[Mesa-dev] [PATCH 1/2] util: Fix foreach_list_typed_safe when exec_node is not at offset 0.

[Matt Turner]

On Mon, Mar 9, 2015 at 7:24 PM, Matt Turner <mattst88 at gmail.com> wrote:
> On Mon, Mar 9, 2015 at 6:36 PM, Kenneth Graunke <kenneth at whitecape.org> wrote:
>> From: Jason Ekstrand <jason.ekstrand at intel.com>
>>
>> __next and __prev are pointers to the structure containing the exec_node
>> link, not the embedded exec_node.  NULL checks would fail unless the
>> embedded exec_node happened to be at offset 0 in the parent struct.
>>
>> Signed-off-by: Jason Ekstrand <jason.ekstrand at intel.com>
>> Reviewed-by: Kenneth Graunke <kenneth at whitecape.org>
>> ---
>>  src/glsl/list.h | 4 ++--
>>  1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/src/glsl/list.h b/src/glsl/list.h
>> index ddb98f7..680e963 100644
>> --- a/src/glsl/list.h
>> +++ b/src/glsl/list.h
>> @@ -684,7 +684,7 @@ inline void exec_node::insert_before(exec_list *before)
>>             exec_node_data(__type, (__list)->head, __field),                \
>>                 * __next =                                                  \
>>             exec_node_data(__type, (__node)->__field.next, __field);        \
>> -        __next != NULL;                                                    \
>> +        &__next->__field != NULL;                                          \
>
> I'm not understanding now the address of __next->__field can ever be NULL.
>
> __next is something with an embedded struct exec_node, so don't we
> want "__next->__field != NULL" without the address-of operator?

Sorry, that should have been "exec_node_is_tail_sentinel(&__next->__field)"