# HG changeset patch
# User lively@dlively2
# Node ID 2d63622421e93895f9f5c99d900e80e78943b0c6
# Parent  0b79b3c194b17dcf4d7916e33628feb321cc1e05
Robert's workaround for the infamous Eeek! page_mapcount(page) went negative! bug.

[Bug id:] 3914

[Reviewed By:] Ben & Dave L

diff -r 0b79b3c194b1 -r 2d63622421e9 linux-2.6-xen-sparse/drivers/xen/privcmd/privcmd.c
--- a/linux-2.6-xen-sparse/drivers/xen/privcmd/privcmd.c	Sat Jun 10 13:23:11 2006 -0400
+++ b/linux-2.6-xen-sparse/drivers/xen/privcmd/privcmd.c	Tue Jun 13 11:05:44 2006 -0400
@@ -244,7 +244,7 @@ static int privcmd_mmap(struct file * fi
 static int privcmd_mmap(struct file * file, struct vm_area_struct * vma)
 {
 	/* DONTCOPY is essential for Xen as copy_page_range is broken. */
-	vma->vm_flags |= VM_RESERVED | VM_IO | VM_DONTCOPY;
+	vma->vm_flags |= VM_RESERVED | VM_IO | VM_DONTCOPY | VM_PRIVCMD;
 
 	return 0;
 }
diff -r 0b79b3c194b1 -r 2d63622421e9 linux-2.6-xen-sparse/include/linux/mm.h
--- a/linux-2.6-xen-sparse/include/linux/mm.h	Sat Jun 10 13:23:11 2006 -0400
+++ b/linux-2.6-xen-sparse/include/linux/mm.h	Tue Jun 13 11:05:44 2006 -0400
@@ -169,6 +169,7 @@ extern unsigned int kobjsize(const void 
 #ifdef CONFIG_XEN
 #define VM_FOREIGN	0x04000000	/* Has pages belonging to another VM */
 #endif
+#define VM_PRIVCMD      0x08000000      /* Pages belong to privcmd mmap */
 
 #ifndef VM_STACK_DEFAULT_FLAGS		/* arch can override this */
 #define VM_STACK_DEFAULT_FLAGS VM_DATA_DEFAULT_FLAGS
diff -r 0b79b3c194b1 -r 2d63622421e9 linux-2.6-xen-sparse/mm/memory.c
--- a/linux-2.6-xen-sparse/mm/memory.c	Sat Jun 10 13:23:11 2006 -0400
+++ b/linux-2.6-xen-sparse/mm/memory.c	Tue Jun 13 11:05:44 2006 -0400
@@ -409,6 +409,10 @@ struct page *vm_normal_page(struct vm_ar
 			print_bad_pte(vma, pte, addr);
 		return NULL;
 	}
+
+        /* This vma points to foreign pages */
+        if (vma->vm_flags & VM_PRIVCMD)
+            return NULL;
 
 	/*
 	 * NOTE! We still have PageReserved() pages in the page