On Thursday 22 March 2012 15:26:08 Daniel Vetter wrote:
On Thu, Mar 22, 2012 at 03:07:18PM +0100, Laurent Pinchart wrote:
- Contains data used for exporting a video buffer as DMABUF file
- descriptor. Uses the same 'cookie' as mmap() syscall. All
reserved fields
- must be set to zero.
- */
+struct v4l2_exportbuffer {
- __u32 fd;
- __u32 reserved0;
Why is there a reserved field here ?
+1 to Laurent. Any particular need for reserved0 and reserved[13] below? I think one void user pointer is sufficient even for future need.
I'd rather have more than one void user pointer, just in case. A couple of bytes won't be expensive, and they will save lots of hassle in the future if we need to add a couple of fields. I was just wondering why there was a reserved field between fd and mem_offset.
Quick comment from a random bystander: __u32 is not big enough for a void* pointer from userspace ...
That's why I'm happy with 14 reserved __u32. That should be enough for userspace pointers in the foreseable future :-)