xen: use vma_lookup() in privcmd_ioctl_mmap()

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 since privcmd_ioctl_mmap() will exit
the loop if vm_start != msg->va.

Link: https://lkml.kernel.org/r/20220404143501.2016403-22-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c
index 3369734108af23724e728531ce4024ea752b7fbc..ad17166b0ef6b39f75e979a1da0533a7997bfefe 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)