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  1. 22 6月, 2020 13 次提交
  3. 18 6月, 2020 5 次提交
    • X
      io_uring: fix possible race condition against REQ_F_NEED_CLEANUP · 6f2cc166
      由 Xiaoguang Wang 提交于 
      In io_read() or io_write(), when io request is submitted successfully,
it'll go through the below sequence:

    kfree(iovec);
    req->flags &= ~REQ_F_NEED_CLEANUP;
    return ret;

But clearing REQ_F_NEED_CLEANUP might be unsafe. The io request may
already have been completed, and then io_complete_rw_iopoll()
and io_complete_rw() will be called, both of which will also modify
req->flags if needed. This causes a race condition, with concurrent
non-atomic modification of req->flags.

To eliminate this race, in io_read() or io_write(), if io request is
submitted successfully, we don't remove REQ_F_NEED_CLEANUP flag. If
REQ_F_NEED_CLEANUP is set, we'll leave __io_req_aux_free() to the
iovec cleanup work correspondingly.

Cc: stable@vger.kernel.org
Signed-off-by: NXiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
      6f2cc166
    • J
      io_uring: reap poll completions while waiting for refs to drop on exit · 56952e91
      由 Jens Axboe 提交于 
      If we're doing polled IO and end up having requests being submitted
async, then completions can come in while we're waiting for refs to
drop. We need to reap these manually, as nobody else will be looking
for them.

Break the wait into 1/20th of a second time waits, and check for done
poll completions if we time out. Otherwise we can have done poll
completions sitting in ctx->poll_list, which needs us to reap them but
we're just waiting for them.

Cc: stable@vger.kernel.org
Signed-off-by: NJens Axboe <axboe@kernel.dk>
      56952e91
    • J
      io_uring: acquire 'mm' for task_work for SQPOLL · 9d8426a0
      由 Jens Axboe 提交于 
      If we're unlucky with timing, we could be running task_work after
having dropped the memory context in the sq thread. Since dropping
the context requires a runnable task state, we cannot reliably drop
it as part of our check-for-work loop in io_sq_thread(). Instead,
abstract out the mm acquire for the sq thread into a helper, and call
it from the async task work handler.

Cc: stable@vger.kernel.org # v5.7
Signed-off-by: NJens Axboe <axboe@kernel.dk>
      9d8426a0
    • X
      io_uring: add memory barrier to synchronize io_kiocb's result and iopoll_completed · bbde017a
      由 Xiaoguang Wang 提交于 
      In io_complete_rw_iopoll(), stores to io_kiocb's result and iopoll
completed are two independent store operations, to ensure that once
iopoll_completed is ture and then req->result must been perceived by
the cpu executing io_do_iopoll(), proper memory barrier should be used.

And in io_do_iopoll(), we check whether req->result is EAGAIN, if it is,
we'll need to issue this io request using io-wq again. In order to just
issue a single smp_rmb() on the completion side, move the re-submit work
to io_iopoll_complete().

Cc: stable@vger.kernel.org
Signed-off-by: NXiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
[axboe: don't set ->iopoll_completed for -EAGAIN retry]
Signed-off-by: NJens Axboe <axboe@kernel.dk>
      bbde017a
    • X
      io_uring: don't fail links for EAGAIN error in IOPOLL mode · 2d7d6792
      由 Xiaoguang Wang 提交于 
      In IOPOLL mode, for EAGAIN error, we'll try to submit io request
again using io-wq, so don't fail rest of links if this io request
has links.

Cc: stable@vger.kernel.org
Signed-off-by: NXiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
      2d7d6792
  5. 15 6月, 2020 6 次提交
  7. 11 6月, 2020 7 次提交
  9. 10 6月, 2020 2 次提交
  11. 09 6月, 2020 4 次提交
  13. 08 6月, 2020 2 次提交
  15. 05 6月, 2020 1 次提交