[PATCH v11 06/10] io_uring: introduce attributes for read/write and PI support

[Martin K. Petersen]

Anuj,

> Add the ability to pass additional attributes along with read/write.
> Application can prepare attibute specific information and pass its
> address using the SQE field:
> 	__u64	attr_ptr;
>
> Along with setting a mask indicating attributes being passed:
> 	__u64	attr_type_mask;
>
> Overall 64 attributes are allowed and currently one attribute
> 'IORING_RW_ATTR_FLAG_PI' is supported.

I have things running on my end on top of Jens' tree (without error
injection, that's to come).

One question, though: How am I to determine that the kernel supports
attr_ptr and IORING_RW_ATTR_FLAG_PI? Now that we no longer have separate
IORING_OP_{READ,WRITE}_META commands I can't use IO_URING_OP_SUPPORTED
to find out whether the running kernel supports PI passthrough.

-- 
Martin K. Petersen	Oracle Linux Engineering