Re: [PATCH v3 4/4] io_uring: add support for zone-append

Christoph Hellwig
2020-07-10T13:49:52Z

On Fri, Jul 10, 2020 at 02:48:24PM +0100, Matthew Wilcox wrote:
> If we're going to go the route of changing the CQE, how about:
>
> struct io_uring_cqe {
> __u64 user_data; /* sqe->data submission passed back */
> - __s32 res; /* result code for this event */
> - __u32 flags;
> + union {
> + struct {
> + __s32 res; /* result code for this event */
> + __u32 flags;
> + };
> + __s64 res64;
> + };
> };
>
> then we don't need to change the CQE size and it just depends on the SQE
> whether the CQE for it uses res+flags or res64.

How do you return a status code or short write when you just have
a u64 that is needed for the offset?