Commit Graph

520 Commits

Author SHA1 Message Date
Pavel Begunkov
ac45abc0e2 io_uring: remove custom ->func handlers
In preparation of getting rid of work.func, this removes almost all
custom instances of it, leaving only io_wq_submit_work() and
io_link_work_cb(). And the last one will be dealt later.

Nothing fancy, just routinely remove *_finish() function and inline
what's left. E.g. remove io_fsync_finish() + inline __io_fsync() into
io_fsync().

As no users of io_req_cancelled() are left, delete it as well. The patch
adds extra switch lookup on cold-ish path, but that's overweighted by
nice diffstat and other benefits of the following patches.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-06-08 13:47:37 -06:00
Pavel Begunkov
3af73b286c io_uring: don't derive close state from ->func
Relying on having a specific work.func is dangerous, even if an opcode
handler set it itself. E.g. io_wq_assign_next() can modify it.

io_close() sets a custom work.func to indicate that
__close_fd_get_file() was already called. Fortunately, there is no bugs
with io_wq_assign_next() and close yet.

Still, do it safe and always be prepared to be called through
io_wq_submit_work(). Zero req->close.put_file in prep, and call
__close_fd_get_file() IFF it's NULL.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-06-08 13:47:37 -06:00
Denis Efremov
a8c73c1a61 io_uring: use kvfree() in io_sqe_buffer_register()
Use kvfree() to free the pages and vmas, since they are allocated by
kvmalloc_array() in a loop.

Fixes: d4ef647510 ("io_uring: avoid page allocation warnings")
Signed-off-by: Denis Efremov <efremov@linux.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20200605093203.40087-1-efremov@linux.com
2020-06-08 09:39:13 -06:00
Bijan Mottahedeh
efe68c1ca8 io_uring: validate the full range of provided buffers for access
Account for the number of provided buffers when validating the address
range.

Signed-off-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-06-08 09:39:13 -06:00
Jens Axboe
dddb3e26f6 io_uring: re-set iov base/len for buffer select retry
We already have the buffer selected, but we should set the iter list
again.

Cc: stable@vger.kernel.org # v5.7
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-06-04 11:45:29 -06:00
Pavel Begunkov
d2b6f48b69 io_uring: move send/recv IOPOLL check into prep
Fail recv/send in case of IORING_SETUP_IOPOLL earlier during prep,
so it'd be done only once. Removes duplication as well

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-06-04 11:14:19 -06:00
Pavel Begunkov
ec65fea5a8 io_uring: deduplicate io_openat{,2}_prep()
io_openat_prep() and io_openat2_prep() are identical except for how
struct open_how is built. Deduplicate it with a helper.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-06-04 11:14:19 -06:00
Pavel Begunkov
25e72d1012 io_uring: do build_open_how() only once
build_open_how() is just adjusting open_flags/mode. Do it once during
prep. It looks better than storing raw values for the future.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-06-04 11:14:19 -06:00
Pavel Begunkov
3232dd02af io_uring: fix {SQ,IO}POLL with unsupported opcodes
IORING_SETUP_IOPOLL is defined only for read/write, other opcodes should
be disallowed, otherwise it'll get an error as below. Also refuse
open/close with SQPOLL, as the polling thread wouldn't know which file
table to use.

RIP: 0010:io_iopoll_getevents+0x111/0x5a0
Call Trace:
 ? _raw_spin_unlock_irqrestore+0x24/0x40
 ? do_send_sig_info+0x64/0x90
 io_iopoll_reap_events.part.0+0x5e/0xa0
 io_ring_ctx_wait_and_kill+0x132/0x1c0
 io_uring_release+0x20/0x30
 __fput+0xcd/0x230
 ____fput+0xe/0x10
 task_work_run+0x67/0xa0
 do_exit+0x353/0xb10
 ? handle_mm_fault+0xd4/0x200
 ? syscall_trace_enter+0x18c/0x2c0
 do_group_exit+0x43/0xa0
 __x64_sys_exit_group+0x18/0x20
 do_syscall_64+0x60/0x1e0
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
[axboe: allow provide/remove buffers and files update]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-06-04 11:13:53 -06:00
Jens Axboe
fd2206e4e9 io_uring: disallow close of ring itself
A previous commit enabled this functionality, which also enabled O_PATH
to work correctly with io_uring. But we can't safely close the ring
itself, as the file handle isn't reference counted inside
io_uring_enter(). Instead of jumping through hoops to enable ring
closure, add a "soft" ->needs_file option, ->needs_file_no_error. This
enables O_PATH file descriptors to work, but still catches the case of
trying to close the ring itself.

Reported-by: Jann Horn <jannh@google.com>
Fixes: 904fbcb115 ("io_uring: remove 'fd is io_uring' from close path")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-06-02 17:22:24 -06:00
Linus Torvalds
1ee08de1e2 for-5.8/io_uring-2020-06-01
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Merge tag 'for-5.8/io_uring-2020-06-01' of git://git.kernel.dk/linux-block

Pull io_uring updates from Jens Axboe:
 "A relatively quiet round, mostly just fixes and code improvements. In
particular:

   - Make statx just use the generic statx handler, instead of open
     coding it. We don't need that anymore, as we always call it async
     safe (Bijan)

   - Enable closing of the ring itself. Also fixes O_PATH closure (me)

   - Properly name completion members (me)

   - Batch reap of dead file registrations (me)

   - Allow IORING_OP_POLL with double waitqueues (me)

   - Add tee(2) support (Pavel)

   - Remove double off read (Pavel)

   - Fix overflow cancellations (Pavel)

   - Improve CQ timeouts (Pavel)

   - Async defer drain fixes (Pavel)

   - Add support for enabling/disabling notifications on a registered
     eventfd (Stefano)

   - Remove dead state parameter (Xiaoguang)

   - Disable SQPOLL submit on dying ctx (Xiaoguang)

   - Various code cleanups"

* tag 'for-5.8/io_uring-2020-06-01' of git://git.kernel.dk/linux-block: (29 commits)
  io_uring: fix overflowed reqs cancellation
  io_uring: off timeouts based only on completions
  io_uring: move timeouts flushing to a helper
  statx: hide interfaces no longer used by io_uring
  io_uring: call statx directly
  statx: allow system call to be invoked from io_uring
  io_uring: add io_statx structure
  io_uring: get rid of manual punting in io_close
  io_uring: separate DRAIN flushing into a cold path
  io_uring: don't re-read sqe->off in timeout_prep()
  io_uring: simplify io_timeout locking
  io_uring: fix flush req->refs underflow
  io_uring: don't submit sqes when ctx->refs is dying
  io_uring: async task poll trigger cleanup
  io_uring: add tee(2) support
  splice: export do_tee()
  io_uring: don't repeat valid flag list
  io_uring: rename io_file_put()
  io_uring: remove req->needs_fixed_files
  io_uring: cleanup io_poll_remove_one() logic
  ...
2020-06-02 15:42:50 -07:00
Pavel Begunkov
7b53d59859 io_uring: fix overflowed reqs cancellation
Overflowed requests in io_uring_cancel_files() should be shed only of
inflight and overflowed refs. All other left references are owned by
someone else.

If refcount_sub_and_test() fails, it will go further and put put extra
ref, don't do that. Also, don't need to do io_wq_cancel_work()
for overflowed reqs, they will be let go shortly anyway.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-30 07:38:32 -06:00
Pavel Begunkov
bfe68a2219 io_uring: off timeouts based only on completions
Offset timeouts wait not for sqe->off non-timeout CQEs, but rather
sqe->off + number of prior inflight requests. Wait exactly for
sqe->off non-timeout completions

Reported-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-30 07:38:18 -06:00
Pavel Begunkov
360428f8c0 io_uring: move timeouts flushing to a helper
Separate flushing offset timeouts io_commit_cqring() by moving it into a
helper. Just a preparation, makes following patches clearer.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-30 07:38:17 -06:00
Bijan Mottahedeh
e62753e4e2 io_uring: call statx directly
Calling statx directly both simplifies the interface and avoids potential
incompatibilities between sync and async invokations.

Signed-off-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-26 16:48:06 -06:00
Bijan Mottahedeh
1d9e128803 io_uring: add io_statx structure
Separate statx data from open in io_kiocb. No functional changes.

Signed-off-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-26 16:48:06 -06:00
Pavel Begunkov
0bf0eefdab io_uring: get rid of manual punting in io_close
io_close() was punting async manually to skip grabbing files. Use
REQ_F_NO_FILE_TABLE instead, and pass it through the generic path
with -EAGAIN.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-26 13:31:09 -06:00
Pavel Begunkov
0451894522 io_uring: separate DRAIN flushing into a cold path
io_commit_cqring() assembly doesn't look good with extra code handling
drained requests. IOSQE_IO_DRAIN is slow and discouraged to be used in
a hot path, so try to minimise its impact by putting it into a helper
and doing a fast check.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-26 13:31:09 -06:00
Pavel Begunkov
56080b02ed io_uring: don't re-read sqe->off in timeout_prep()
SQEs are user writable, don't read sqe->off twice in io_timeout_prep()

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-26 13:31:08 -06:00
Pavel Begunkov
733f5c95e6 io_uring: simplify io_timeout locking
Move spin_lock_irq() earlier to have only 1 call site of it in
io_timeout(). It makes the flow easier.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-26 13:31:08 -06:00
Pavel Begunkov
4518a3cc27 io_uring: fix flush req->refs underflow
In io_uring_cancel_files(), after refcount_sub_and_test() leaves 0
req->refs, it calls io_put_req(), which would also put a ref. Call
io_free_req() instead.

Cc: stable@vger.kernel.org
Fixes: 2ca10259b4 ("io_uring: prune request from overflow list on flush")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-26 13:31:08 -06:00
Xiaoguang Wang
6b668c9b7f io_uring: don't submit sqes when ctx->refs is dying
When IORING_SETUP_SQPOLL is enabled, io_ring_ctx_wait_and_kill() will wait
for sq thread to idle by busy loop:

    while (ctx->sqo_thread && !wq_has_sleeper(&ctx->sqo_wait))
        cond_resched();

Above loop isn't very CPU friendly, it may introduce a short cpu burst on
the current cpu.

If ctx->refs is dying, we forbid sq_thread from submitting any further
SQEs. Instead they just get discarded when we exit.

Signed-off-by: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-20 08:41:26 -06:00
Xiaoguang Wang
d4ae271dfa io_uring: reset -EBUSY error when io sq thread is waken up
In io_sq_thread(), currently if we get an -EBUSY error and go to sleep,
we will won't clear it again, which will result in io_sq_thread() will
never have a chance to submit sqes again. Below test program test.c
can reveal this bug:

int main(int argc, char *argv[])
{
        struct io_uring ring;
        int i, fd, ret;
        struct io_uring_sqe *sqe;
        struct io_uring_cqe *cqe;
        struct iovec *iovecs;
        void *buf;
        struct io_uring_params p;

        if (argc < 2) {
                printf("%s: file\n", argv[0]);
                return 1;
        }

        memset(&p, 0, sizeof(p));
        p.flags = IORING_SETUP_SQPOLL;
        ret = io_uring_queue_init_params(4, &ring, &p);
        if (ret < 0) {
                fprintf(stderr, "queue_init: %s\n", strerror(-ret));
                return 1;
        }

        fd = open(argv[1], O_RDONLY | O_DIRECT);
        if (fd < 0) {
                perror("open");
                return 1;
        }

        iovecs = calloc(10, sizeof(struct iovec));
        for (i = 0; i < 10; i++) {
                if (posix_memalign(&buf, 4096, 4096))
                        return 1;
                iovecs[i].iov_base = buf;
                iovecs[i].iov_len = 4096;
        }

        ret = io_uring_register_files(&ring, &fd, 1);
        if (ret < 0) {
                fprintf(stderr, "%s: register %d\n", __FUNCTION__, ret);
                return ret;
        }

        for (i = 0; i < 10; i++) {
                sqe = io_uring_get_sqe(&ring);
                if (!sqe)
                        break;

                io_uring_prep_readv(sqe, 0, &iovecs[i], 1, 0);
                sqe->flags |= IOSQE_FIXED_FILE;

                ret = io_uring_submit(&ring);
                sleep(1);
                printf("submit %d\n", i);
        }

        for (i = 0; i < 10; i++) {
                io_uring_wait_cqe(&ring, &cqe);
                printf("receive: %d\n", i);
                if (cqe->res != 4096) {
                        fprintf(stderr, "ret=%d, wanted 4096\n", cqe->res);
                        ret = 1;
                }
                io_uring_cqe_seen(&ring, cqe);
        }

        close(fd);
        io_uring_queue_exit(&ring);
        return 0;
}
sudo ./test testfile
above command will hang on the tenth request, to fix this bug, when io
sq_thread is waken up, we reset the variable 'ret' to be zero.

Suggested-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-20 07:26:47 -06:00
Jens Axboe
b532576ed3 io_uring: don't add non-IO requests to iopoll pending list
We normally disable any commands that aren't specifically poll commands
for a ring that is setup for polling, but we do allow buffer provide and
remove commands to support buffer selection for polled IO. Once a
request is issued, we add it to the poll list to poll for completion. But
we should not do that for non-IO commands, as those request complete
inline immediately and aren't pollable. If we do, we can leave requests
on the iopoll list after they are freed.

Fixes: ddf0322db7 ("io_uring: add IORING_OP_PROVIDE_BUFFERS")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-19 21:20:27 -06:00
Bijan Mottahedeh
4f4eeba87c io_uring: don't use kiocb.private to store buf_index
kiocb.private is used in iomap_dio_rw() so store buf_index separately.

Signed-off-by: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>

Move 'buf_index' to a hole in io_kiocb.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-19 16:19:49 -06:00
Jens Axboe
e3aabf9554 io_uring: cancel work if task_work_add() fails
We currently move it to the io_wqe_manager for execution, but we cannot
safely do so as we may lack some of the state to execute it out of
context. As we cancel work anyway when the ring/task exits, just mark
this request as canceled and io_async_task_func() will do the right
thing.

Fixes: aa96bf8a9e ("io_uring: use io-wq manager as backup task if task is exiting")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-18 11:14:22 -06:00
Jens Axboe
310672552f io_uring: async task poll trigger cleanup
If the request is still hashed in io_async_task_func(), then it cannot
have been canceled and it's pointless to check. So save that check.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-17 17:43:31 -06:00
Jens Axboe
948a774945 io_uring: remove dead check in io_splice()
We checked for 'force_nonblock' higher up, so it's definitely false
at this point. Kill the check, it's a remnant of when we tried to do
inline splice without always punting to async context.

Fixes: 2fb3e82284 ("io_uring: punt splice async because of inode mutex")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-17 14:21:38 -06:00
Pavel Begunkov
f2a8d5c7a2 io_uring: add tee(2) support
Add IORING_OP_TEE implementing tee(2) support. Almost identical to
splice bits, but without offsets.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-17 14:10:07 -06:00
Pavel Begunkov
c11368a57b io_uring: don't repeat valid flag list
req->flags stores all sqe->flags. After checking that sqe->flags are
valid set if IOSQE* flags, no need to double check it, just forward them
all.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-17 14:10:07 -06:00
Pavel Begunkov
9f13c35b33 io_uring: rename io_file_put()
io_file_put() deals with flushing state's file refs, adding "state" to
its name makes it a bit clearer. Also, avoid double check of
state->file in __io_file_get() in some cases.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-17 14:10:07 -06:00
Pavel Begunkov
0cdaf760f4 io_uring: remove req->needs_fixed_files
A submission is "async" IIF it's done by SQPOLL thread. Instead of
passing @async flag into io_submit_sqes(), deduce it from ctx->flags.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-17 14:10:07 -06:00
Jens Axboe
3bfa5bcb26 io_uring: cleanup io_poll_remove_one() logic
We only need apoll in the one section, do the juggling with the work
restoration there. This removes a special case further down as well.

No functional changes in this patch.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-17 14:10:01 -06:00
Pavel Begunkov
bd2ab18a1d io_uring: fix FORCE_ASYNC req preparation
As for other not inlined requests, alloc req->io for FORCE_ASYNC reqs,
so they can be prepared properly.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-17 09:22:09 -06:00
Pavel Begunkov
650b548129 io_uring: don't prepare DRAIN reqs twice
If req->io is not NULL, it's already prepared. Don't do it again,
it's dangerous.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-17 09:22:09 -06:00
Jens Axboe
583863ed91 io_uring: initialize ctx->sqo_wait earlier
Ensure that ctx->sqo_wait is initialized as soon as the ctx is allocated,
instead of deferring it to the offload setup. This fixes a syzbot
reported lockdep complaint, which is really due to trying to wake_up
on an uninitialized wait queue:

RSP: 002b:00007fffb1fb9aa8 EFLAGS: 00000246 ORIG_RAX: 00000000000001a9
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441319
RDX: 0000000000000001 RSI: 0000000020000140 RDI: 000000000000047b
RBP: 0000000000010475 R08: 0000000000000001 R09: 00000000004002c8
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000402260
R13: 00000000004022f0 R14: 0000000000000000 R15: 0000000000000000
INFO: trying to register non-static key.
the code is fine but needs lockdep annotation.
turning off the locking correctness validator.
CPU: 1 PID: 7090 Comm: syz-executor222 Not tainted 5.7.0-rc1-next-20200415-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x188/0x20d lib/dump_stack.c:118
 assign_lock_key kernel/locking/lockdep.c:913 [inline]
 register_lock_class+0x1664/0x1760 kernel/locking/lockdep.c:1225
 __lock_acquire+0x104/0x4c50 kernel/locking/lockdep.c:4234
 lock_acquire+0x1f2/0x8f0 kernel/locking/lockdep.c:4934
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0x8c/0xbf kernel/locking/spinlock.c:159
 __wake_up_common_lock+0xb4/0x130 kernel/sched/wait.c:122
 io_cqring_ev_posted+0xa5/0x1e0 fs/io_uring.c:1160
 io_poll_remove_all fs/io_uring.c:4357 [inline]
 io_ring_ctx_wait_and_kill+0x2bc/0x5a0 fs/io_uring.c:7305
 io_uring_create fs/io_uring.c:7843 [inline]
 io_uring_setup+0x115e/0x22b0 fs/io_uring.c:7870
 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x49/0xb3
RIP: 0033:0x441319
Code: e8 5c ae 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 bb 0a fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fffb1fb9aa8 EFLAGS: 00000246 ORIG_RAX: 00000000000001a9

Reported-by: syzbot+8c91f5d054e998721c57@syzkaller.appspotmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-17 09:20:00 -06:00
Jens Axboe
6a4d07cde5 io_uring: file registration list and lock optimization
There's no point in using list_del_init() on entries that are going
away, and the associated lock is always used in process context so
let's not use the IRQ disabling+saving variant of the spinlock.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-15 14:37:14 -06:00
Stefano Garzarella
7e55a19cf6 io_uring: add IORING_CQ_EVENTFD_DISABLED to the CQ ring flags
This new flag should be set/clear from the application to
disable/enable eventfd notifications when a request is completed
and queued to the CQ ring.

Before this patch, notifications were always sent if an eventfd is
registered, so IORING_CQ_EVENTFD_DISABLED is not set during the
initialization.

It will be up to the application to set the flag after initialization
if no notifications are required at the beginning.

Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-15 12:16:59 -06:00
Stefano Garzarella
0d9b5b3af1 io_uring: add 'cq_flags' field for the CQ ring
This patch adds the new 'cq_flags' field that should be written by
the application and read by the kernel.

This new field is available to the userspace application through
'cq_off.flags'.
We are using 4-bytes previously reserved and set to zero. This means
that if the application finds this field to zero, then the new
functionality is not supported.

In the next patch we will introduce the first flag available.

Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-15 12:16:59 -06:00
Jens Axboe
18bceab101 io_uring: allow POLL_ADD with double poll_wait() users
Some file descriptors use separate waitqueues for their f_ops->poll()
handler, most commonly one for read and one for write. The io_uring
poll implementation doesn't work with that, as the 2nd poll_wait()
call will cause the io_uring poll request to -EINVAL.

This affects (at least) tty devices and /dev/random as well. This is a
big problem for event loops where some file descriptors work, and others
don't.

With this fix, io_uring handles multiple waitqueues.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-15 11:56:54 -06:00
Jens Axboe
4a38aed2a0 io_uring: batch reap of dead file registrations
We currently embed and queue a work item per fixed_file_ref_node that
we update, but if the workload does a lot of these, then the associated
kworker-events overhead can become quite noticeable.

Since we rarely need to wait on these, batch them at 1 second intervals
instead. If we do need to wait for them, we just flush the pending
delayed work.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-15 11:56:18 -06:00
Jens Axboe
0f158b4cf2 io_uring: name sq thread and ref completions
We used to have three completions, now we just have two. With the two,
let's not allocate them dynamically, just embed then in the ctx and
name them appropriately.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-14 17:18:39 -06:00
Jens Axboe
9d9e88a24c io_uring: polled fixed file must go through free iteration
When we changed the file registration handling, it became important to
iterate the bulk request freeing list for fixed files as well, or we
miss dropping the fixed file reference. If not, we're leaking references,
and we'll get a kworker stuck waiting for file references to disappear.

This also means we can remove the special casing of fixed vs non-fixed
files, we need to iterate for both and we can just rely on
__io_req_aux_free() doing io_put_file() instead of doing it manually.

Fixes: 0558955373 ("io_uring: refactor file register/unregister/update handling")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-13 13:00:00 -06:00
Xiaoming Ni
8469508951 io_uring: remove duplicate semicolon at the end of line
Remove duplicate semicolon at the end of line in io_file_from_index()

Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-11 09:04:05 -06:00
Pavel Begunkov
c96874265c io_uring: fix zero len do_splice()
do_splice() doesn't expect len to be 0. Just always return 0 in this
case as splice(2) does.

Fixes: 7d67af2c01 ("io_uring: add splice(2) support")
Reported-by: Jann Horn <jannh@google.com>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-09 10:16:10 -06:00
Xiaoguang Wang
7d01bd745a io_uring: remove obsolete 'state' parameter
The "struct io_submit_state *state" parameter is not used, remove it.

Signed-off-by: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-08 21:29:47 -06:00
Jens Axboe
904fbcb115 io_uring: remove 'fd is io_uring' from close path
The attempt protecting us from closing the ring itself wasn't really
complete, and we actually don't need it. The referencing of requests
themselve, and the references they hold on the ring, ensures that the
life time of the ring is sane. With the check removed, we can also
remove the need to have the close operation fget() the file.

Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-08 21:27:24 -06:00
Jens Axboe
63ff822358 io_uring: don't use 'fd' for openat/openat2/statx
We currently make some guesses as when to open this fd, but in reality
we have no business (or need) to do so at all. In fact, it makes certain
things fail, like O_PATH.

Remove the fd lookup from these opcodes, we're just passing the 'fd' to
generic helpers anyway. With that, we can also remove the special casing
of fd values in io_req_needs_file(), and the 'fd_non_neg' check that
we have. And we can ensure that we only read sqe->fd once.

This fixes O_PATH usage with openat/openat2, and ditto statx path side
oddities.

Cc: stable@vger.kernel.org: # v5.6
Reported-by: Max Kellermann <mk@cm4all.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-07 14:56:15 -06:00
Xiaoguang Wang
7f13657d14 io_uring: handle -EFAULT properly in io_uring_setup()
If copy_to_user() in io_uring_setup() failed, we'll leak many kernel
resources, which will be recycled until process terminates. This bug
can be reproduced by using mprotect to set params to PROT_READ. To fix
this issue, refactor io_uring_create() a bit to add a new 'struct
io_uring_params __user *params' parameter and move the copy_to_user()
in io_uring_setup() to io_uring_setup(), if copy_to_user() failed,
we can free kernel resource properly.

Suggested-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-05 13:18:11 -06:00
Xiaoguang Wang
d8f1b9716c io_uring: fix mismatched finish_wait() calls in io_uring_cancel_files()
The prepare_to_wait() and finish_wait() calls in io_uring_cancel_files()
are mismatched. Currently I don't see any issues related this bug, just
find it by learning codes.

Signed-off-by: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-04 09:07:14 -06:00