Implement zap_vma_ptes() for managed device objects.

Reviewed by:	markj
Discussed with:	hselasky
Tested by:	zeising
MFC after:	1 week
Sponsored by:	Mellanox Technologies
Differential revision:	https://reviews.freebsd.org/D18606

2 files changed, 21 insertions, 6 deletions

diff --git a/sys/compat/linuxkpi/common/include/linux/mm.h b/sys/compat/linuxkpi/common/include/linux/mm.h
index c127697fb2c6..26bd01b6e623 100644
--- a/sys/compat/linuxkpi/common/include/linux/mm.h
+++ b/sys/compat/linuxkpi/common/include/linux/mm.h
@@ -180,12 +180,8 @@ apply_to_page_range(struct mm_struct *mm, unsigned long address,
 	return (-ENOTSUP);
 }
 
-static inline int
-zap_vma_ptes(struct vm_area_struct *vma, unsigned long address,
-    unsigned long size)
-{
-	return (-ENOTSUP);
-}
+int zap_vma_ptes(struct vm_area_struct *vma, unsigned long address,
+    unsigned long size);
 
 static inline int
 remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
diff --git a/sys/compat/linuxkpi/common/src/linux_compat.c b/sys/compat/linuxkpi/common/src/linux_compat.c
index 3953d1634629..297c6d8e01d8 100644
--- a/sys/compat/linuxkpi/common/src/linux_compat.c
+++ b/sys/compat/linuxkpi/common/src/linux_compat.c
@@ -672,6 +672,25 @@ static struct cdev_pager_ops linux_cdev_pager_ops[2] = {
   },
 };
 
+int
+zap_vma_ptes(struct vm_area_struct *vma, unsigned long address,
+    unsigned long size)
+{
+	vm_object_t obj;
+	vm_page_t m;
+
+	obj = vma->vm_obj;
+	if (obj == NULL || (obj->flags & OBJ_UNMANAGED) != 0)
+		return (-ENOTSUP);
+	VM_OBJECT_RLOCK(obj);
+	for (m = vm_page_find_least(obj, OFF_TO_IDX(address));
+	    m != NULL && m->pindex < OFF_TO_IDX(address + size);
+	    m = TAILQ_NEXT(m, listq))
+		pmap_remove_all(m);
+	VM_OBJECT_RUNLOCK(obj);
+	return (0);
+}
+
 #define	OPW(fp,td,code) ({			\
 	struct file *__fpop;			\
 	__typeof(code) __retval;		\