Merge branch 'sh/stable-updates'

6 files changed, 95 insertions, 57 deletions

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 488b644e0e8e..954032b80bed 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2586,7 +2586,7 @@ static int mem_cgroup_force_empty(struct mem_cgroup *mem, bool free_all)
 	if (free_all)
 		goto try_to_free;
 move_account:
-	while (mem->res.usage > 0) {
+	do {
 		ret = -EBUSY;
 		if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children))
 			goto out;
@@ -2614,8 +2614,8 @@ move_account:
 		if (ret == -ENOMEM)
 			goto try_to_free;
 		cond_resched();
-	}
-	ret = 0;
+	/* "ret" should also be checked to ensure all lists are empty. */
+	} while (mem->res.usage > 0 || ret);
 out:
 	css_put(&mem->css);
 	return ret;
@@ -2648,10 +2648,7 @@ try_to_free:
 	}
 	lru_add_drain();
 	/* try move_account...there may be some *locked* pages. */
-	if (mem->res.usage)
-		goto move_account;
-	ret = 0;
-	goto out;
+	goto move_account;
 }
 
 int mem_cgroup_force_empty_write(struct cgroup *cont, unsigned int event)
diff --git a/mm/nommu.c b/mm/nommu.c
index 17773862619b..48a2ecfaf059 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -552,11 +552,11 @@ static void free_page_series(unsigned long from, unsigned long to)
 static void __put_nommu_region(struct vm_region *region)
 	__releases(nommu_region_sem)
 {
-	kenter("%p{%d}", region, atomic_read(&region->vm_usage));
+	kenter("%p{%d}", region, region->vm_usage);
 
 	BUG_ON(!nommu_region_tree.rb_node);
 
-	if (atomic_dec_and_test(&region->vm_usage)) {
+	if (--region->vm_usage == 0) {
 		if (region->vm_top > region->vm_start)
 			delete_nommu_region(region);
 		up_write(&nommu_region_sem);
@@ -1205,7 +1205,7 @@ unsigned long do_mmap_pgoff(struct file *file,
 	if (!vma)
 		goto error_getting_vma;
 
-	atomic_set(&region->vm_usage, 1);
+	region->vm_usage = 1;
 	region->vm_flags = vm_flags;
 	region->vm_pgoff = pgoff;
 
@@ -1272,7 +1272,7 @@ unsigned long do_mmap_pgoff(struct file *file,
 			}
 
 			/* we've found a region we can share */
-			atomic_inc(&pregion->vm_usage);
+			pregion->vm_usage++;
 			vma->vm_region = pregion;
 			start = pregion->vm_start;
 			start += (pgoff - pregion->vm_pgoff) << PAGE_SHIFT;
@@ -1289,7 +1289,7 @@ unsigned long do_mmap_pgoff(struct file *file,
 					vma->vm_region = NULL;
 					vma->vm_start = 0;
 					vma->vm_end = 0;
-					atomic_dec(&pregion->vm_usage);
+					pregion->vm_usage--;
 					pregion = NULL;
 					goto error_just_free;
 				}
@@ -1441,10 +1441,9 @@ int split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
 
 	kenter("");
 
-	/* we're only permitted to split anonymous regions that have a single
-	 * owner */
-	if (vma->vm_file ||
-	    atomic_read(&vma->vm_region->vm_usage) != 1)
+	/* we're only permitted to split anonymous regions (these should have
+	 * only a single usage on the region) */
+	if (vma->vm_file)
 		return -ENOMEM;
 
 	if (mm->map_count >= sysctl_max_map_count)
@@ -1518,7 +1517,7 @@ static int shrink_vma(struct mm_struct *mm,
 
 	/* cut the backing region down to size */
 	region = vma->vm_region;
-	BUG_ON(atomic_read(&region->vm_usage) != 1);
+	BUG_ON(region->vm_usage != 1);
 
 	down_write(&nommu_region_sem);
 	delete_nommu_region(region);
@@ -1762,27 +1761,6 @@ void unmap_mapping_range(struct address_space *mapping,
 EXPORT_SYMBOL(unmap_mapping_range);
 
 /*
- * ask for an unmapped area at which to create a mapping on a file
- */
-unsigned long get_unmapped_area(struct file *file, unsigned long addr,
-				unsigned long len, unsigned long pgoff,
-				unsigned long flags)
-{
-	unsigned long (*get_area)(struct file *, unsigned long, unsigned long,
-				  unsigned long, unsigned long);
-
-	get_area = current->mm->get_unmapped_area;
-	if (file && file->f_op && file->f_op->get_unmapped_area)
-		get_area = file->f_op->get_unmapped_area;
-
-	if (!get_area)
-		return -ENOSYS;
-
-	return get_area(file, addr, len, pgoff, flags);
-}
-EXPORT_SYMBOL(get_unmapped_area);
-
-/*
  * Check that a process has enough memory to allocate a new virtual
  * mapping. 0 means there is enough memory for the allocation to
  * succeed and -ENOMEM implies there is not.
@@ -1936,3 +1914,65 @@ int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, in
 	mmput(mm);
 	return len;
 }
+
+/**
+ * nommu_shrink_inode_mappings - Shrink the shared mappings on an inode
+ * @inode: The inode to check
+ * @size: The current filesize of the inode
+ * @newsize: The proposed filesize of the inode
+ *
+ * Check the shared mappings on an inode on behalf of a shrinking truncate to
+ * make sure that that any outstanding VMAs aren't broken and then shrink the
+ * vm_regions that extend that beyond so that do_mmap_pgoff() doesn't
+ * automatically grant mappings that are too large.
+ */
+int nommu_shrink_inode_mappings(struct inode *inode, size_t size,
+				size_t newsize)
+{
+	struct vm_area_struct *vma;
+	struct prio_tree_iter iter;
+	struct vm_region *region;
+	pgoff_t low, high;
+	size_t r_size, r_top;
+
+	low = newsize >> PAGE_SHIFT;
+	high = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
+
+	down_write(&nommu_region_sem);
+
+	/* search for VMAs that fall within the dead zone */
+	vma_prio_tree_foreach(vma, &iter, &inode->i_mapping->i_mmap,
+			      low, high) {
+		/* found one - only interested if it's shared out of the page
+		 * cache */
+		if (vma->vm_flags & VM_SHARED) {
+			up_write(&nommu_region_sem);
+			return -ETXTBSY; /* not quite true, but near enough */
+		}
+	}
+
+	/* reduce any regions that overlap the dead zone - if in existence,
+	 * these will be pointed to by VMAs that don't overlap the dead zone
+	 *
+	 * we don't check for any regions that start beyond the EOF as there
+	 * shouldn't be any
+	 */
+	vma_prio_tree_foreach(vma, &iter, &inode->i_mapping->i_mmap,
+			      0, ULONG_MAX) {
+		if (!(vma->vm_flags & VM_SHARED))
+			continue;
+
+		region = vma->vm_region;
+		r_size = region->vm_top - region->vm_start;
+		r_top = (region->vm_pgoff << PAGE_SHIFT) + r_size;
+
+		if (r_top > newsize) {
+			region->vm_top -= r_top - newsize;
+			if (region->vm_end > region->vm_top)
+				region->vm_end = region->vm_top;
+		}
+	}
+
+	up_write(&nommu_region_sem);
+	return 0;
+}
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 4e9f5cc5fb59..d2a8889b4c58 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1222,10 +1222,10 @@ again:
 		}
 		spin_lock_irqsave(&zone->lock, flags);
 		page = __rmqueue(zone, order, migratetype);
-		__mod_zone_page_state(zone, NR_FREE_PAGES, -(1 << order));
 		spin_unlock(&zone->lock);
 		if (!page)
 			goto failed;
+		__mod_zone_page_state(zone, NR_FREE_PAGES, -(1 << order));
 	}
 
 	__count_zone_vm_events(PGALLOC, zone, 1 << order);
@@ -3998,7 +3998,7 @@ void __init add_active_range(unsigned int nid, unsigned long start_pfn,
 		}
 
 		/* Merge backward if suitable */
-		if (start_pfn < early_node_map[i].end_pfn &&
+		if (start_pfn < early_node_map[i].start_pfn &&
 				end_pfn >= early_node_map[i].start_pfn) {
 			early_node_map[i].start_pfn = start_pfn;
 			return;
diff --git a/mm/truncate.c b/mm/truncate.c
index 342deee22684..e87e37244829 100644
--- a/mm/truncate.c
+++ b/mm/truncate.c
@@ -522,22 +522,20 @@ EXPORT_SYMBOL_GPL(invalidate_inode_pages2);
  */
 void truncate_pagecache(struct inode *inode, loff_t old, loff_t new)
 {
-	if (new < old) {
-		struct address_space *mapping = inode->i_mapping;
-
-		/*
-		 * unmap_mapping_range is called twice, first simply for
-		 * efficiency so that truncate_inode_pages does fewer
-		 * single-page unmaps.  However after this first call, and
-		 * before truncate_inode_pages finishes, it is possible for
-		 * private pages to be COWed, which remain after
-		 * truncate_inode_pages finishes, hence the second
-		 * unmap_mapping_range call must be made for correctness.
-		 */
-		unmap_mapping_range(mapping, new + PAGE_SIZE - 1, 0, 1);
-		truncate_inode_pages(mapping, new);
-		unmap_mapping_range(mapping, new + PAGE_SIZE - 1, 0, 1);
-	}
+	struct address_space *mapping = inode->i_mapping;
+
+	/*
+	 * unmap_mapping_range is called twice, first simply for
+	 * efficiency so that truncate_inode_pages does fewer
+	 * single-page unmaps.  However after this first call, and
+	 * before truncate_inode_pages finishes, it is possible for
+	 * private pages to be COWed, which remain after
+	 * truncate_inode_pages finishes, hence the second
+	 * unmap_mapping_range call must be made for correctness.
+	 */
+	unmap_mapping_range(mapping, new + PAGE_SIZE - 1, 0, 1);
+	truncate_inode_pages(mapping, new);
+	unmap_mapping_range(mapping, new + PAGE_SIZE - 1, 0, 1);
 }
 EXPORT_SYMBOL(truncate_pagecache);
 
diff --git a/mm/util.c b/mm/util.c
index 7c35ad95f927..834db7be240f 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -220,7 +220,7 @@ char *strndup_user(const char __user *s, long n)
 }
 EXPORT_SYMBOL(strndup_user);
 
-#ifndef HAVE_ARCH_PICK_MMAP_LAYOUT
+#if defined(CONFIG_MMU) && !defined(HAVE_ARCH_PICK_MMAP_LAYOUT)
 void arch_pick_mmap_layout(struct mm_struct *mm)
 {
 	mm->mmap_base = TASK_UNMAPPED_BASE;
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 885207a6b6b7..c26986c85ce0 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1922,6 +1922,9 @@ static int sleeping_prematurely(pg_data_t *pgdat, int order, long remaining)
 		if (!populated_zone(zone))
 			continue;
 
+		if (zone_is_all_unreclaimable(zone))
+			continue;
+
 		if (!zone_watermark_ok(zone, order, high_wmark_pages(zone),
 								0, 0))
 			return 1;