commit 786a4ea82ec9c87e3a895cf41081029b285a5fe5
author Stefan Hajnoczi <stefanha@redhat.com> Mon Mar 23 15:29:26 2015 +0000
committer Kevin Wolf <kwolf@redhat.com> Tue Apr 28 15:36:08 2015 +0200
tree fe42f1059c13ea9a27bc9515e5d440d3bb354773
parent 5863d374a32c98a7adb4c5e49d62de3cdc16d2ea

Convert (ffs(val) - 1) to ctz32(val)

This commit was generated mechanically by coccinelle from the following
semantic patch:

@@
expression val;
@@
- (ffs(val) - 1)
+ ctz32(val)

The call sites have been audited to ensure the ffs(0) - 1 == -1 case
never occurs (due to input validation, asserts, etc).  Therefore we
don't need to worry about the fact that ctz32(0) == 32.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1427124571-28598-5-git-send-email-stefanha@redhat.com
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

block/rbd.c

diff --git a/block/rbd.c b/block/rbd.c
index f3ab2dd..fbe87e0 100644
--- a/block/rbd.c
+++ b/block/rbd.c
@@ -325,7 +325,7 @@
             error_setg(errp, "obj size too small");
             return -EINVAL;
         }
-        obj_order = ffs(objsize) - 1;
+        obj_order = ctz32(objsize);
     }
 
     clientname = qemu_rbd_parse_clientname(conf, clientname_buf);