cac9e4418f4cb ("io_uring/net: save msghdr->msg_control for retries")
reinstatiates msg_control before every __sys_sendmsg_sock(), since the
function can overwrite the value in msghdr. We need to do same for
zerocopy sendmsg.

Cc: stable@vger.kernel.org
Fixes: 493108d95f146 ("io_uring/net: zerocopy sendmsg")
Link: https://github.com/axboe/liburing/issues/1067
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/cc1d5d9df0576fa66ddad4420d240a98a020b267.1712596179.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

If we get a request with IOSQE_ASYNC set, then we first run the prep
async handlers. But if we then fail setting it up and want to post
a CQE with -EINVAL, we use ->done_io. This was previously guarded with
REQ_F_PARTIAL_IO, and the normal setup handlers do set it up before any
potential errors, but we need to cover the async setup too.

Fixes: 9817ad85899f ("io_uring/net: remove dependency on REQ_F_PARTIAL_IO for sr->done_io")
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Pull io_uring updates from Jens Axboe:

 - Make running of task_work internal loops more fair, and unify how the
   different methods deal with them (me)

 - Support for per-ring NAPI. The two minor networking patches are in a
   shared branch with netdev (Stefan)

 - Add support for truncate (Tony)

 - Export SQPOLL utilization stats (Xiaobing)

 - Multishot fixes (Pavel)

 - Fix for a race in manipulating the request flags via poll (Pavel)

 - Cleanup the multishot checking by making it generic, moving it out of
   opcode handlers (Pavel)

 - Various tweaks and cleanups (me, Kunwu, Alexander)

* tag 'for-6.9/io_uring-20240310' of git://git.kernel.dk/linux: (53 commits)
  io_uring: Fix sqpoll utilization check racing with dying sqpoll
  io_uring/net: dedup io_recv_finish req completion
  io_uring: refactor DEFER_TASKRUN multishot checks
  io_uring: fix mshot io-wq checks
  io_uring/net: add io_req_msg_cleanup() helper
  io_uring/net: simplify msghd->msg_inq checking
  io_uring/kbuf: rename REQ_F_PARTIAL_IO to REQ_F_BL_NO_RECYCLE
  io_uring/net: remove dependency on REQ_F_PARTIAL_IO for sr->done_io
  io_uring/net: correctly handle multishot recvmsg retry setup
  io_uring/net: clear REQ_F_BL_EMPTY in the multishot retry handler
  io_uring: fix io_queue_proc modifying req->flags
  io_uring: fix mshot read defer taskrun cqe posting
  io_uring/net: fix overflow check in io_recvmsg_mshot_prep()
  io_uring/net: correct the type of variable
  io_uring/sqpoll: statistics of the true utilization of sq threads
  io_uring/net: move recv/recvmsg flags out of retry loop
  io_uring/kbuf: flag request if buffer pool is empty after buffer pick
  io_uring/net: improve the usercopy for sendmsg/recvmsg
  io_uring/net: move receive multishot out of the generic msghdr path
  io_uring/net: unify how recvmsg and sendmsg copy in the msghdr
  ...

There are two block in io_recv_finish() completing the request, which we
can combine and remove jumping.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/0e338dcb33c88de83809fda021cba9e7c9681620.1709905727.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

We disallow DEFER_TASKRUN multishots from running by io-wq, which is
checked by individual opcodes in the issue path. We can consolidate all
it in io_wq_submit_work() at the same time moving the checks out of the
hot path.

Suggested-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/e492f0f11588bb5aa11d7d24e6f53b7c7628afdb.1709905727.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

When checking for concurrent CQE posting, we're not only interested in
requests running from the poll handler but also strayed requests ended
up in normal io-wq execution. We're disallowing multishots in general
from io-wq, not only when they came in a certain way.

Cc: stable@vger.kernel.org
Fixes: 17add5cea2bba ("io_uring: force multishot CQEs into task context")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/d8c5b36a39258036f93301cd60d3cd295e40653d.1709905727.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

For the fast inline path, we manually recycle the io_async_msghdr and
free the iovec, and then clear the REQ_F_NEED_CLEANUP flag to avoid
that needing doing in the slower path. We already do that in 2 spots, and
in preparation for adding more, add a helper and use it.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

Just check for larger than zero rather than check for non-zero and
not -1. This is easier to read, and also protects against any errants
< 0 values that aren't -1.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

We only use the flag for this purpose, so rename it accordingly. This
further prevents various other use cases of it, keeping it clean and
consistent. Then we can also check it in one spot, when it's being
attempted recycled, and remove some dead code in io_kbuf_recycle_ring().

Signed-off-by: Jens Axboe <axboe@kernel.dk>

Ensure that prep handlers always initialize sr->done_io before any
potential failure conditions, and with that, we now it's always been
set even for the failure case.

With that, we don't need to use the REQ_F_PARTIAL_IO flag to gate on that.
Additionally, we should not overwrite req->cqe.res unless sr->done_io is
actually positive.

Signed-off-by: Jens Axboe <axboe@kernel.dk>