X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=mm%2Fmadvise.c;h=0439c560e0b4ceb474c4e981aa71ddaa2708f77b;hb=d939d46ba7caa14e960be18e18f5c07be8806d7a;hp=81c4ea30c75e60b9001127697045d000ae075fd1;hpb=86090fcac5e27b630656fe3d963a6b80e26dac44;p=linux-2.6.git

diff --git a/mm/madvise.c b/mm/madvise.c
index 81c4ea30c..0439c560e 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -31,7 +31,9 @@ static long madvise_behavior(struct vm_area_struct * vma, unsigned long start,
 			return -EAGAIN;
 	}
 
-	spin_lock(&mm->page_table_lock);
+	/*
+	 * vm_flags is protected by the mmap_sem held in write mode.
+	 */
 	VM_ClearReadHint(vma);
 
 	switch (behavior) {
@@ -44,7 +46,6 @@ static long madvise_behavior(struct vm_area_struct * vma, unsigned long start,
 	default:
 		break;
 	}
-	spin_unlock(&mm->page_table_lock);
 
 	return 0;
 }
@@ -92,16 +93,14 @@ static long madvise_willneed(struct vm_area_struct * vma,
 static long madvise_dontneed(struct vm_area_struct * vma,
 			     unsigned long start, unsigned long end)
 {
-	struct zap_details details;
-
 	if (vma->vm_flags & VM_LOCKED)
 		return -EINVAL;
 
 	if (unlikely(vma->vm_flags & VM_NONLINEAR)) {
-		details.check_mapping = NULL;
-		details.nonlinear_vma = vma;
-		details.first_index = 0;
-		details.last_index = ULONG_MAX;
+		struct zap_details details = {
+			.nonlinear_vma = vma,
+			.last_index = ULONG_MAX,
+		};
 		zap_page_range(vma, start, end - start, &details);
 	} else
 		zap_page_range(vma, start, end - start, NULL);
@@ -170,18 +169,24 @@ static long madvise_vma(struct vm_area_struct * vma, unsigned long start,
  *  -EBADF  - map exists, but area maps something that isn't a file.
  *  -EAGAIN - a kernel resource was temporarily unavailable.
  */
-asmlinkage long sys_madvise(unsigned long start, size_t len, int behavior)
+asmlinkage long sys_madvise(unsigned long start, size_t len_in, int behavior)
 {
 	unsigned long end;
 	struct vm_area_struct * vma;
 	int unmapped_error = 0;
 	int error = -EINVAL;
+	size_t len;
 
 	down_write(&current->mm->mmap_sem);
 
 	if (start & ~PAGE_MASK)
 		goto out;
-	len = (len + ~PAGE_MASK) & PAGE_MASK;
+	len = (len_in + ~PAGE_MASK) & PAGE_MASK;
+
+	/* Check to see whether len was rounded up from small -ve to zero */
+	if (len_in && !len)
+		goto out;
+
 	end = start + len;
 	if (end < start)
 		goto out;