[Qemu-devel] Re: [PATCH 1/2] Add TAILQ_FOREACH_SAFE

[Jan Kiszka <jan.kiszka@siemens.com>]

Jamie Lokier wrote:
> Anthony Liguori wrote:
>> Wouldn't:
>>
>> (var) ? ({ (next_var) = ((var)->field.tqe_next); 1;}) :0;
>>
>> Be equivalent to:
>>
>> (var) ? ((next_var = ((var)->field.tqe_next), var) : var
> 
> Simpler:
> 
> (var) && ((next_var) = (var)->field.tqe_next, 1)
> 

Yes, indeed!

Anthony, could you merge this one and its application patch? I need both
of them for my kvm series.

Jan

-------------->

Add TAILQ iterator that allows to safely remove elements while walking
the list.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
---

 sys-queue.h |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/sys-queue.h b/sys-queue.h
index 3d0773e..ad5c8fb 100644
--- a/sys-queue.h
+++ b/sys-queue.h
@@ -210,6 +210,11 @@ struct {                                                                \
                 (var);                                                  \

                 (var) = ((var)->field.tqe_next))

 

+#define TAILQ_FOREACH_SAFE(var, head, field, next_var)                  \

+        for ((var) = ((head)->tqh_first);                               \

+                (var) && ((next_var) = ((var)->field.tqe_next), 1);     \

+                (var) = (next_var))

+

 #define TAILQ_FOREACH_REVERSE(var, head, headname, field)               \

         for ((var) = (*(((struct headname *)((head)->tqh_last))->tqh_last));    \

                 (var);                                                  \