Re: [Qemu-devel] [PATCH v6 2/6] queue: Add macro for incremental traversal

[Richard Henderson <rth@twiddle.net>]

On 06/26/2017 05:33 AM, Lluís Vilanova wrote:
> Richard Henderson writes:
> 
>> On 06/12/2017 07:54 AM, Lluís Vilanova wrote:
>>> Adds macro QTAILQ_FOREACH_CONTINUE to support incremental list
>>> traversal.
>>>
>>> Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
>>> ---
>>> include/qemu/queue.h |   12 ++++++++++++
>>> 1 file changed, 12 insertions(+)
>>>
>>> diff --git a/include/qemu/queue.h b/include/qemu/queue.h
>>> index 35292c3155..eb2bf9cb1c 100644
>>> --- a/include/qemu/queue.h
>>> +++ b/include/qemu/queue.h
>>> @@ -415,6 +415,18 @@ struct {                                                                \
>>> (var);                                                  \
>>> (var) = ((var)->field.tqe_next))
>>> +/**
>>> + * QTAILQ_FOREACH_CONTINUE:
>>> + * @var: Variable to resume iteration from.
>>> + * @field: Field in @var holding a QTAILQ_ENTRY for this queue.
>>> + *
>>> + * Resumes iteration on a queue from the element in @var.
>>> + */
>>> +#define QTAILQ_FOREACH_CONTINUE(var, field)                             \
>>> +        for ((var) = ((var)->field.tqe_next);                           \
>>> +                (var);                                                  \
>>> +                (var) = ((var)->field.tqe_next))
>>> +
>>> #define QTAILQ_FOREACH_SAFE(var, head, field, next_var)                 \
>>> for ((var) = ((head)->tqh_first);                               \
>>> (var) && ((next_var) = ((var)->field.tqe_next), 1);     \
>>>
>>>
> 
>> I still say this isn't required if the breakpoint loop is better structured.
> 
> I can embed the use of QTAILQ into translate-block.c, but I wanted to keep the
> implementation of breakpoint lists hidden behind the cpu_breakpoint API.

I think using QTAILQ in the common main loop is better than twisting the logic 
so that the loop is unnaturally split into a subroutine.


r~