blk-mq: really fix plug list flushing for nomerge queues

[linux-2.6-block.git] / mm / util.c

diff --git a/mm/util.c b/mm/util.c
index 6cc81e7b870523342cb8882ba222149644d894ac..917e0e3d0f8ee3a05edf78a665eace20635b3aa0 100644 (file)
--- a/mm/util.c
+++ b/mm/util.c
@@ -297,7 +297,8 @@ unsigned long vm_mmap_pgoff(struct file *file, unsigned long addr,
 
        ret = security_mmap_file(file, prot, flag);
        if (!ret) {
-               down_write(&mm->mmap_sem);
+               if (down_write_killable(&mm->mmap_sem))
+                       return -EINTR;
                ret = do_mmap_pgoff(file, addr, len, prot, flag, pgoff,
                                    &populate);
                up_write(&mm->mmap_sem);
@@ -346,6 +347,29 @@ void *page_rmapping(struct page *page)
        return __page_rmapping(page);
 }
 
+/*
+ * Return true if this page is mapped into pagetables.
+ * For compound page it returns true if any subpage of compound page is mapped.
+ */
+bool page_mapped(struct page *page)
+{
+       int i;
+
+       if (likely(!PageCompound(page)))
+               return atomic_read(&page->_mapcount) >= 0;
+       page = compound_head(page);
+       if (atomic_read(compound_mapcount_ptr(page)) >= 0)
+               return true;
+       if (PageHuge(page))
+               return false;
+       for (i = 0; i < hpage_nr_pages(page); i++) {
+               if (atomic_read(&page[i]._mapcount) >= 0)
+                       return true;
+       }
+       return false;
+}
+EXPORT_SYMBOL(page_mapped);
+
 struct anon_vma *page_anon_vma(struct page *page)
 {
        unsigned long mapping;