Move REQ_F_BUFFER_SELECT flag check out of io_recv_buffer_select(), and
do that in its call sites That saves us from double error checking and
possibly an extra function call.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_clean_op() may be skipped even if there is a selected io_buffer,
that's because *select_buffer() funcions never set REQ_F_NEED_CLEANUP.

Trigger io_clean_op() when REQ_F_BUFFER_SELECTED is set as well, and
and clear the flag if was freed out of it.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Instead of returning error from io_recv(), go through generic cleanup
path, because it'll retain cflags for userspace. Do the same for
io_send() for consistency.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

With the return on a bad socket, kmsg is always non-null by the end
of the function, prune left extra checks and initialisations.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Flip over "if (sock)" condition with return on error, the upper layer
will take care. That change will be handy later, but already removes
an extra jump from hot path.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Currently, file refs in struct io_submit_state are tracked with 2 vars:
@has_refs -- how many refs were initially taken
@used_refs -- number of refs used

Replace it with a single variable counting how many refs left at the
current moment.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

RLIMIT_SIZE in needed only for execution from an io-wq context, hence
move all preparations from hot path to io-wq work setup.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Every call to io_req_defer_prep() is prepended with allocating ->io,
just do that in the function. And while we're at it, mark error paths
with unlikey and replace "if (ret < 0)" with "if (ret)".

There is only one change in the observable behaviour, that's instead of
killing the head request right away on error, it postpones it until the
link is assembled, that looks more preferable.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

A switch in __io_clean_op() doesn't have default, it's pointless to list
opcodes that doesn't do any cleanup. Remove IORING_OP_OPEN* from there.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

The only caller of io_req_work_grab_env() is io_prep_async_work(), and
they are both initialising req->work. Inline grab_env(), it's easier
to keep this way, moreover there already were bugs with misplacing
io_req_init_async().
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

req->cflags is used only for defer-completion path, just use completion
data to store it. With the 4 bytes from the ->sequence patch and
compacting io_kiocb, this frees 8 bytes.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

req->sequence is used only for deferred (i.e. DRAIN) requests, but
initialised for every request. Remove req->sequence from io_kiocb
together with its initialisation in io_init_req().

Replace it with a new field in struct io_defer_entry, that will be
calculated only when needed in io_req_defer(), which is a slow path.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

The only left user of req->list is DRAIN, hence instead of keeping a
separate per request list for it, do that with old fashion non-intrusive
lists allocated on demand. That's a really slow path, so that's OK.

This removes req->list and so sheds 16 bytes from io_kiocb.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

poll*() doesn't use req->list, don't init it.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Instead of using shared req->list, hang timeouts up on their own list
entry. struct io_timeout have enough extra space for it, but if that
will be a problem ->inflight_entry can reused for that.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

As with the completion path, also use compl.list for overflowed
requests. If cleaned up properly, nobody needs per-op data there
anymore.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

req->inflight_entry is used to track requests that grabbed files_struct.
Let's share it with iopoll list, because the only iopoll'ed ops are
reads and writes, which don't need a file table.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

It supports both polling and I/O polling. Rename ctx->poll to clearly
show that it's only in I/O poll case.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Calling io_req_complete(req) means that the request is done, and there
is nothing left but to clean it up. That also means that per-op data
after that should not be used, so we're free to reuse it in completion
path, e.g. to store overflow_list as done in this patch.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

As for import_iovec(), return !=NULL iovec from io_import_iovec() only
when it should be freed. That includes returning NULL when iovec is
already in req->io, because it should be deallocated by other means,
e.g. inside op handler. After io_setup_async_rw() local iovec to ->io,
just mark it NULL, to follow the idea in io_{read,write} as well.

That's easier to follow, and especially useful if we want to reuse
per-op space for completion data.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
[axboe: only call kfree() on non-NULL pointer]
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Preparing reads/writes for async is a bit tricky. Extract a helper to
not repeat it twice.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Don't deref req->io->rw every time, but put it in a local variable. This
looks prettier, generates less instructions, and doesn't break alias
analysis.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_kiocb::task_work was de-unionised, and is not planned to be shared
back, because it's too useful and commonly used. Hence, instead of
keeping a separate task_work in struct io_async_rw just reuse
req->task_work.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Don't repeat send msg initialisation code, it's error prone.
Extract and use a helper function.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

send/recv msghdr initialisation works with struct io_async_msghdr, but
pulls the whole struct io_async_ctx for no reason. That complicates it
with composite accessing, e.g. io->msg.

Use and pass the most specific type, which is struct io_async_msghdr.
It is the larget field in union io_async_ctx and doesn't save stack
space, but looks clearer.
The most of the changes are replacing "io->msg." with "iomsg->"
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Every second field in send/recv is called msg, make it a bit more
understandable by renaming ->msg, which is a user provided ptr,
to ->umsg.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

rings_size() sets sq_offset to the total size of the rings (the returned
value which is used for memory allocation). This is wrong: sq array should
be located within the rings, not after them. Set sq_offset to where it
should be.

Fixes: 75b28aff ("io_uring: allocate the two rings together")
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Acked-by: Hristo Venev <hristo@venev.name>
Cc: io-uring@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Merge in io_uring-5.8 fixes, as changes/cleanups to how we do locked
mem accounting require a fixup, and only one of the spots are noticed
by git as the other merges cleanly. The flags fix from io_uring-5.8
also causes a merge conflict, the leak fix for recvmsg, the double poll
fix, and the link failure locking fix.

* io_uring-5.8:
  io_uring: fix lockup in io_fail_links()
  io_uring: fix ->work corruption with poll_add
  io_uring: missed req_init_async() for IOSQE_ASYNC
  io_uring: always allow drain/link/hardlink/async sqe flags
  io_uring: ensure double poll additions work with both request types
  io_uring: fix recvmsg memory leak with buffer selection
  io_uring: fix not initialised work->flags
  io_uring: fix missing msg_name assignment
  io_uring: account user memory freed when exit has been queued
  io_uring: fix memleak in io_sqe_files_register()
  io_uring: fix memleak in __io_sqe_files_update()
  io_uring: export cq overflow status to userspace
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_fail_links() doesn't consider REQ_F_COMP_LOCKED leading to nested
spin_lock(completion_lock) and lockup.

[  197.680409] rcu: INFO: rcu_preempt detected expedited stalls on
	CPUs/tasks: { 6-... } 18239 jiffies s: 1421 root: 0x40/.
[  197.680411] rcu: blocking rcu_node structures:
[  197.680412] Task dump for CPU 6:
[  197.680413] link-timeout    R  running task        0  1669
	1 0x8000008a
[  197.680414] Call Trace:
[  197.680420]  ? io_req_find_next+0xa0/0x200
[  197.680422]  ? io_put_req_find_next+0x2a/0x50
[  197.680423]  ? io_poll_task_func+0xcf/0x140
[  197.680425]  ? task_work_run+0x67/0xa0
[  197.680426]  ? do_exit+0x35d/0xb70
[  197.680429]  ? syscall_trace_enter+0x187/0x2c0
[  197.680430]  ? do_group_exit+0x43/0xa0
[  197.680448]  ? __x64_sys_exit_group+0x18/0x20
[  197.680450]  ? do_syscall_64+0x52/0xa0
[  197.680452]  ? entry_SYSCALL_64_after_hwframe+0x44/0xa9
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

req->work might be already initialised by the time it gets into
__io_arm_poll_handler(), which will corrupt it by using fields that are
in an union with req->work. Luckily, the only side effect is missing
put_creds(). Clean req->work before going there.
Suggested-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

IOSQE_ASYNC branch of io_queue_sqe() is another place where an
unitialised req->work can be accessed (i.e. prior io_req_init_async()).
Nothing really bad though, it just looses IO_WQ_WORK_CONCURRENT flag.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

We currently filter these for timeout_remove/async_cancel/files_update,
but we only should be filtering for fixed file and buffer select. This
also causes a second read of sqe->flags, which isn't needed.

Just check req->flags for the relevant bits. This then allows these
commands to be used in links, for example, like everything else.
Signed-off-by: Daniele Albano <d.albano@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

The double poll additions were centered around doing POLL_ADD on file
descriptors that use more than one waitqueue (typically one for read,
one for write) when being polled. However, it can also end up being
triggered for when we use poll triggered retry. For that case, we cannot
safely use req->io, as that could be used by the request type itself.

Add a second io_poll_iocb pointer in the structure we allocate for poll
based retry, and ensure we use the right one from the two paths.

Fixes: 18bceab1 ("io_uring: allow POLL_ADD with double poll_wait() users")
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_recvmsg() doesn't free memory allocated for struct io_buffer. This can
causes a leak when used with automatic buffer selection.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

59960b9d ("io_uring: fix lazy work init") tried to fix missing
io_req_init_async(), but left out work.flags and hash. Do it earlier.

Fixes: 7cdaf587 ("io_uring: avoid whole io_wq_work copy for requests completed inline")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Ensure to set msg.msg_name for the async portion of send/recvmsg,
as the header copy will copy to/from it.

Cc: stable@vger.kernel.org # v5.5+
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

We currently account the memory after the exit work has been run, but
that leaves a gap where a process has closed its ring and until the
memory has been accounted as freed. If the memlocked ulimit is
borderline, then that can introduce spurious setup errors returning
-ENOMEM because the free work hasn't been run yet.

Account this as freed when we close the ring, as not to expose a tiny
gap where setting up a new ring can fail.

Fixes: 85faa7b8 ("io_uring: punt final io_ring_ctx wait-and-free to workqueue")
Cc: stable@vger.kernel.org # v5.7
Signed-off-by: Jens Axboe <axboe@kernel.dk>

I got a memleak report when doing some fuzz test:

BUG: memory leak
unreferenced object 0x607eeac06e78 (size 8):
  comm "test", pid 295, jiffies 4294735835 (age 31.745s)
  hex dump (first 8 bytes):
    00 00 00 00 00 00 00 00                          ........
  backtrace:
    [<00000000932632e6>] percpu_ref_init+0x2a/0x1b0
    [<0000000092ddb796>] __io_uring_register+0x111d/0x22a0
    [<00000000eadd6c77>] __x64_sys_io_uring_register+0x17b/0x480
    [<00000000591b89a6>] do_syscall_64+0x56/0xa0
    [<00000000864a281d>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

Call percpu_ref_exit() on error path to avoid
refcount memleak.

Fixes: 05f3fb3c ("io_uring: avoid ring quiesce for fixed file set unregister and update")
Cc: stable@vger.kernel.org
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

We don't use 'ctx' at all in io_sq_thread_drop_mm(), it just works
on the mm of the current task. Drop the argument.

Move io_file_put_work() to where we have the other forward declarations
of functions.
Signed-off-by: Jens Axboe <axboe@kernel.dk>

We just have one caller of this, req_need_defer(), just inline the
code in there instead.
Signed-off-by: Jens Axboe <axboe@kernel.dk>