tree 5e51a188db23ab60450d530aca77cc0ee8b49008
parent 40dad765c045ab6dbd481cc4f00d04953e77510c
author Pavel Begunkov <asml.silence@gmail.com> 1623236845 +0100
committer Jens Axboe <axboe@kernel.dk> 1623680585 -0600

io_uring: fix blocking inline submission

There is a complaint against sys_io_uring_enter() blocking if it submits
stdin reads. The problem is in __io_file_supports_async(), which
sees that it's a cdev and allows it to be processed inline.

Punt char devices using generic rules of io_file_supports_async(),
including checking for presence of *_iter() versions of rw callbacks.
Apparently, it will affect most of cdevs with some exceptions like
null and zero devices.

Cc: stable@vger.kernel.org
Reported-by: Birk Hirdman <lonjil@gmail.com>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/d60270856b8a4560a639ef5f76e55eb563633599.1623236455.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>