From c2d45457e6334ddbb4ba7a818cb827906e9136a4 Mon Sep 17 00:00:00 2001
From: Adam Litke <agl@us.ibm.com>
Date: Sat, 29 Oct 2005 18:16:47 -0700
Subject: [PATCH] --- yaml --- r: 11383 b: refs/heads/master c:
 2e9b367c2273ed21c9852a04d90944d472c4f3e6 h: refs/heads/master i:   11381:
 c88c26abc9d37c648a45133272a763ef8ff616a6   11379:
 6669426a004cd8a2203666ec046b8cb576ddd65e   11375:
 e0848baa150fae04bd184172af05e681152fcc30 v: v3

---
 [refs]                     |  2 +-
 trunk/fs/hugetlbfs/inode.c | 63 ++++++++++++++++++++++++++++++++------
 2 files changed, 54 insertions(+), 11 deletions(-)

diff --git a/[refs] b/[refs]
index d1967066a439..071bf4b652e1 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 4c887265977213985091476be40ab11dfdcb4caf
+refs/heads/master: 2e9b367c2273ed21c9852a04d90944d472c4f3e6
diff --git a/trunk/fs/hugetlbfs/inode.c b/trunk/fs/hugetlbfs/inode.c
index 2627efe767cf..e026c807e6b3 100644
--- a/trunk/fs/hugetlbfs/inode.c
+++ b/trunk/fs/hugetlbfs/inode.c
@@ -45,9 +45,58 @@ static struct backing_dev_info hugetlbfs_backing_dev_info = {
 
 int sysctl_hugetlb_shm_group;
 
+static void huge_pagevec_release(struct pagevec *pvec)
+{
+	int i;
+
+	for (i = 0; i < pagevec_count(pvec); ++i)
+		put_page(pvec->pages[i]);
+
+	pagevec_reinit(pvec);
+}
+
+/*
+ * huge_pages_needed tries to determine the number of new huge pages that
+ * will be required to fully populate this VMA.  This will be equal to
+ * the size of the VMA in huge pages minus the number of huge pages
+ * (covered by this VMA) that are found in the page cache.
+ *
+ * Result is in bytes to be compatible with is_hugepage_mem_enough()
+ */
+unsigned long
+huge_pages_needed(struct address_space *mapping, struct vm_area_struct *vma)
+{
+	int i;
+	struct pagevec pvec;
+	unsigned long start = vma->vm_start;
+	unsigned long end = vma->vm_end;
+	unsigned long hugepages = (end - start) >> HPAGE_SHIFT;
+	pgoff_t next = vma->vm_pgoff;
+	pgoff_t endpg = next + ((end - start) >> PAGE_SHIFT);
+
+	pagevec_init(&pvec, 0);
+	while (next < endpg) {
+		if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE))
+			break;
+		for (i = 0; i < pagevec_count(&pvec); i++) {
+			struct page *page = pvec.pages[i];
+			if (page->index > next)
+				next = page->index;
+			if (page->index >= endpg)
+				break;
+			next++;
+			hugepages--;
+		}
+		huge_pagevec_release(&pvec);
+	}
+	return hugepages << HPAGE_SHIFT;
+}
+
 static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
 {
 	struct inode *inode = file->f_dentry->d_inode;
+	struct address_space *mapping = inode->i_mapping;
+	unsigned long bytes;
 	loff_t len, vma_len;
 	int ret;
 
@@ -66,6 +115,10 @@ static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
 	if (vma->vm_end - vma->vm_start < HPAGE_SIZE)
 		return -EINVAL;
 
+	bytes = huge_pages_needed(mapping, vma);
+	if (!is_hugepage_mem_enough(bytes))
+		return -ENOMEM;
+
 	vma_len = (loff_t)(vma->vm_end - vma->vm_start);
 
 	down(&inode->i_sem);
@@ -168,16 +221,6 @@ static int hugetlbfs_commit_write(struct file *file,
 	return -EINVAL;
 }
 
-static void huge_pagevec_release(struct pagevec *pvec)
-{
-	int i;
-
-	for (i = 0; i < pagevec_count(pvec); ++i)
-		put_page(pvec->pages[i]);
-
-	pagevec_reinit(pvec);
-}
-
 static void truncate_huge_page(struct page *page)
 {
 	clear_page_dirty(page);