xen/privcmd: Optimized privcmd_ioctl_mmap() by using vma_lookup()

vma_lookup() walks the VMA tree for a specific value, find_vma() will
search the tree after walking to a specific value.  It is more efficient
to only walk to the requested value as this case requires the address to
equal the vm_start.

Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>

diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c
index 720a7b7abd46d690f2ed86f544064403ab4f1647..5f903ae9af7e8579145cc22ce1c54054398fb825 100644 (file)
--- a/drivers/xen/privcmd.c
+++ b/drivers/xen/privcmd.c
@@ -282,7 +282,7 @@ static long privcmd_ioctl_mmap(struct file *file, void __user *udata)
                                                     struct page, lru);
                struct privcmd_mmap_entry *msg = page_address(page);
 
-               vma = find_vma(mm, msg->va);
+               vma = vma_lookup(mm, msg->va);
                rc = -EINVAL;
 
                if (!vma || (msg->va != vma->vm_start) || vma->vm_private_data)