Re: [Qemu-devel] [PATCH v2 3/7] block/qapi: Move 'aio' option to file driver

[Max Reitz]

On 27.09.2016 10:20, Kevin Wolf wrote:
> Am 26.09.2016 um 18:49 hat Max Reitz geschrieben:
>> On 23.09.2016 16:32, Kevin Wolf wrote:
>>> The option whether or not to use a native AIO interface really isn't a
>>> generic option for all drivers, but only applies to the native file
>>> protocols. This patch moves the option in blockdev-add to the
>>> appropriate places (raw-posix and raw-win32).
>>>
>>> We still have to keep the flag BDRV_O_NATIVE_AIO for compatibility
>>> because so far the AIO option was usually specified on the wrong layer
>>> (the top-level format driver, which didn't even look at it) and then
>>> inherited by the protocol driver (where it was actually used). We can't
>>> forbid this use except in new interfaces.
>>>
>>> Signed-off-by: Kevin Wolf <address@hidden>
>>> ---
>>>  block/raw-posix.c      | 44 ++++++++++++++++++++++++---------------
>>>  block/raw-win32.c      | 56 
>>> +++++++++++++++++++++++++++++++++++++++++++++-----
>>>  qapi/block-core.json   |  6 +++---
>>>  tests/qemu-iotests/087 |  4 ++--
>>>  4 files changed, 83 insertions(+), 27 deletions(-)
>>
>> [...]
>>
>>> diff --git a/block/raw-win32.c b/block/raw-win32.c
>>> index 56f45fe..734bb10 100644
>>> --- a/block/raw-win32.c
>>> +++ b/block/raw-win32.c
>>
>> [...]
>>
>>> +static bool get_aio_option(QemuOpts *opts, int flags, Error **errp)
>>> +{
>>> +    BlockdevAioOptions aio, aio_default;
>>> +
>>> +    aio_default = (flags & BDRV_O_NATIVE_AIO) ? BLOCKDEV_AIO_OPTIONS_NATIVE
>>> +                                              : 
>>> BLOCKDEV_AIO_OPTIONS_THREADS;
>>> +    aio = qapi_enum_parse(BlockdevAioOptions_lookup, qemu_opt_get(opts, 
>>> "aio"),
>>> +                          BLOCKDEV_AIO_OPTIONS__MAX, aio_default, errp);
>>> +
>>> +    switch (aio) {
>>> +    case BLOCKDEV_AIO_OPTIONS_NATIVE:
>>> +        return true;
>>> +    case BLOCKDEV_AIO_OPTIONS_THREADS:
>>> +        return false;
>>> +    default:
>>> +        error_setg(errp, "Invalid AIO option");
>>
>> Any reason for catching this case here but not in raw-posix?
>>
>> (Not that it really matters, though.)
> 
> Nobody will forget raw-posix when adding a new AIO mode to win32, so I
> didn't feel like the additional code was worth it there. But if we add a
> new AIO mode to raw-posix, I'm pretty sure we will forget win32.

:-)

Good point.

Max

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