Re: [PATCH v2 01/11] dma-buf/sync_file: de-stage sync_file

From: Emil Velikov
Date: Wed Jan 27 2016 - 13:17:28 EST

Hi Gustavo,

On 27 January 2016 at 17:03, Gustavo Padovan <gustavo@xxxxxxxxxxx> wrote:
> Hi Maarten,
> 2016-01-27 Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx>:
>> Hey,
>> Op 27-01-16 om 14:30 schreef Gustavo Padovan:
>> > From: Gustavo Padovan <gustavo.padovan@xxxxxxxxxxxxxxx>
>> >
>> > sync_file is useful to connect one or more fences to the file. The file is
>> > used by userspace to track fences.
>> >
>> > Signed-off-by: Gustavo Padovan <gustavo.padovan@xxxxxxxxxxxxxxx>
>> >
>> Is there a value in keeping the abi unchanged?
>> If not, then Documentation/ioctl/botching-up-ioctls.txt is worth a read.
> None from me. I'll look where we can improve the ABI.
Speaking of ABI... there are a couple of things that rang bells here:
- In most/all of the kernel a len/size named member variable
indicates the length of the extra data (zero sized array). While here
it includes the size of the struct as well.
- struct sync_file_info_data::fence_info is of type __u8 yet it is "a
fence_info struct for every fence in the sync_file". Thus shouldn't
one use "struct fence_info" as the type ?