[xen staging] tools/xenstored: Propagate correctly the error message from lu_start()

[patchbot@xxxxxxx]

commit 604551fb763c4c70123f642a9b2866890790e2b2
Author:     Julien Grall <jgrall@xxxxxxxxxx>
AuthorDate: Thu Jul 29 12:06:02 2021 +0100
Commit:     Ian Jackson <iwj@xxxxxxxxxxxxxx>
CommitDate: Fri Jul 30 11:02:46 2021 +0100

    tools/xenstored: Propagate correctly the error message from lu_start()
    
    lu_start() will only set errno when it returns NULL. For all the
    other cases, the value is unknown.
    
    This means that when lu_start() returns an error message, it may not
    be propagated to the client.
    
    The check that errno is a non-zero value is now dropped and instead
    the value is returned when no error message is provided. This
    relies on errno to always be set when ret == NULL.
    
    Fixes: af216a99fb ("tools/xenstore: add the basic framework for doing the 
live update")
    Signed-off-by: Julien Grall <jgrall@xxxxxxxxxx>
    Reviewed-by: Juergen Gross <jgross@xxxxxxxx>
---
 tools/xenstore/xenstored_control.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/tools/xenstore/xenstored_control.c 
b/tools/xenstore/xenstored_control.c
index ff9863c17f..6b68b79faa 100644
--- a/tools/xenstore/xenstored_control.c
+++ b/tools/xenstore/xenstored_control.c
@@ -795,10 +795,8 @@ static int do_control_lu(void *ctx, struct connection 
*conn,
                                return EINVAL;
                }
                ret = lu_start(ctx, conn, force, to);
-               if (errno)
-                       return errno;
                if (!ret)
-                       return 0;
+                       return errno;
        } else {
                errno = 0;
                ret = lu_arch(ctx, conn, vec, num);
--
generated by git-patchbot for /home/xen/git/xen.git#staging