On 11/28/18 3:25 AM, Markus Armbruster wrote:
xiezhide <xiezh...@huawei.com> writes:

Rename the ThrottleLimits member names and modify related code

Signed-off-by: xiezhide <xiezh...@huawei.com>
---
  qapi/block-core.json |  70 +++++++++++-----------
  util/throttle.c      | 163 +++++++++++++++++++++++++--------------------------
  2 files changed, 116 insertions(+), 117 deletions(-)

diff --git a/qapi/block-core.json b/qapi/block-core.json
index d4fe710..4ffaaea 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json

  ##
  { 'struct': 'ThrottleLimits',
-  'data': { '*iops-total' : 'int', '*iops-total-max' : 'int',

+  'data': { '*iops' : 'int', '*iops_max' : 'int',
+            '*iops_max_length' : 'int', '*iops_rd' : 'int',
+            '*iops_rd_max' : 'int', '*iops_rd_max_length' : 'int',
+            '*iops_wr' : 'int', '*iops_wr_max' : 'int',
+            '*iops_wr_max_length' : 'int', '*bps' : 'int',
+            '*bps_max' : 'int', '*bps_max_length' : 'int',
+            '*bps_rd' : 'int', '*bps_rd_max' : 'int',
+            '*bps_rd_max_length' : 'int', '*bps_wr' : 'int',
+            '*bps_wr_max' : 'int', '*bps_wr_max_length' : 'int',
+            '*iops_size' : 'int' } }

Compatibility break.  Why is that okay?

Grepping qapi/qapi-introspection.c shows 0 hits for either ThrottleLimits or for iops-total, so there are no QMP commands affected. There might, however, be command line and/or QOM paths affected, which is harder to audit since those don't affect instrospection.


Even if it is, you still run afoul of docs/devel/qapi-code-gen.txt:

     Command names, and member names within a type, should be all lower
     case with words separated by a hyphen.  However, some existing older
     commands and complex types use underscore; when extending such
     expressions, consistency is preferred over blindly avoiding
     underscore.

The exception doesn't apply here.

Ah, but it does, because we are refactoring code to share a common QAPI struct in a later patch, where we need this exact naming to avoid breaking that command.

So the REAL problem with this commit is that the commit message does not give enough details, either why this is safe (because it does not impact existing QMP commands) or needed (because we will be using it to rewrite an existing QMP command that needs this spelling).

--
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org

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