1 files changed, 16 insertions, 9 deletions

diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 789b6adbef37..24de8b65fdbd 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -126,8 +126,6 @@ static void background_writeout(unsigned long _min_pages);
 static struct prop_descriptor vm_completions;
 static struct prop_descriptor vm_dirties;
 
-static unsigned long determine_dirtyable_memory(void);
-
 /*
  * couple the period to the dirty_ratio:
  *
@@ -347,7 +345,13 @@ static unsigned long highmem_dirtyable_memory(unsigned long total)
 #endif
 }
 
-static unsigned long determine_dirtyable_memory(void)
+/**
+ * determine_dirtyable_memory - amount of memory that may be used
+ *
+ * Returns the numebr of pages that can currently be freed and used
+ * by the kernel for direct mappings.
+ */
+unsigned long determine_dirtyable_memory(void)
 {
         unsigned long x;
 
@@ -956,6 +960,9 @@ retry:
         }
         if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
                 mapping->writeback_index = index;
+
+        if (wbc->range_cont)
+                wbc->range_start = index << PAGE_CACHE_SHIFT;
         return ret;
 }
 EXPORT_SYMBOL(write_cache_pages);
@@ -1081,7 +1088,7 @@ int __set_page_dirty_nobuffers(struct page *page)
                 if (!mapping)
                         return 1;
 
-                write_lock_irq(&mapping->tree_lock);
+                spin_lock_irq(&mapping->tree_lock);
                 mapping2 = page_mapping(page);
                 if (mapping2) { /* Race with truncate? */
                         BUG_ON(mapping2 != mapping);
@@ -1095,7 +1102,7 @@ int __set_page_dirty_nobuffers(struct page *page)
                         radix_tree_tag_set(&mapping->page_tree,
                                 page_index(page), PAGECACHE_TAG_DIRTY);
                 }
-                write_unlock_irq(&mapping->tree_lock);
+                spin_unlock_irq(&mapping->tree_lock);
                 if (mapping->host) {
                         /* !PageAnon && !swapper_space */
                         __mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
@@ -1251,7 +1258,7 @@ int test_clear_page_writeback(struct page *page)
                 struct backing_dev_info *bdi = mapping->backing_dev_info;
                 unsigned long flags;
 
-                write_lock_irqsave(&mapping->tree_lock, flags);
+                spin_lock_irqsave(&mapping->tree_lock, flags);
                 ret = TestClearPageWriteback(page);
                 if (ret) {
                         radix_tree_tag_clear(&mapping->page_tree,
@@ -1262,7 +1269,7 @@ int test_clear_page_writeback(struct page *page)
                                 __bdi_writeout_inc(bdi);
                         }
                 }
-                write_unlock_irqrestore(&mapping->tree_lock, flags);
+                spin_unlock_irqrestore(&mapping->tree_lock, flags);
         } else {
                 ret = TestClearPageWriteback(page);
         }
@@ -1280,7 +1287,7 @@ int test_set_page_writeback(struct page *page)
                 struct backing_dev_info *bdi = mapping->backing_dev_info;
                 unsigned long flags;
 
-                write_lock_irqsave(&mapping->tree_lock, flags);
+                spin_lock_irqsave(&mapping->tree_lock, flags);
                 ret = TestSetPageWriteback(page);
                 if (!ret) {
                         radix_tree_tag_set(&mapping->page_tree,
@@ -1293,7 +1300,7 @@ int test_set_page_writeback(struct page *page)
                         radix_tree_tag_clear(&mapping->page_tree,
                                                 page_index(page),
                                                 PAGECACHE_TAG_DIRTY);
-                write_unlock_irqrestore(&mapping->tree_lock, flags);
+                spin_unlock_irqrestore(&mapping->tree_lock, flags);
         } else {
                 ret = TestSetPageWriteback(page);
         }