Commit Graph

365 Commits

Author SHA1 Message Date
Jens Axboe 0b5faf6ba7 io_uring: allow AT_FDCWD for non-file openat/openat2/statx
Don't just check for dirfd == -1, we should allow AT_FDCWD as well for
relative lookups.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-08 13:07:00 -07:00
Jens Axboe ff002b3018 io_uring: grab ->fs as part of async preparation
This passes it in to io-wq, so it assumes the right fs_struct when
executing async work that may need to do lookups.

Cc: stable@vger.kernel.org # 5.3+
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-08 13:07:00 -07:00
Jens Axboe faac996ccd io_uring: retry raw bdev writes if we hit -EOPNOTSUPP
For non-blocking issue, we set IOCB_NOWAIT in the kiocb. However, on a
raw block device, this yields an -EOPNOTSUPP return, as non-blocking
writes aren't supported. Turn this -EOPNOTSUPP into -EAGAIN, so we retry
from blocking context with IOCB_NOWAIT cleared.

Cc: stable@vger.kernel.org # 5.5
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-08 13:06:58 -07:00
Pavel Begunkov 8fef80bf56 io_uring: add cleanup for openat()/statx()
openat() and statx() may have allocated ->open.filename, which should be
be put. Add cleanup handlers for them.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-08 13:06:58 -07:00
Pavel Begunkov 99bc4c3853 io_uring: fix iovec leaks
Allocated iovec is freed only in io_{read,write,send,recv)(), and just
leaves it if an error occured. There are plenty of such cases:
- cancellation of non-head requests
- fail grabbing files in __io_queue_sqe()
- set REQ_F_NOWAIT and returning in __io_queue_sqe()

Add REQ_F_NEED_CLEANUP, which will force such requests with custom
allocated resourses go through cleanup handlers on put.

Cc: stable@vger.kernel.org # 5.5
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-08 13:06:58 -07:00
Pavel Begunkov e96e977992 io_uring: remove unused struct io_async_open
struct io_async_open is unused, remove it.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-08 13:06:58 -07:00
Stefano Garzarella 63e5d81f72 io_uring: flush overflowed CQ events in the io_uring_poll()
In io_uring_poll() we must flush overflowed CQ events before to
check if there are CQ events available, to avoid missing events.

We call the io_cqring_events() that checks and flushes any overflow
and returns the number of CQ events available.

Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-08 13:06:58 -07:00
Jens Axboe cf3040ca55 io_uring: statx/openat/openat2 don't support fixed files
All of these opcodes take a directory file descriptor. We can't easily
support fixed files for these operations, and the use case for that
probably isn't all that clear (or sensible) anyway.

Disable IOSQE_FIXED_FILE for these operations.

Reported-by: Stefan Metzmacher <metze@samba.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-08 13:06:33 -07:00
Pavel Begunkov 1e95081cb5 io_uring: fix deferred req iovec leak
After defer, a request will be prepared, that includes allocating iovec
if needed, and then submitted through io_wq_submit_work() but not custom
handler (e.g. io_rw_async()/io_sendrecv_async()). However, it'll leak
iovec, as it's in io-wq and the code goes as follows:

io_read() {
	if (!io_wq_current_is_worker())
		kfree(iovec);
}

Put all deallocation logic in io_{read,write,send,recv}(), which will
leave the memory, if going async with -EAGAIN.

It also fixes a leak after failed io_alloc_async_ctx() in
io_{recv,send}_msg().

Cc: stable@vger.kernel.org # 5.5
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-06 13:58:57 -07:00
Randy Dunlap e1d85334d6 io_uring: fix 1-bit bitfields to be unsigned
Make bitfields of size 1 bit be unsigned (since there is no room
for the sign bit).
This clears up the sparse warnings:

  CHECK   ../fs/io_uring.c
../fs/io_uring.c:207:50: error: dubious one-bit signed bitfield
../fs/io_uring.c:208:55: error: dubious one-bit signed bitfield
../fs/io_uring.c:209:63: error: dubious one-bit signed bitfield
../fs/io_uring.c:210:54: error: dubious one-bit signed bitfield
../fs/io_uring.c:211:57: error: dubious one-bit signed bitfield

Found by sight and then verified with sparse.

Fixes: 69b3e54613 ("io_uring: change io_ring_ctx bool fields into bit fields")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: io-uring@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-06 13:41:00 -07:00
Pavel Begunkov 1cb1edb2f5 io_uring: get rid of delayed mm check
Fail fast if can't grab mm, so past that requests always have an mm
when required. This allows us to remove req->user altogether.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-06 12:53:10 -07:00
Linus Torvalds c1ef57a3a3 io_uring-5.6-2020-02-05
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Merge tag 'io_uring-5.6-2020-02-05' of git://git.kernel.dk/linux-block

Pull io_uring updates from Jens Axboe:
 "Some later fixes for io_uring:

   - Small cleanup series from Pavel

   - Belt and suspenders build time check of sqe size and layout
     (Stefan)

   - Addition of ->show_fdinfo() on request of Jann Horn, to aid in
     understanding mapped personalities

   - eventfd recursion/deadlock fix, for both io_uring and aio

   - Fixup for send/recv handling

   - Fixup for double deferral of read/write request

   - Fix for potential double completion event for close request

   - Adjust fadvise advice async/inline behavior

   - Fix for shutdown hang with SQPOLL thread

   - Fix for potential use-after-free of fixed file table"

* tag 'io_uring-5.6-2020-02-05' of git://git.kernel.dk/linux-block:
  io_uring: cleanup fixed file data table references
  io_uring: spin for sq thread to idle on shutdown
  aio: prevent potential eventfd recursion on poll
  io_uring: put the flag changing code in the same spot
  io_uring: iterate req cache backwards
  io_uring: punt even fadvise() WILLNEED to async context
  io_uring: fix sporadic double CQE entry for close
  io_uring: remove extra ->file check
  io_uring: don't map read/write iovec potentially twice
  io_uring: use the proper helpers for io_send/recv
  io_uring: prevent potential eventfd recursion on poll
  eventfd: track eventfd_signal() recursion depth
  io_uring: add BUILD_BUG_ON() to assert the layout of struct io_uring_sqe
  io_uring: add ->show_fdinfo() for the io_uring file descriptor
2020-02-06 06:33:17 +00:00
Jens Axboe 2faf852d1b io_uring: cleanup fixed file data table references
syzbot reports a use-after-free in io_ring_file_ref_switch() when it
tries to switch back to percpu mode. When we put the final reference to
the table by calling percpu_ref_kill_and_confirm(), we don't want the
zero reference to queue async work for flushing the potentially queued
up items. We currently do a few flush_work(), but they merely paper
around the issue, since the work item may not have been queued yet
depending on the when the percpu-ref callback gets run.

Coming into the file unregister, we know we have the ring quiesced.
io_ring_file_ref_switch() can check for whether or not the ref is dying
or not, and not queue anything async at that point. Once the ref has
been confirmed killed, flush any potential items manually.

Reported-by: syzbot+7caeaea49c2c8a591e3d@syzkaller.appspotmail.com
Fixes: 05f3fb3c53 ("io_uring: avoid ring quiesce for fixed file set unregister and update")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-04 20:04:18 -07:00
Jens Axboe df069d80c8 io_uring: spin for sq thread to idle on shutdown
As part of io_uring shutdown, we cancel work that is pending and won't
necessarily complete on its own. That includes requests like poll
commands and timeouts.

If we're using SQPOLL for kernel side submission and we shutdown the
ring immediately after queueing such work, we can race with the sqthread
doing the submission. This means we may miss cancelling some work, which
results in the io_uring shutdown hanging forever.

Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-04 16:48:34 -07:00
Pavel Begunkov 3e577dcd73 io_uring: put the flag changing code in the same spot
Both iocb_flags() and kiocb_set_rw_flags() are inline and modify
kiocb->ki_flags. Place them close, so they can be potentially better
optimised.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-03 17:27:47 -07:00
Pavel Begunkov 6c8a313469 io_uring: iterate req cache backwards
Grab requests from cache-array from the end, so can get by only
free_reqs.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-03 17:27:47 -07:00
Jens Axboe 3e69426da2 io_uring: punt even fadvise() WILLNEED to async context
Andres correctly points out that read-ahead can block, if it needs to
read in meta data (or even just through the page cache page allocations).
Play it safe for now and just ensure WILLNEED is also punted to async
context.

While in there, allow the file settings hints from non-blocking
context. They don't need to start/do IO, and we can safely do them
inline.

Fixes: 4840e418c2 ("io_uring: add IORING_OP_FADVISE")
Reported-by: Andres Freund <andres@anarazel.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-03 17:27:47 -07:00
Jens Axboe 1a417f4e61 io_uring: fix sporadic double CQE entry for close
We punt close to async for the final fput(), but we log the completion
even before that even in that case. We rely on the request not having
a files table assigned to detect what the final async close should do.
However, if we punt the async queue to __io_queue_sqe(), we'll get
->files assigned and this makes io_close_finish() think it should both
close the filp again (which does no harm) AND log a new CQE event for
this request. This causes duplicate CQEs.

Queue the request up for async manually so we don't grab files
needlessly and trigger this condition.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-03 17:27:47 -07:00
Pavel Begunkov 9250f9ee19 io_uring: remove extra ->file check
It won't ever get into io_prep_rw() when req->file haven't been set in
io_req_set_file(), hence remove the check.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-03 17:27:47 -07:00
Jens Axboe 5d204bcfa0 io_uring: don't map read/write iovec potentially twice
If we have a read/write that is deferred, we already setup the async IO
context for that request, and mapped it. When we later try and execute
the request and we get -EAGAIN, we don't want to attempt to re-map it.
If we do, we end up with garbage in the iovec, which typically leads
to an -EFAULT or -EINVAL completion.

Cc: stable@vger.kernel.org # 5.5
Reported-by: Dan Melnic <dmm@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-03 17:27:47 -07:00
Jens Axboe 0b7b21e42b io_uring: use the proper helpers for io_send/recv
Don't use the recvmsg/sendmsg helpers, use the same helpers that the
recv(2) and send(2) system calls use.

Reported-by: 李通洲 <carter.li@eoitek.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-03 17:27:47 -07:00
Jens Axboe f0b493e6b9 io_uring: prevent potential eventfd recursion on poll
If we have nested or circular eventfd wakeups, then we can deadlock if
we run them inline from our poll waitqueue wakeup handler. It's also
possible to have very long chains of notifications, to the extent where
we could risk blowing the stack.

Check the eventfd recursion count before calling eventfd_signal(). If
it's non-zero, then punt the signaling to async context. This is always
safe, as it takes us out-of-line in terms of stack and locking context.

Cc: stable@vger.kernel.org # 5.1+
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-03 17:27:47 -07:00
John Hubbard f1f6a7dd9b mm, tree-wide: rename put_user_page*() to unpin_user_page*()
In order to provide a clearer, more symmetric API for pinning and
unpinning DMA pages.  This way, pin_user_pages*() calls match up with
unpin_user_pages*() calls, and the API is a lot closer to being
self-explanatory.

Link: http://lkml.kernel.org/r/20200107224558.2362728-23-jhubbard@nvidia.com
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Björn Töpel <bjorn.topel@intel.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jason Gunthorpe <jgg@mellanox.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Leon Romanovsky <leonro@mellanox.com>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-01-31 10:30:38 -08:00
John Hubbard 2113b05d03 fs/io_uring: set FOLL_PIN via pin_user_pages()
Convert fs/io_uring to use the new pin_user_pages() call, which sets
FOLL_PIN.  Setting FOLL_PIN is now required for code that requires
tracking of pinned pages, and therefore for any code that calls
put_user_page().

In partial anticipation of this work, the io_uring code was already
calling put_user_page() instead of put_page().  Therefore, in order to
convert from the get_user_pages()/put_page() model, to the
pin_user_pages()/put_user_page() model, the only change required here is
to change get_user_pages() to pin_user_pages().

Link: http://lkml.kernel.org/r/20200107224558.2362728-17-jhubbard@nvidia.com
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Björn Töpel <bjorn.topel@intel.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jason Gunthorpe <jgg@mellanox.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Leon Romanovsky <leonro@mellanox.com>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-01-31 10:30:37 -08:00
Stefan Metzmacher d7f62e825f io_uring: add BUILD_BUG_ON() to assert the layout of struct io_uring_sqe
With nesting of anonymous unions and structs it's hard to
review layout changes. It's better to ask the compiler
for these things.

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-01-30 12:40:37 -07:00
Jens Axboe 87ce955b24 io_uring: add ->show_fdinfo() for the io_uring file descriptor
It can be hard to know exactly what is registered with the ring.
Especially for credentials, it'd be handy to be able to see which
ones are registered, what personalities they have, and what the ID
of each of them is.

This adds support for showing information registered in the ring from
the fdinfo of the io_uring fd. Here's an example from a test case that
registers 4 files (two of them sparse), 4 buffers, and 2 personalities:

pos:	0
flags:	02000002
mnt_id:	14
UserFiles:	4
    0: file-no-1
    1: file-no-2
    2: <none>
    3: <none>
UserBufs:	4
    0: 0x563817c46000/128
    1: 0x563817c47000/256
    2: 0x563817c48000/512
    3: 0x563817c49000/1024
Personalities:
    1
	Uid:	0		0		0		0
	Gid:	0		0		0		0
	Groups:	0
	CapEff:	0000003fffffffff
    2
	Uid:	0		0		0		0
	Gid:	0		0		0		0
	Groups:	0
	CapEff:	0000003fffffffff

Suggested-by: Jann Horn <jannh@google.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-01-30 12:40:35 -07:00
Linus Torvalds 896f8d23d0 for-5.6/io_uring-vfs-2020-01-29
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Merge tag 'for-5.6/io_uring-vfs-2020-01-29' of git://git.kernel.dk/linux-block

Pull io_uring updates from Jens Axboe:

 - Support for various new opcodes (fallocate, openat, close, statx,
   fadvise, madvise, openat2, non-vectored read/write, send/recv, and
   epoll_ctl)

 - Faster ring quiesce for fileset updates

 - Optimizations for overflow condition checking

 - Support for max-sized clamping

 - Support for probing what opcodes are supported

 - Support for io-wq backend sharing between "sibling" rings

 - Support for registering personalities

 - Lots of little fixes and improvements

* tag 'for-5.6/io_uring-vfs-2020-01-29' of git://git.kernel.dk/linux-block: (64 commits)
  io_uring: add support for epoll_ctl(2)
  eventpoll: support non-blocking do_epoll_ctl() calls
  eventpoll: abstract out epoll_ctl() handler
  io_uring: fix linked command file table usage
  io_uring: support using a registered personality for commands
  io_uring: allow registering credentials
  io_uring: add io-wq workqueue sharing
  io-wq: allow grabbing existing io-wq
  io_uring/io-wq: don't use static creds/mm assignments
  io-wq: make the io_wq ref counted
  io_uring: fix refcounting with batched allocations at OOM
  io_uring: add comment for drain_next
  io_uring: don't attempt to copy iovec for READ/WRITE
  io_uring: honor IOSQE_ASYNC for linked reqs
  io_uring: prep req when do IOSQE_ASYNC
  io_uring: use labeled array init in io_op_defs
  io_uring: optimise sqe-to-req flags translation
  io_uring: remove REQ_F_IO_DRAINED
  io_uring: file switch work needs to get flushed on exit
  io_uring: hide uring_fd in ctx
  ...
2020-01-29 18:53:37 -08:00
Jens Axboe 3e4827b05d io_uring: add support for epoll_ctl(2)
This adds IORING_OP_EPOLL_CTL, which can perform the same work as the
epoll_ctl(2) system call.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-01-29 15:46:09 -07:00
Jens Axboe f86cd20c94 io_uring: fix linked command file table usage
We're not consistent in how the file table is grabbed and assigned if we
have a command linked that requires the use of it.

Add ->file_table to the io_op_defs[] array, and use that to determine
when to grab the table instead of having the handlers set it if they
need to defer. This also means we can kill the IO_WQ_WORK_NEEDS_FILES
flag. We always initialize work->files, so io-wq can just check for
that.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-01-29 13:46:44 -07:00
Jens Axboe 75c6a03904 io_uring: support using a registered personality for commands
For personalities previously registered via IORING_REGISTER_PERSONALITY,
allow any command to select them. This is done through setting
sqe->personality to the id returned from registration, and then flagging
sqe->flags with IOSQE_PERSONALITY.

Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-01-28 17:45:31 -07:00
Jens Axboe 071698e13a io_uring: allow registering credentials
If an application wants to use a ring with different kinds of
credentials, it can register them upfront. We don't lookup credentials,
the credentials of the task calling IORING_REGISTER_PERSONALITY is used.

An 'id' is returned for the application to use in subsequent personality
support.

Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-01-28 17:44:44 -07:00
Pavel Begunkov 24369c2e3b io_uring: add io-wq workqueue sharing
If IORING_SETUP_ATTACH_WQ is set, it expects wq_fd in io_uring_params to
be a valid io_uring fd io-wq of which will be shared with the newly
created io_uring instance. If the flag is set but it can't share io-wq,
it fails.

This allows creation of "sibling" io_urings, where we prefer to keep the
SQ/CQ private, but want to share the async backend to minimize the amount
of overhead associated with having multiple rings that belong to the same
backend.

Reported-by: Jens Axboe <axboe@kernel.dk>
Reported-by: Daurnimator <quae@daurnimator.com>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-01-28 17:44:41 -07:00
Jens Axboe cccf0ee834 io_uring/io-wq: don't use static creds/mm assignments
We currently setup the io_wq with a static set of mm and creds. Even for
a single-use io-wq per io_uring, this is suboptimal as we have may have
multiple enters of the ring. For sharing the io-wq backend, it doesn't
work at all.

Switch to passing in the creds and mm when the work item is setup. This
means that async work is no longer deferred to the io_uring mm and creds,
it is done with the current mm and creds.

Flag this behavior with IORING_FEAT_CUR_PERSONALITY, so applications know
they can rely on the current personality (mm and creds) being the same
for direct issue and async issue.

Reviewed-by: Stefan Metzmacher <metze@samba.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-01-28 17:44:20 -07:00
Pavel Begunkov 9466f43741 io_uring: fix refcounting with batched allocations at OOM
In case of out of memory the second argument of percpu_ref_put_many() in
io_submit_sqes() may evaluate into "nr - (-EAGAIN)", that is clearly
wrong.

Fixes: 2b85edfc0c ("io_uring: batch getting pcpu references")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-01-27 15:36:30 -07:00
Pavel Begunkov 8cdf2193a3 io_uring: add comment for drain_next
Draining the middle of a link is tricky, so leave a comment there

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-01-27 15:36:30 -07:00
Jens Axboe 980ad26304 io_uring: don't attempt to copy iovec for READ/WRITE
For the non-vectored variant of READV/WRITEV, we don't need to setup an
async io context, and we flag that appropriately in the io_op_defs
array. However, in fixing this for the 5.5 kernel in commit 74566df3a7
we didn't have these opcodes, so the check there was added just for the
READ_FIXED and WRITE_FIXED opcodes. Replace that check with just a
single check for needing async context, that covers all four of these
read/write variants that don't use an iovec.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-01-27 15:36:29 -07:00
Jens Axboe ebe1002621 io_uring: don't cancel all work on process exit
If we're sharing the ring across forks, then one process exiting means
that we cancel ALL work and prevent future work. This is overly
restrictive. As long as we cancel the work associated with the files
from the current task, it's safe to let others persist. Normal fd close
on exit will still wait (and cancel) pending work.

Fixes: fcb323cc53 ("io_uring: io_uring: add support for async work inheriting files")
Reported-by: Andres Freund <andres@anarazel.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-01-26 10:17:12 -07:00
Jens Axboe 73e08e711d Revert "io_uring: only allow submit from owning task"
This ends up being too restrictive for tasks that willingly fork and
share the ring between forks. Andres reports that this breaks his
postgresql work. Since we're close to 5.5 release, revert this change
for now.

Cc: stable@vger.kernel.org
Fixes: 44d282796f ("io_uring: only allow submit from owning task")
Reported-by: Andres Freund <andres@anarazel.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-01-26 09:56:05 -07:00
Pavel Begunkov 86a761f81e io_uring: honor IOSQE_ASYNC for linked reqs
REQ_F_FORCE_ASYNC is checked only for the head of a link. Fix it.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-01-22 13:57:48 -07:00
Pavel Begunkov 1118591ab8 io_uring: prep req when do IOSQE_ASYNC
Whenever IOSQE_ASYNC is set, requests will be punted to async without
getting into io_issue_req() and without proper preparation done (e.g.
io_req_defer_prep()). Hence they will be left uninitialised.

Prepare them before punting.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-01-22 13:57:46 -07:00
Pavel Begunkov 0463b6c58e io_uring: use labeled array init in io_op_defs
Don't rely on implicit ordering of IORING_OP_ and explicitly place them
at a right place in io_op_defs. Now former comments are now a part of
the code and won't ever outdate.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-01-20 17:04:07 -07:00
Pavel Begunkov 6b47ee6eca io_uring: optimise sqe-to-req flags translation
For each IOSQE_* flag there is a corresponding REQ_F_* flag. And there
is a repetitive pattern of their translation:
e.g. if (sqe->flags & SQE_FLAG*) req->flags |= REQ_F_FLAG*

Use same numeric values/bits for them and copy instead of manual
handling.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-01-20 17:04:07 -07:00
Pavel Begunkov 87987898a1 io_uring: remove REQ_F_IO_DRAINED
A request can get into the defer list only once, there is no need for
marking it as drained, so remove it. This probably was left after
extracting __need_defer() for use in timeouts.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-01-20 17:04:07 -07:00
Jens Axboe e46a7950d3 io_uring: file switch work needs to get flushed on exit
We currently flush early, but if we have something in progress and a
new switch is scheduled, we need to ensure to flush after our teardown
as well.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-01-20 17:04:07 -07:00
Pavel Begunkov b14cca0c84 io_uring: hide uring_fd in ctx
req->ring_fd and req->ring_file are used only during the prep stage
during submission, which is is protected by mutex. There is no need
to store them per-request, place them in ctx.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-01-20 17:04:06 -07:00
Pavel Begunkov 0791015837 io_uring: remove extra check in __io_commit_cqring
__io_commit_cqring() is almost always called when there is a change in
the rings, so the check is rather pessimising.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-01-20 17:04:06 -07:00
Pavel Begunkov 711be0312d io_uring: optimise use of ctx->drain_next
Move setting ctx->drain_next to the only place it could be set, when it
got linked non-head requests. The same for checking it, it's interesting
only for a head of a link or a non-linked request.

No functional changes here. This removes some code from the common path
and also removes REQ_F_DRAIN_LINK flag, as it doesn't need it anymore.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-01-20 17:04:06 -07:00
Jens Axboe 66f4af93da io_uring: add support for probing opcodes
The application currently has no way of knowing if a given opcode is
supported or not without having to try and issue one and see if we get
-EINVAL or not. And even this approach is fraught with peril, as maybe
we're getting -EINVAL due to some fields being missing, or maybe it's
just not that easy to issue that particular command without doing some
other leg work in terms of setup first.

This adds IORING_REGISTER_PROBE, which fills in a structure with info
on what it supported or not. This will work even with sparse opcode
fields, which may happen in the future or even today if someone
backports specific features to older kernels.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-01-20 17:04:06 -07:00
Jens Axboe 10fef4bebf io_uring: account fixed file references correctly in batch
We can't assume that the whole batch has fixed files in it. If it's a
mix, or none at all, then we can end up doing a ref put that either
messes up accounting, or causes an oops if we have no fixed files at
all.

Also ensure we free requests properly between inflight accounted and
normal requests.

Fixes: 82c721577011 ("io_uring: extend batch freeing to cover more cases")
Reported-by: Dmitrii Dolgov <9erthalion6@gmail.com>
Reported-by: Pavel Begunkov <asml.silence@gmail.com>
Tested-by: Dmitrii Dolgov <9erthalion6@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-01-20 17:04:06 -07:00
Jens Axboe 354420f705 io_uring: add opcode to issue trace event
For some test apps at least, user_data is just zeroes. So it's not a
good way to tell what the command actually is. Add the opcode to the
issue trace point.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-01-20 17:04:06 -07:00