X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=mm%2Fmadvise.c;h=35b1479b7c9d080ed97b772da44603c4f757093c;hb=23ce932a5e3ec3b9f06e92c8797d834d43abfb0f;hp=36d6ea2b63405a8bd682b1e225bb3f748de2eda5;hpb=a425a638c858fd10370b573bde81df3ba500e271;p=safe%2Fjmp%2Flinux-2.6

diff --git a/mm/madvise.c b/mm/madvise.c
index 36d6ea2..35b1479 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -11,6 +11,7 @@
 #include <linux/mempolicy.h>
 #include <linux/hugetlb.h>
 #include <linux/sched.h>
+#include <linux/ksm.h>
 
 /*
  * Any behaviour which results in changes to the vma->vm_flags needs to
@@ -41,7 +42,7 @@ static long madvise_behavior(struct vm_area_struct * vma,
 	struct mm_struct * mm = vma->vm_mm;
 	int error = 0;
 	pgoff_t pgoff;
-	int new_flags = vma->vm_flags;
+	unsigned long new_flags = vma->vm_flags;
 
 	switch (behavior) {
 	case MADV_NORMAL:
@@ -57,8 +58,18 @@ static long madvise_behavior(struct vm_area_struct * vma,
 		new_flags |= VM_DONTCOPY;
 		break;
 	case MADV_DOFORK:
+		if (vma->vm_flags & VM_IO) {
+			error = -EINVAL;
+			goto out;
+		}
 		new_flags &= ~VM_DONTCOPY;
 		break;
+	case MADV_MERGEABLE:
+	case MADV_UNMERGEABLE:
+		error = ksm_madvise(vma, start, end, behavior, &new_flags);
+		if (error)
+			goto out;
+		break;
 	}
 
 	if (new_flags == vma->vm_flags) {
@@ -112,14 +123,6 @@ static long madvise_willneed(struct vm_area_struct * vma,
 	if (!file)
 		return -EBADF;
 
-	/*
-	 * Page cache readahead assumes page cache pages are order-0 which
-	 * is not the case for hugetlbfs. Do not give a bad return value
-	 * but ignore the advice.
-	 */
-	if (vma->vm_flags & VM_HUGETLB)
-		return 0;
-
 	if (file->f_mapping->a_ops->get_xip_mem) {
 		/* no bad return value, but ignore advice */
 		return 0;
@@ -131,8 +134,7 @@ static long madvise_willneed(struct vm_area_struct * vma,
 		end = vma->vm_end;
 	end = ((end - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
 
-	force_page_cache_readahead(file->f_mapping,
-			file, start, max_sane_readahead(end - start));
+	force_page_cache_readahead(file->f_mapping, file, start, end - start);
 	return 0;
 }
 
@@ -216,41 +218,69 @@ static long madvise_remove(struct vm_area_struct *vma,
 	return error;
 }
 
+#ifdef CONFIG_MEMORY_FAILURE
+/*
+ * Error injection support for memory error handling.
+ */
+static int madvise_hwpoison(unsigned long start, unsigned long end)
+{
+	int ret = 0;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+	for (; start < end; start += PAGE_SIZE) {
+		struct page *p;
+		int ret = get_user_pages(current, current->mm, start, 1,
+						0, 0, &p, NULL);
+		if (ret != 1)
+			return ret;
+		printk(KERN_INFO "Injecting memory failure for page %lx at %lx\n",
+		       page_to_pfn(p), start);
+		/* Ignore return value for now */
+		__memory_failure(page_to_pfn(p), 0, 1);
+		put_page(p);
+	}
+	return ret;
+}
+#endif
+
 static long
 madvise_vma(struct vm_area_struct *vma, struct vm_area_struct **prev,
 		unsigned long start, unsigned long end, int behavior)
 {
-	long error;
+	switch (behavior) {
+	case MADV_REMOVE:
+		return madvise_remove(vma, prev, start, end);
+	case MADV_WILLNEED:
+		return madvise_willneed(vma, prev, start, end);
+	case MADV_DONTNEED:
+		return madvise_dontneed(vma, prev, start, end);
+	default:
+		return madvise_behavior(vma, prev, start, end, behavior);
+	}
+}
 
+static int
+madvise_behavior_valid(int behavior)
+{
 	switch (behavior) {
 	case MADV_DOFORK:
-		if (vma->vm_flags & VM_IO) {
-			error = -EINVAL;
-			break;
-		}
 	case MADV_DONTFORK:
 	case MADV_NORMAL:
 	case MADV_SEQUENTIAL:
 	case MADV_RANDOM:
-		error = madvise_behavior(vma, prev, start, end, behavior);
-		break;
 	case MADV_REMOVE:
-		error = madvise_remove(vma, prev, start, end);
-		break;
-
 	case MADV_WILLNEED:
-		error = madvise_willneed(vma, prev, start, end);
-		break;
-
 	case MADV_DONTNEED:
-		error = madvise_dontneed(vma, prev, start, end);
-		break;
+#ifdef CONFIG_KSM
+	case MADV_MERGEABLE:
+	case MADV_UNMERGEABLE:
+#endif
+		return 1;
 
 	default:
-		error = -EINVAL;
-		break;
+		return 0;
 	}
-	return error;
 }
 
 /*
@@ -277,6 +307,12 @@ madvise_vma(struct vm_area_struct *vma, struct vm_area_struct **prev,
  *		so the kernel can free resources associated with it.
  *  MADV_REMOVE - the application wants to free up the given range of
  *		pages and associated backing store.
+ *  MADV_DONTFORK - omit this area from child's address space when forking:
+ *		typically, to avoid COWing pages pinned by get_user_pages().
+ *  MADV_DOFORK - cancel MADV_DONTFORK: no longer omit this area when forking.
+ *  MADV_MERGEABLE - the application recommends that KSM try to merge pages in
+ *		this area with pages of identical content from other such areas.
+ *  MADV_UNMERGEABLE- cancel MADV_MERGEABLE: no longer merge pages with others.
  *
  * return values:
  *  zero    - success
@@ -298,6 +334,13 @@ SYSCALL_DEFINE3(madvise, unsigned long, start, size_t, len_in, int, behavior)
 	int write;
 	size_t len;
 
+#ifdef CONFIG_MEMORY_FAILURE
+	if (behavior == MADV_HWPOISON)
+		return madvise_hwpoison(start, start+len_in);
+#endif
+	if (!madvise_behavior_valid(behavior))
+		return error;
+
 	write = madvise_need_mmap_write(behavior);
 	if (write)
 		down_write(&current->mm->mmap_sem);