[PATCHSET v2 RFC 0/11] Add support for ring mapped provided buffers

[Jens Axboe <axboe@kernel.dk>]

Hi,

This series builds to adding support for a different way of doing
provided buffers. The interesting bits here are patch 11, which also has
some performance numbers an an explanation of it.

Patches 1..5 are cleanups that should just applied separately, I
think the clean up the existing code quite nicely.

Patch 6 is a generic optimization for the buffer list lookups.

Patch 7 adds NOP support for provided buffers, just so that we can
benchmark the last change.

Patches 8..10 are prep for patch 11.

Patch 11 finally adds the feature.

This passes the full liburing suite - obviously this just means that it
didn't break anything existing (that I know of), the only test case for
the ring buffers is the nop peak benchmark referenced in patch 11.

v2:	- Minor optimizations
	- Fix 4k PAGE_SIZE assumption
	- Style cleanup

Can also be found in my git repo, for-5.19/io_uring-pbuf branch:

https://git.kernel.dk/cgit/linux-block/log/?h=for-5.19/io_uring-pbuf

 fs/io_uring.c                 | 463 +++++++++++++++++++++++++---------
 include/uapi/linux/io_uring.h |  26 ++
 2 files changed, 370 insertions(+), 119 deletions(-)

-- 
Jens Axboe