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Date: Tue, 06 Jan 2015 10:39:13 +0800
From: "Chen, Tiejun" <tiejun.chen@intel.com>
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Subject: Re: [Qemu-devel] [RFC][PATCH] qemu_opt_get_bool_helper: back
 finding desc by name just if !opt->desc
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To: Eric Blake <eblake@redhat.com>, marcel.a@redhat.com, peter.maydell@linaro.org, agraf@suse.de, greg.bellows@linaro.org
Cc: qemu-devel@nongnu.org

On 2015/1/6 9:21, Chen, Tiejun wrote:
> On 2015/1/6 1:13, Eric Blake wrote:
>> On 01/04/2015 10:35 PM, Tiejun Chen wrote:
>>> After one commit 49d2e648e808, "machine: remove qemu_machine_opts
>>> global list", is introduced, QEMU doesn't keep a global list of
>>> options but set desc lately. Then we can see the following,
>>>
>>> $ x86_64-softmmu/qemu-system-x86_64 -usb
>>> qemu-system-x86_64: util/qemu-option.c:387: qemu_opt_get_bool_helper: \
>>>      Assertion `opt->desc && opt->desc->type == QEMU_OPT_BOOL' failed.
>>> Aborted (core dumped)
>>>
>>> So inside qemu_opt_get_bool_helper, we need to call find_desc_by_name()
>>> to work parse_option_bool() out just in case of !opt->desc.
>>>
>>> Signed-off-by: Tiejun Chen <tiejun.chen@intel.com>
>>> ---
>>>   util/qemu-option.c | 2 +-
>>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/util/qemu-option.c b/util/qemu-option.c
>>> index a708241..7cb3601 100644
>>> --- a/util/qemu-option.c
>>> +++ b/util/qemu-option.c
>>> @@ -377,7 +377,7 @@ static bool qemu_opt_get_bool_helper(QemuOpts
>>> *opts, const char *name,
>>>       }
>>>
>>>       opt = qemu_opt_find(opts, name);
>>> -    if (opt == NULL) {
>>> +    if ((opt == NULL) || !opt->desc)  {
>>
>> Over-parenthesized, and looks like you also introduced a spurious space.
>>   Simpler to just have:
>>
>> if (!opt || !opt->desc) {
>
> Looks good.
>
>>
>> Also, there are other threads about the same topic.
>> https://lists.gnu.org/archive/html/qemu-devel/2015-01/msg00130.html
>
> Yeah, I already notice that.
>

Then I realize I need to extend this to all qemu_opt_get_*.

Tiejun