X-Git-Url: http://pileus.org/git/?a=blobdiff_plain;f=mm%2Fhugetlb.c;h=65f38c218207231e0bf5b612ccacc5858be1b4e0;hb=ba198098a21a5dc8885fddfb308135bc2f138003;hp=450493d255727c95f92d769353673bfeeb633c92;hpb=bad44b5be84cf3bb1ff900bec02ee61e1993328c;p=~andy%2Flinux

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 450493d2557..65f38c21820 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1278,6 +1278,9 @@ static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count,
 		if (!ret)
 			goto out;
 
+		/* Bail for signals. Probably ctrl-c from user */
+		if (signal_pending(current))
+			goto out;
 	}
 
 	/*
@@ -2237,6 +2240,12 @@ static int unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
 		+ (vma->vm_pgoff >> PAGE_SHIFT);
 	mapping = (struct address_space *)page_private(page);
 
+	/*
+	 * Take the mapping lock for the duration of the table walk. As
+	 * this mapping should be shared between all the VMAs,
+	 * __unmap_hugepage_range() is called as the lock is already held
+	 */
+	spin_lock(&mapping->i_mmap_lock);
 	vma_prio_tree_foreach(iter_vma, &iter, &mapping->i_mmap, pgoff, pgoff) {
 		/* Do not unmap the current VMA */
 		if (iter_vma == vma)
@@ -2250,10 +2259,11 @@ static int unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
 		 * from the time of fork. This would look like data corruption
 		 */
 		if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER))
-			unmap_hugepage_range(iter_vma,
+			__unmap_hugepage_range(iter_vma,
 				address, address + huge_page_size(h),
 				page);
 	}
+	spin_unlock(&mapping->i_mmap_lock);
 
 	return 1;
 }
@@ -2293,6 +2303,9 @@ retry_avoidcopy:
 		outside_reserve = 1;
 
 	page_cache_get(old_page);
+
+	/* Drop page_table_lock as buddy allocator may be called */
+	spin_unlock(&mm->page_table_lock);
 	new_page = alloc_huge_page(vma, address, outside_reserve);
 
 	if (IS_ERR(new_page)) {
@@ -2310,19 +2323,25 @@ retry_avoidcopy:
 			if (unmap_ref_private(mm, vma, old_page, address)) {
 				BUG_ON(page_count(old_page) != 1);
 				BUG_ON(huge_pte_none(pte));
+				spin_lock(&mm->page_table_lock);
 				goto retry_avoidcopy;
 			}
 			WARN_ON_ONCE(1);
 		}
 
+		/* Caller expects lock to be held */
+		spin_lock(&mm->page_table_lock);
 		return -PTR_ERR(new_page);
 	}
 
-	spin_unlock(&mm->page_table_lock);
 	copy_huge_page(new_page, old_page, address, vma);
 	__SetPageUptodate(new_page);
-	spin_lock(&mm->page_table_lock);
 
+	/*
+	 * Retake the page_table_lock to check for racing updates
+	 * before the page tables are altered
+	 */
+	spin_lock(&mm->page_table_lock);
 	ptep = huge_pte_offset(mm, address & huge_page_mask(h));
 	if (likely(pte_same(huge_ptep_get(ptep), pte))) {
 		/* Break COW */