/master
i:
  69601: 2ba7be0
  69599: 868bb83
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: aadb4bc4a1f9108c1d0fbd121827c936c2ed4217
+refs/heads/master: 557ed1fa2620dc119adb86b34c614e152a629a80

trunk/drivers/char/mem.c

@@ -625,135 +625,44 @@ static ssize_t splice_write_null(struct pipe_inode_info *pipe,struct file *out,
 	return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_null);
 }
 
-#ifdef CONFIG_MMU
-/*
- * For fun, we are using the MMU for this.
- */
-static inline size_t read_zero_pagealigned(char __user * buf, size_t size)
-{
-	struct mm_struct *mm;
-	struct vm_area_struct * vma;
-	unsigned long addr=(unsigned long)buf;
-
-	mm = current->mm;
-	/* Oops, this was forgotten before. -ben */
-	down_read(&mm->mmap_sem);
-
-	/* For private mappings, just map in zero pages. */
-	for (vma = find_vma(mm, addr); vma; vma = vma->vm_next) {
-		unsigned long count;
-
-		if (vma->vm_start > addr || (vma->vm_flags & VM_WRITE) == 0)
-			goto out_up;
-		if (vma->vm_flags & (VM_SHARED | VM_HUGETLB))
-			break;
-		count = vma->vm_end - addr;
-		if (count > size)
-			count = size;
-
-		zap_page_range(vma, addr, count, NULL);
-        	if (zeromap_page_range(vma, addr, count, PAGE_COPY))
-			break;
-
-		size -= count;
-		buf += count;
-		addr += count;
-		if (size == 0)
-			goto out_up;
-	}
-
-	up_read(&mm->mmap_sem);
-
-	/* The shared case is hard. Let's do the conventional zeroing. */ 
-	do {
-		unsigned long unwritten = clear_user(buf, PAGE_SIZE);
-		if (unwritten)
-			return size + unwritten - PAGE_SIZE;
-		cond_resched();
-		buf += PAGE_SIZE;
-		size -= PAGE_SIZE;
-	} while (size);
-
-	return size;
-out_up:
-	up_read(&mm->mmap_sem);
-	return size;
-}
-
 static ssize_t read_zero(struct file * file, char __user * buf, 
 			 size_t count, loff_t *ppos)
 {
-	unsigned long left, unwritten, written = 0;
+	size_t written;
 
 	if (!count)
 		return 0;
 
 	if (!access_ok(VERIFY_WRITE, buf, count))
 		return -EFAULT;
 
-	left = count;
-
-	/* do we want to be clever? Arbitrary cut-off */
-	if (count >= PAGE_SIZE*4) {
-		unsigned long partial;
+	written = 0;
+	while (count) {
+		unsigned long unwritten;
+		size_t chunk = count;
 
-		/* How much left of the page? */
-		partial = (PAGE_SIZE-1) & -(unsigned long) buf;
-		unwritten = clear_user(buf, partial);
-		written = partial - unwritten;
-		if (unwritten)
-			goto out;
-		left -= partial;
-		buf += partial;
-		unwritten = read_zero_pagealigned(buf, left & PAGE_MASK);
-		written += (left & PAGE_MASK) - unwritten;
+		if (chunk > PAGE_SIZE)
+			chunk = PAGE_SIZE;	/* Just for latency reasons */
+		unwritten = clear_user(buf, chunk);
+		written += chunk - unwritten;
 		if (unwritten)
-			goto out;
-		buf += left & PAGE_MASK;
-		left &= ~PAGE_MASK;
-	}
-	unwritten = clear_user(buf, left);
-	written += left - unwritten;
-out:
-	return written ? written : -EFAULT;
-}
-
-static int mmap_zero(struct file * file, struct vm_area_struct * vma)
-{
-	int err;
-
-	if (vma->vm_flags & VM_SHARED)
-		return shmem_zero_setup(vma);
-	err = zeromap_page_range(vma, vma->vm_start,
-			vma->vm_end - vma->vm_start, vma->vm_page_prot);
-	BUG_ON(err == -EEXIST);
-	return err;
-}
-#else /* CONFIG_MMU */
-static ssize_t read_zero(struct file * file, char * buf, 
-			 size_t count, loff_t *ppos)
-{
-	size_t todo = count;
-
-	while (todo) {
-		size_t chunk = todo;
-
-		if (chunk > 4096)
-			chunk = 4096;	/* Just for latency reasons */
-		if (clear_user(buf, chunk))
-			return -EFAULT;
+			break;
 		buf += chunk;
-		todo -= chunk;
+		count -= chunk;
 		cond_resched();
 	}
-	return count;
+	return written ? written : -EFAULT;
 }
 
 static int mmap_zero(struct file * file, struct vm_area_struct * vma)
 {
+#ifndef CONFIG_MMU
 	return -ENOSYS;
+#endif
+	if (vma->vm_flags & VM_SHARED)
+		return shmem_zero_setup(vma);
+	return 0;
 }
-#endif /* CONFIG_MMU */
 
 static ssize_t write_full(struct file * file, const char __user * buf,
 			  size_t count, loff_t *ppos)

trunk/fs/binfmt_elf.c

@@ -1725,7 +1725,7 @@ static int elf_core_dump(long signr, struct pt_regs *regs, struct file *file)
 						&page, &vma) <= 0) {
 				DUMP_SEEK(PAGE_SIZE);
 			} else {
-				if (page == ZERO_PAGE(addr)) {
+				if (page == ZERO_PAGE(0)) {
 					if (!dump_seek(file, PAGE_SIZE)) {
 						page_cache_release(page);
 						goto end_coredump;

trunk/fs/binfmt_elf_fdpic.c

@@ -1488,7 +1488,7 @@ static int elf_fdpic_dump_segments(struct file *file, size_t *size,
 					   &page, &vma) <= 0) {
 				DUMP_SEEK(file->f_pos + PAGE_SIZE);
 			}
-			else if (page == ZERO_PAGE(addr)) {
+			else if (page == ZERO_PAGE(0)) {
 				page_cache_release(page);
 				DUMP_SEEK(file->f_pos + PAGE_SIZE);
 			}

trunk/fs/direct-io.c

@@ -163,7 +163,7 @@ static int dio_refill_pages(struct dio *dio)
 	up_read(&current->mm->mmap_sem);
 
 	if (ret < 0 && dio->blocks_available && (dio->rw & WRITE)) {
-		struct page *page = ZERO_PAGE(dio->curr_user_address);
+		struct page *page = ZERO_PAGE(0);
 		/*
 		 * A memory fault, but the filesystem has some outstanding
 		 * mapped blocks.  We need to use those blocks up to avoid
@@ -763,7 +763,7 @@ static void dio_zero_block(struct dio *dio, int end)
 
 	this_chunk_bytes = this_chunk_blocks << dio->blkbits;
 
-	page = ZERO_PAGE(dio->curr_user_address);
+	page = ZERO_PAGE(0);
 	if (submit_page_section(dio, page, 0, this_chunk_bytes, 
 				dio->next_block_for_io))
 		return;

trunk/include/linux/mm.h

@@ -779,8 +779,6 @@ void free_pgtables(struct mmu_gather **tlb, struct vm_area_struct *start_vma,
 		unsigned long floor, unsigned long ceiling);
 int copy_page_range(struct mm_struct *dst, struct mm_struct *src,
 			struct vm_area_struct *vma);
-int zeromap_page_range(struct vm_area_struct *vma, unsigned long from,
-			unsigned long size, pgprot_t prot);
 void unmap_mapping_range(struct address_space *mapping,
 		loff_t const holebegin, loff_t const holelen, int even_cows);
 

trunk/mm/memory.c

@@ -966,7 +966,7 @@ struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
 	 * has touched so far, we don't want to allocate page tables.
 	 */
 	if (flags & FOLL_ANON) {
-		page = ZERO_PAGE(address);
+		page = ZERO_PAGE(0);
 		if (flags & FOLL_GET)
 			get_page(page);
 		BUG_ON(flags & FOLL_WRITE);
@@ -1111,95 +1111,6 @@ int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
 }
 EXPORT_SYMBOL(get_user_pages);
 
-static int zeromap_pte_range(struct mm_struct *mm, pmd_t *pmd,
-			unsigned long addr, unsigned long end, pgprot_t prot)
-{
-	pte_t *pte;
-	spinlock_t *ptl;
-	int err = 0;
-
-	pte = pte_alloc_map_lock(mm, pmd, addr, &ptl);
-	if (!pte)
-		return -EAGAIN;
-	arch_enter_lazy_mmu_mode();
-	do {
-		struct page *page = ZERO_PAGE(addr);
-		pte_t zero_pte = pte_wrprotect(mk_pte(page, prot));
-
-		if (unlikely(!pte_none(*pte))) {
-			err = -EEXIST;
-			pte++;
-			break;
-		}
-		page_cache_get(page);
-		page_add_file_rmap(page);
-		inc_mm_counter(mm, file_rss);
-		set_pte_at(mm, addr, pte, zero_pte);
-	} while (pte++, addr += PAGE_SIZE, addr != end);
-	arch_leave_lazy_mmu_mode();
-	pte_unmap_unlock(pte - 1, ptl);
-	return err;
-}
-
-static inline int zeromap_pmd_range(struct mm_struct *mm, pud_t *pud,
-			unsigned long addr, unsigned long end, pgprot_t prot)
-{
-	pmd_t *pmd;
-	unsigned long next;
-	int err;
-
-	pmd = pmd_alloc(mm, pud, addr);
-	if (!pmd)
-		return -EAGAIN;
-	do {
-		next = pmd_addr_end(addr, end);
-		err = zeromap_pte_range(mm, pmd, addr, next, prot);
-		if (err)
-			break;
-	} while (pmd++, addr = next, addr != end);
-	return err;
-}
-
-static inline int zeromap_pud_range(struct mm_struct *mm, pgd_t *pgd,
-			unsigned long addr, unsigned long end, pgprot_t prot)
-{
-	pud_t *pud;
-	unsigned long next;
-	int err;
-
-	pud = pud_alloc(mm, pgd, addr);
-	if (!pud)
-		return -EAGAIN;
-	do {
-		next = pud_addr_end(addr, end);
-		err = zeromap_pmd_range(mm, pud, addr, next, prot);
-		if (err)
-			break;
-	} while (pud++, addr = next, addr != end);
-	return err;
-}
-
-int zeromap_page_range(struct vm_area_struct *vma,
-			unsigned long addr, unsigned long size, pgprot_t prot)
-{
-	pgd_t *pgd;
-	unsigned long next;
-	unsigned long end = addr + size;
-	struct mm_struct *mm = vma->vm_mm;
-	int err;
-
-	BUG_ON(addr >= end);
-	pgd = pgd_offset(mm, addr);
-	flush_cache_range(vma, addr, end);
-	do {
-		next = pgd_addr_end(addr, end);
-		err = zeromap_pud_range(mm, pgd, addr, next, prot);
-		if (err)
-			break;
-	} while (pgd++, addr = next, addr != end);
-	return err;
-}
-
 pte_t * fastcall get_locked_pte(struct mm_struct *mm, unsigned long addr, spinlock_t **ptl)
 {
 	pgd_t * pgd = pgd_offset(mm, addr);
@@ -1717,16 +1628,11 @@ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
 
 	if (unlikely(anon_vma_prepare(vma)))
 		goto oom;
-	if (old_page == ZERO_PAGE(address)) {
-		new_page = alloc_zeroed_user_highpage_movable(vma, address);
-		if (!new_page)
-			goto oom;
-	} else {
-		new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address);
-		if (!new_page)
-			goto oom;
-		cow_user_page(new_page, old_page, address, vma);
-	}
+	VM_BUG_ON(old_page == ZERO_PAGE(0));
+	new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address);
+	if (!new_page)
+		goto oom;
+	cow_user_page(new_page, old_page, address, vma);
 
 	/*
 	 * Re-check the pte - we dropped the lock
@@ -2252,39 +2158,24 @@ static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
 	spinlock_t *ptl;
 	pte_t entry;
 
-	if (write_access) {
-		/* Allocate our own private page. */
-		pte_unmap(page_table);
-
-		if (unlikely(anon_vma_prepare(vma)))
-			goto oom;
-		page = alloc_zeroed_user_highpage_movable(vma, address);
-		if (!page)
-			goto oom;
-
-		entry = mk_pte(page, vma->vm_page_prot);
-		entry = maybe_mkwrite(pte_mkdirty(entry), vma);
+	/* Allocate our own private page. */
+	pte_unmap(page_table);
 
-		page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
-		if (!pte_none(*page_table))
-			goto release;
-		inc_mm_counter(mm, anon_rss);
-		lru_cache_add_active(page);
-		page_add_new_anon_rmap(page, vma, address);
-	} else {
-		/* Map the ZERO_PAGE - vm_page_prot is readonly */
-		page = ZERO_PAGE(address);
-		page_cache_get(page);
-		entry = mk_pte(page, vma->vm_page_prot);
+	if (unlikely(anon_vma_prepare(vma)))
+		goto oom;
+	page = alloc_zeroed_user_highpage_movable(vma, address);
+	if (!page)
+		goto oom;
 
-		ptl = pte_lockptr(mm, pmd);
-		spin_lock(ptl);
-		if (!pte_none(*page_table))
-			goto release;
-		inc_mm_counter(mm, file_rss);
-		page_add_file_rmap(page);
-	}
+	entry = mk_pte(page, vma->vm_page_prot);
+	entry = maybe_mkwrite(pte_mkdirty(entry), vma);
 
+	page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
+	if (!pte_none(*page_table))
+		goto release;
+	inc_mm_counter(mm, anon_rss);
+	lru_cache_add_active(page);
+	page_add_new_anon_rmap(page, vma, address);
 	set_pte_at(mm, address, page_table, entry);
 
 	/* No need to invalidate - it was non-present before */