[Xen-devel] [patch 1/2] xen-gntdev: return -EFAULT on copy_to_user failure

[Dan Carpenter <error27@xxxxxxxxx>]

copy_to_user() returns the amount of data remaining to be copied.  We
want to return a negative error code here.  The upper layers just
call WARN_ON() if we return non-zero so this doesn't change the
behavior.  But returning -EFAULT is still cleaner.

Signed-off-by: Dan Carpenter <error27@xxxxxxxxx>

diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
index 017ce60..b0f9e8f 100644
--- a/drivers/xen/gntdev.c
+++ b/drivers/xen/gntdev.c
@@ -273,7 +273,7 @@ static int __unmap_grant_pages(struct grant_map *map, int 
offset, int pages)
                                map->vma->vm_start + map->notify.addr;
                        err = copy_to_user(tmp, &err, 1);
                        if (err)
-                               return err;
+                               return -EFAULT;
                        map->notify.flags &= ~UNMAP_NOTIFY_CLEAR_BYTE;
                } else if (pgno >= offset && pgno < offset + pages) {
                        uint8_t *tmp = kmap(map->pages[pgno]);

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